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Scott EM, Magaret A, Kuypers J, Tielsch JM, Katz J, Khatry SK, Stewart L, Shrestha L, LeClerq SC, Englund JA, Chu HY. Risk factors and patterns of household clusters of respiratory viruses in rural Nepal. Epidemiol Infect 2019; 147:e288. [PMID: 31607271 PMCID: PMC6805793 DOI: 10.1017/s0950268819001754] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 09/12/2019] [Accepted: 09/18/2019] [Indexed: 11/18/2022] Open
Abstract
Viral pneumonia is an important cause of death and morbidity among infants worldwide. Transmission of non-influenza respiratory viruses in households can inform preventative interventions and has not been well-characterised in South Asia. From April 2011 to April 2012, household members of pregnant women enrolled in a randomised trial of influenza vaccine in rural Nepal were surveyed weekly for respiratory illness until 180 days after birth. Nasal swabs were tested by polymerase chain reaction for respiratory viruses in symptomatic individuals. A transmission event was defined as a secondary case of the same virus within 14 days of initial infection within a household. From 555 households, 825 initial viral illness episodes occurred, resulting in 79 transmission events. The overall incidence of transmission was 1.14 events per 100 person-weeks. Risk of transmission incidence was associated with an index case age 1-4 years (incidence rate ratio (IRR) 2.35; 95% confidence interval (CI) 1.40-3.96), coinfection as initial infection (IRR 1.94; 95% CI 1.05-3.61) and no electricity in household (IRR 2.70; 95% CI 1.41-5.00). Preventive interventions targeting preschool-age children in households in resource-limited settings may decrease the risk of transmission to vulnerable household members, such as young infants.
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Affiliation(s)
- E. M. Scott
- School of Medicine, University of Washington, Seattle, WA, USA
| | - A. Magaret
- School of Medicine, University of Washington, Seattle, WA, USA
| | - J. Kuypers
- School of Medicine, University of Washington, Seattle, WA, USA
| | - J. M. Tielsch
- Department of Global Health, Milken Institute School of Public Health, George Washington University, Washington, DC, USA
| | - J. Katz
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - S. K. Khatry
- Nepal Nutrition Intervention Project – Sarlahi, Kathmandu, Nepal
| | - L. Stewart
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - L. Shrestha
- Department of Paediatrics and Child Health, Institute of Medicine, Tribhuvan University, Kathmandu, Nepal
| | - S. C. LeClerq
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
- Nepal Nutrition Intervention Project – Sarlahi, Kathmandu, Nepal
| | - J. A. Englund
- Seattle Children's Hospital and Research Institute, University of Washington, Seattle, WA, USA
| | - H. Y. Chu
- School of Medicine, University of Washington, Seattle, WA, USA
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52
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Pebody R, Moyes J, Hirve S, Campbell H, Jackson S, Moen A, Nair H, Simões EAF, Smith PG, Wairagkar N, Zhang W. Approaches to use the WHO respiratory syncytial virus surveillance platform to estimate disease burden. Influenza Other Respir Viruses 2019; 14:615-621. [PMID: 31595655 PMCID: PMC7578280 DOI: 10.1111/irv.12667] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 06/11/2019] [Accepted: 06/14/2019] [Indexed: 12/01/2022] Open
Abstract
The World Health Organization (WHO) recently completed the first phase of a RSV surveillance pilot study in fourteen countries (two to three in each WHO region) building on the Global Influenza Surveillance and Response System (GISRS). This active surveillance strategy had several objectives including understanding RSV-related health burden in a variety of settings. A range of approaches can be used to estimate disease burden; most approaches could not be applied by participating countries in the WHO surveillance pilot. This article provides the recommendations made by WHO for strengthening and expanding the scope of the RSV surveillance in the next phase to enable burden estimation.
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Affiliation(s)
| | - Jocelyn Moyes
- Center for Respiratory Diseases and Meningitis, National Institute for Communicable Diseases, Johannesburg, South Africa
| | | | - Harry Campbell
- Usher Institute of Population Health Research and Informatics, University of Edinburgh, Edinburgh, UK
| | - Sandra Jackson
- Global Influenza Program, World Health Organization, Geneva, Switzerland
| | - Ann Moen
- Global Influenza Program, World Health Organization, Geneva, Switzerland
| | - Harish Nair
- Usher Institute of Population Health Research and Informatics, University of Edinburgh, Edinburgh, UK
| | - Eric A F Simões
- Center for Global Health, Colorado School of Public Health, Aurora, CO, USA
| | - Peter G Smith
- MRC Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
| | | | - Wenqing Zhang
- Global Influenza Program, World Health Organization, Geneva, Switzerland
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53
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Immunological Lessons from Respiratory Syncytial Virus Vaccine Development. Immunity 2019; 51:429-442. [DOI: 10.1016/j.immuni.2019.08.007] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/30/2019] [Accepted: 08/07/2019] [Indexed: 12/30/2022]
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54
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Kiti MC, Melegaro A, Cattuto C, Nokes DJ. Study design and protocol for investigating social network patterns in rural and urban schools and households in a coastal setting in Kenya using wearable proximity sensors. Wellcome Open Res 2019; 4:84. [PMID: 31489381 PMCID: PMC6719676 DOI: 10.12688/wellcomeopenres.15268.2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2019] [Indexed: 11/28/2022] Open
Abstract
Background: Social contact patterns shape the transmission of respiratory infections spread via close interactions. There is a paucity of observational data from schools and households, particularly in developing countries. Portable wireless sensors can record unbiased proximity events between individuals facing each other, shedding light on pathways of infection transmission. Design and methods: The aim is to characterize face-to-face contact patterns that may shape the transmission of respiratory infections in schools and households in Kilifi, Kenya. Two schools, one each from a rural and urban area, will be purposively selected. From each school, 350 students will be randomly selected proportional to class size and gender to participate. Nine index students from each school will be randomly selected and followed-up to their households. All index household residents will be recruited into the study. A further 3-5 neighbouring households will also be recruited to give a maximum of 350 participants per household setting. The sample size per site is limited by the number of sensors available for data collection. Each participant will wear a wireless proximity sensor lying on their chest area for 7 consecutive days. Data on proximal dyadic interactions will be collected automatically by the sensors only for participants who are face-to-face. Key characteristics of interest include the distribution of degree and the frequency and duration of contacts and their variation in rural and urban areas. These will be stratified by age, gender, role, and day of the week. Expected results: Resultant data will inform on social contact patterns in rural and urban areas of a previously unstudied population. Ensuing data will be used to parameterize mathematical simulation models of transmission of a range of respiratory viruses, including respiratory syncytial virus, and used to explore the impact of intervention measures such as vaccination and social distancing.
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Affiliation(s)
- Moses Chapa Kiti
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
| | - Alessia Melegaro
- Department of Social and Political Sciences, Bocconi University, Milan, Italy
| | - Ciro Cattuto
- Data Science Laboratory, Institute for Scientific Interchange Foundation, Turin, Italy
| | - David James Nokes
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya.,Zeeman Institute of Systems Biology and Infectious Disease Research, University of Warwick, Coventry, UK.,School of Life Sciences, University of Warwick, Coventry, UK
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55
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Genomic analysis of respiratory syncytial virus infections in households and utility in inferring who infects the infant. Sci Rep 2019; 9:10076. [PMID: 31296922 PMCID: PMC6624209 DOI: 10.1038/s41598-019-46509-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 06/26/2019] [Indexed: 12/18/2022] Open
Abstract
Infants (under 1-year-old) are at most risk of life threatening respiratory syncytial virus (RSV) disease. RSV epidemiological data alone has been insufficient in defining who acquires infection from whom (WAIFW) within households. We investigated RSV genomic variation within and between infected individuals and assessed its potential utility in tracking transmission in households. Over an entire single RSV season in coastal Kenya, nasal swabs were collected from members of 20 households every 3-4 days regardless of symptom status and screened for RSV nucleic acid. Next generation sequencing was used to generate >90% RSV full-length genomes for 51.1% of positive samples (191/374). Single nucleotide polymorphisms (SNPs) observed during household infection outbreaks ranged from 0-21 (median: 3) while SNPs observed during single-host infection episodes ranged from 0-17 (median: 1). Using the viral genomic data alone there was insufficient resolution to fully reconstruct within-household transmission chains. For households with clear index cases, the most likely source of infant infection was via a toddler (aged 1 to <3 years-old) or school-aged (aged 6 to <12 years-old) co-occupant. However, for best resolution of WAIFW within households, we suggest an integrated analysis of RSV genomic and epidemiological data.
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56
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Mahikul W, J. White L, Poovorawan K, Soonthornworasiri N, Sukontamarn P, Chanthavilay P, F. Medley G, Pan-ngum W. Modeling household dynamics on Respiratory Syncytial Virus (RSV). PLoS One 2019; 14:e0219323. [PMID: 31287832 PMCID: PMC6615606 DOI: 10.1371/journal.pone.0219323] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Accepted: 06/20/2019] [Indexed: 11/19/2022] Open
Abstract
Respiratory Syncytial Virus (RSV) is the most common cause of respiratory tract infection in infants and children and shows increasing trend among elderly people worldwide. In many developing country settings, population and household structures have gone through some significant changes in the past decades, namely fewer births, more elderly population, and smaller household size but more RSV high-risk individuals. These dynamics have been captured in a mathematical model with RSV transmission dynamics to predict the disease burden on the detailed population for future targeted interventions. The population and disease dynamics model was constructed and tested against the hospitalization data for Acute Lower Respiratory Tract Infection due to RSV in rural Thai settings between 2005 and 2011. The proportion of extended families is predicted to increase by about 10% from 2005 to 2020, especially for those with elderly population, while the classic nuclear family type (with adults and children) will decline by about 10%. For RSV, infections from extended family type (approximately 60% of all household types) have majorly contributed to the force of infection (FOI). While the model predicted the increase of FOI from the extended family by 15% from 2005 to 2020, the FOI contributed by other household types would be either stable or decrease in the same time period. RSV incidence rate is predominantly high among babies (92.2%) and has been predicted to decrease slightly over time (from 940 to 864 cases per 100,000 population by 2020), while the incidence rates among children and elderly people may remain steadily low over the same period. However, the estimated incidence rates among elderly people were twice than those in children. The model predicts that approximately 60% of FOI for RSV will come from members of the extended family type. The incidence rate of RSV among children and elderly in extended families was about 20 times lower than that in infants and the trend is steady. Targeted intervention strategies, such as health education in some specific groups and targeted vaccination, may be considered, with the focus on extended family type. Target interventions on babies can lessen the transmission to children and elderly especially when transmission within households of extended family type is high.
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Affiliation(s)
- Wiriya Mahikul
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Lisa J. White
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Kittiyod Poovorawan
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | | | - Phetsavanh Chanthavilay
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Institute of Research and Education Development, UHS, Vientiane, Lao PDR
| | - Graham F. Medley
- Centre for Mathematical Modelling of Infectious Disease & Department of Global Health and Development, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Wirichada Pan-ngum
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
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57
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Abstract
Respiratory syncytial virus remains a major cause of infantile respiratory illness globally. Infants in the developing world experience the highest burden of mortality and morbidity. Risk factors associated with respiratory syncytial virus infection and progression to severe disease include household crowding, preterm birth and low birth weight. Maternally-derived antibody has a role in protection of infants through transplacental antibody transfer and breast milk antibody. Promising prevention strategies that are under development include vaccination during pregnancy and monoclonal antibody administration at birth.
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58
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Kombe IK, Munywoki PK, Baguelin M, Nokes DJ, Medley GF. Model-based estimates of transmission of respiratory syncytial virus within households. Epidemics 2019; 27:1-11. [PMID: 30591267 PMCID: PMC6543068 DOI: 10.1016/j.epidem.2018.12.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 12/14/2018] [Accepted: 12/14/2018] [Indexed: 12/16/2022] Open
Abstract
INTRODUCTION Respiratory syncytial virus (RSV) causes a significant respiratory disease burden in the under 5 population. The transmission pathway to young children is not fully quantified in low-income settings, and this information is required to design interventions. METHODS We used an individual level transmission model to infer transmission parameters using data collected from 493 individuals distributed across 47 households over a period of 6 months spanning the 2009/2010 RSV season. A total of 208 episodes of RSV were observed from 179 individuals. We model competing transmission risk from within household exposure and community exposure while making a distinction between RSV groups A and B. RESULTS We find that 32-53% of all RSV transmissions are between members of the same household; the rate of pair-wise transmission is 58% (95% CrI: 30-74%) lower in larger households (≥8 occupants) than smaller households; symptomatic individuals are 2-7 times more infectious than asymptomatic individuals i.e. 2.48 (95% CrI: 1.22-5.57) among symptomatic individuals with low viral load and 6.7(95% CrI: 2.56-16) among symptomatic individuals with high viral load; previous infection reduces susceptibility to re-infection within the same epidemic by 47% (95% CrI: 17%-68%) for homologous RSV group and 39% (95%CrI: -8%-69%) for heterologous group; RSV B is more frequently introduced into the household, and RSV A is more rapidly transmitted once in the household. DISCUSSION Our analysis presents the first transmission modelling of cohort data for RSV and we find that it is important to consider the household social structuring and household size when modelling transmission. The increased infectiousness of symptomatic individuals implies that a vaccine against RSV related disease would also have an impact on infection transmission. Together, the weak cross immunity between RSV groups and the possibility of different transmission niches could form part of the explanation for the group co-existence.
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Affiliation(s)
- Ivy K Kombe
- KEMRI-Wellcome Trust Research Programme, KEMRI Center for Geographical Medical Research-Coast, P.O. Box 230-80108, Kilifi, Kenya; Centre for Mathematical Modelling of Infectious Disease and Department of Global Health and Development, London School of Hygiene and Tropical Medicine, London, WC1H 9SH, UK.
| | - Patrick K Munywoki
- KEMRI-Wellcome Trust Research Programme, KEMRI Center for Geographical Medical Research-Coast, P.O. Box 230-80108, Kilifi, Kenya
| | - Marc Baguelin
- Centre for Mathematical Modelling of Infectious Disease and Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, WC1H 9SH, UK
| | - D James Nokes
- KEMRI-Wellcome Trust Research Programme, KEMRI Center for Geographical Medical Research-Coast, P.O. Box 230-80108, Kilifi, Kenya; School of Life Sciences and Zeeman Institute for Systems Biology & Infectious Disease Epidemiology Research, University of Warwick, Coventry, CV4 7AL, UK
| | - Graham F Medley
- Centre for Mathematical Modelling of Infectious Disease and Department of Global Health and Development, London School of Hygiene and Tropical Medicine, London, WC1H 9SH, UK
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59
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Kiti MC, Melegaro A, Cattuto C, Nokes DJ. Study design and protocol for investigating social network patterns in rural and urban schools and households in a coastal setting in Kenya using wearable proximity sensors. Wellcome Open Res 2019; 4:84. [DOI: 10.12688/wellcomeopenres.15268.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/16/2019] [Indexed: 11/20/2022] Open
Abstract
Background: Social contact patterns shape the transmission of respiratory infections spread via close interactions. There is a paucity of observational data from schools and households, particularly in developing countries. Portable wireless sensors can record unbiased proximity events between individuals facing each other, shedding light on pathways of infection transmission. Design and methods: The aim is to characterize face-to-face contact patterns that may shape the transmission of respiratory infections in schools and households in Kilifi, Kenya. Two schools, one each from a rural and urban area, will be purposively selected. From each school, 350 students will be randomly selected proportional to class size and gender to participate. Nine index students from each school will be randomly selected and followed-up to their households. All index household residents will be recruited into the study. A further 3-5 neighbouring households will also be recruited to give a maximum of 350 participants per household setting. The sample size per site is limited by the number of sensors available for data collection. Each participant will wear a wireless proximity sensor lying on their chest area for 7 consecutive days. Data on proximal dyadic interactions will be collected automatically by the sensors only for participants who are face-to-face. Key characteristics of interest include the distribution of degree and the frequency and duration of contacts and their variation in rural and urban areas. These will be stratified by age, gender, role, and day of the week. Expected results: Resultant data will inform on social contact patterns in rural and urban areas of a previously unstudied population. Ensuing data will be used to parameterize mathematical simulation models of transmission of a range of respiratory viruses, including respiratory syncytial virus, and used to explore the impact of intervention measures such as vaccination and social distancing.
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60
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Aranda SS, Polack FP. Prevention of Pediatric Respiratory Syncytial Virus Lower Respiratory Tract Illness: Perspectives for the Next Decade. Front Immunol 2019; 10:1006. [PMID: 31134078 PMCID: PMC6524688 DOI: 10.3389/fimmu.2019.01006] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 04/18/2019] [Indexed: 12/30/2022] Open
Abstract
The landscape of infant bronchiolitis and viral pneumonia may be altered by preventive interventions against respiratory syncytial virus under evaluation today. Pediatric wards in 2018 in developing countries may differ from those attended by future generation pediatricians who may not witness the packed emergency rooms, lack of available beds, or emergency situations that all physicians caring for children with RSV experience every year. In this review, we describe and discuss different prevention strategies under evaluation to protect pediatric patients. Then, we outline a number of potential challenges, benefits, and concerns that may result from successful interventions after licensure.
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61
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Sarna M, Ware RS, Lambert SB, Sloots TP, Nissen MD, Grimwood K. Timing of First Respiratory Virus Detections in Infants: A Community-Based Birth Cohort Study. J Infect Dis 2019; 217:418-427. [PMID: 29165576 PMCID: PMC7107408 DOI: 10.1093/infdis/jix599] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 11/16/2017] [Indexed: 11/13/2022] Open
Abstract
Background Determining timing of first virus detection episodes (fVDEs) for different respiratory viruses in infants identifies risk periods and informs preventive interventions, including vaccination. We describe the ages and nature of fVDEs in an infant birth cohort and explore factors associated with increased odds of symptomatic fVDEs. Methods The Observational Research in Childhood Infectious Diseases (ORChID) study is a community-based birth cohort describing acute respiratory infections in infants until their second birthday. Parents recorded daily symptoms and collected nose swabs weekly, which were batch-tested using polymerase chain reaction assays for 17 respiratory viruses. Results One hundred fifty-eight infants participated in ORChID. The median age for fVDEs was 2.9 months for human rhinovirus (HRV) but was ≥13.9 months for other respiratory viruses. Overall, 52% of HRV fVDEs were symptomatic, compared with 57%–83% of other fVDEs. Respiratory syncytial virus and human metapneumovirus fVDEs were more severe than HRV fVDEs. Older age and the winter season were associated with symptomatic episodes. Conclusions Infants do not always experience respiratory symptoms with their fVDE. Predominance of early HRV detections highlights the need for timing any intervention early in life. fVDEs from other respiratory viruses most commonly occur when maternal vaccines may no longer provide protection.
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Affiliation(s)
- Mohinder Sarna
- School of Public Health, University of Queensland, Brisbane.,UQ Child Health Research Centre, School of Medicine, University of Queensland, Brisbane
| | - Robert S Ware
- UQ Child Health Research Centre, School of Medicine, University of Queensland, Brisbane.,Menzies Health Institute Queensland, Griffith University, Gold Coast
| | - Stephen B Lambert
- UQ Child Health Research Centre, School of Medicine, University of Queensland, Brisbane
| | - Theo P Sloots
- UQ Child Health Research Centre, School of Medicine, University of Queensland, Brisbane
| | - Michael D Nissen
- UQ Child Health Research Centre, School of Medicine, University of Queensland, Brisbane
| | - Keith Grimwood
- School of Medicine and Menzies Health Institute Queensland, Griffith University, Gold Coast.,Departments of Infectious Diseases and Paediatrics, Gold Coast Health, Queensland, Australia
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62
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Kamau E, Onyango CO, Otieno GP, Kiyuka PK, Agoti CN, Medley GF, Cane PA, Nokes DJ, Munywoki PK. An Intensive, Active Surveillance Reveals Continuous Invasion and High Diversity of Rhinovirus in Households. J Infect Dis 2019; 219:1049-1057. [PMID: 30576538 PMCID: PMC6420174 DOI: 10.1093/infdis/jiy621] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 11/21/2018] [Indexed: 11/14/2022] Open
Abstract
We report on infection patterns in 5 households (78 participants) delineating the natural history of human rhinovirus (HRV). Nasopharyngeal collections were obtained every 3-4 days irrespective of symptoms, over a 6-month period, with molecular screening for HRV and typing by sequencing VP4/VP2 junction. Overall, 311/3468 (8.9%) collections were HRV positive: 256 were classified into 3 species: 104 (40.6%) HRV-A; 14 (5.5%) HRV-B, and 138 (53.9%) HRV-C. Twenty-six known HRV types (13 HRV-A, 3 HRV-B, and 10 HRV-C) were identified (A75, C1, and C35 being most frequent). We observed continuous invasion and temporal clustering of HRV types in households (range 5-13 over 6 months). Intrahousehold transmission was independent of clinical status but influenced by age. Most (89.0%) of HRV infection episodes were limited to <14 days. Individual repeat infections were frequent (range 1-7 over 6 months), decreasing with age, and almost invariably heterotypic, indicative of lasting type-specific immunity and low cross-type protection.
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Affiliation(s)
- Everlyn Kamau
- Epidemiology and Demography Department, Kenya Medical Research Institute – Wellcome Trust Research Programme, Kilifi
| | - Clayton O Onyango
- Epidemiology and Demography Department, Kenya Medical Research Institute – Wellcome Trust Research Programme, Kilifi
- Centers for Disease Control and Prevention, Nairobi
| | - Grieven P Otieno
- Epidemiology and Demography Department, Kenya Medical Research Institute – Wellcome Trust Research Programme, Kilifi
| | - Patience K Kiyuka
- Epidemiology and Demography Department, Kenya Medical Research Institute – Wellcome Trust Research Programme, Kilifi
| | - Charles N Agoti
- Epidemiology and Demography Department, Kenya Medical Research Institute – Wellcome Trust Research Programme, Kilifi
- School of Health and Human Sciences, Pwani University, Kilifi, Kenya
| | - Graham F Medley
- Centre for Mathematical Modelling of Infectious Disease and Department of Global Health and Development, London School of Hygiene and Tropical Medicine, Salisbury
| | | | - D James Nokes
- Epidemiology and Demography Department, Kenya Medical Research Institute – Wellcome Trust Research Programme, Kilifi
- School of Life Sciences and Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, University of Warwick, Coventry, United Kingdom
| | - Patrick K Munywoki
- Epidemiology and Demography Department, Kenya Medical Research Institute – Wellcome Trust Research Programme, Kilifi
- School of Health and Human Sciences, Pwani University, Kilifi, Kenya
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63
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Otomaru H, Kamigaki T, Tamaki R, Okamoto M, Alday PP, Tan AG, Manalo JI, Segubre-Mercado E, Inobaya MT, Tallo V, Lupisan S, Oshitani H. Transmission of Respiratory Syncytial Virus Among Children Under 5 Years in Households of Rural Communities, the Philippines. Open Forum Infect Dis 2019; 6:ofz045. [PMID: 30882012 PMCID: PMC6411217 DOI: 10.1093/ofid/ofz045] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 12/21/2018] [Accepted: 02/01/2019] [Indexed: 01/03/2023] Open
Abstract
Background To develop a more effective vaccination strategy for reducing the impact of respiratory syncytial virus (RSV) infection, especially in young infants (<6 months old), it is necessary to understand the transmission dynamics of RSV. Methods We conducted a community-based prospective cohort study from 2014 to 2016 in Biliran Province, the Philippines, on children <5 years old. We collected nasopharyngeal swabs from symptomatic children with acute respiratory infection (ARI) during household visits and at health facilities. In households (n = 181) with RSV-positive ARI cases (RSV-ARI), we also identified ARI episodes among other children <5 years old in the same household. In addition, we determined the serial interval to estimate the basic reproduction number (R0), the average number of secondary cases generated by a single primary case. Results In the 181 households analyzed, we found 212 RSV-ARI in 152 households with a single case and 29 households with multiple cases, which included 29 1st RSV-ARI and 31 2nd RSV-ARI. We also found possible index cases among children <5 years old in the same household for 29.0% (18 of 62) of young infants with RSV-ARI. The estimated mean serial interval was 3.2 days, and R0 was estimated to be 0.92–1.33 for RSV-A and 1.04–1.76 for RSV-B, which varied between different times (2014 and 2015) and places. Conclusions Young infants are likely to acquire RSV infection from older children in the same household. Therefore, vaccination targeting older children might protect infants from RSV infection.
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Affiliation(s)
- Hirono Otomaru
- Department of Virology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Taro Kamigaki
- Department of Virology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Raita Tamaki
- Department of Life Creation, Nagasaki Women's Junior College, Japan
| | - Michiko Okamoto
- Department of Virology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | | | - Alvin Gue Tan
- Research Institute for Tropical Medicine, Metro Manila, Philippines
| | | | | | | | - Veronica Tallo
- Research Institute for Tropical Medicine, Metro Manila, Philippines
| | - Socorro Lupisan
- Research Institute for Tropical Medicine, Metro Manila, Philippines
| | - Hitoshi Oshitani
- Department of Virology, Tohoku University Graduate School of Medicine, Sendai, Japan
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64
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Hardelid P, Verfuerden M, McMenamin J, Smyth RL, Gilbert R. The contribution of child, family and health service factors to respiratory syncytial virus (RSV) hospital admissions in the first 3 years of life: birth cohort study in Scotland, 2009 to 2015. EURO SURVEILLANCE : BULLETIN EUROPEEN SUR LES MALADIES TRANSMISSIBLES = EUROPEAN COMMUNICABLE DISEASE BULLETIN 2019. [PMID: 30621817 DOI: 10.2807/1560‐7917.es.2019.24.1.1800046] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
IntroductionSeveral vaccines for respiratory syncytial virus (RSV) are under development. Designing an effective vaccination programme for RSV requires information about the relative contribution of risk factors for severe RSV symptoms.AimTo inform preventive strategies in Europe by quantifying the contribution of key child, family and health service risk factors to the burden of RSV hospital admissions in young children.MethodsWe constructed a birth cohort study of all singleton children born in Scotland between October 2009 and September 2012 using linkage between birth registration, maternity, vaccination and hospital admission records, with follow-up until the age of 3 years. RSV-confirmed hospital admissions were defined using linkage to national laboratory surveillance data. We estimated hospital admission rates per 1,000 child years and length of stay according to each risk factor. Cox proportional hazard regression models were used to estimate adjusted hazard ratios.ResultsThere were 5,185 RSV admissions among the 169,726 children in the cohort: 48.6% of admissions occurred before the age of 6 months, and 29.6% after the age of 1 year. Children born prematurely, small for gestational age, between July and December, with chronic conditions, older siblings, mothers < 30 years old or delayed infant vaccination had a significantly increased risk of admission. Minimising the risk posed by older siblings could reduce RSV admissions by up to 34%.ConclusionFuture RSV vaccination programmes must protect children throughout early childhood. Vaccination and/or interventions to reduce transmission by older siblings could substantially reduce RSV hospital admissions.
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Affiliation(s)
- Pia Hardelid
- UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | | | | | - Rosalind L Smyth
- UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Ruth Gilbert
- UCL Great Ormond Street Institute of Child Health, London, United Kingdom
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Pandolfi E, Gesualdo F, Rizzo C, Carloni E, Villani A, Concato C, Linardos G, Russo L, Ferretti B, Campagna I, Tozzi A. Breastfeeding and Respiratory Infections in the First 6 Months of Life: A Case Control Study. Front Pediatr 2019; 7:152. [PMID: 31106183 PMCID: PMC6492465 DOI: 10.3389/fped.2019.00152] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 04/01/2019] [Indexed: 12/02/2022] Open
Abstract
Background: Viral respiratory tract infections (VRI) are a major reason for hospitalization in children younger than 5 years. A case control study was conducted to investigate the potential role of breastfeeding in protecting children <1 year of age from VRI. Methods: Patients admitted for a respiratory tract infections routinely underwent a nasopharyngeal aspirate, which was tested with an RT-PCR for 14 respiratory viruses. Hospitalized infants positive for viruses were enrolled as cases; healthy controls were enrolled among patients admitted for ultrasound hip screening. The effect of breastfeeding on pertussis was investigated through multivariable analysis. Results: We enrolled a total of 496 patients: 238 cases and 258 healthy controls. Among cases, eighty-six patients (36.1%) had a rinovirus, 78 (32.8%) an RSV, 22 (9.2%) an adenovirus, and 37 (15.5%) a coinfections with multiple viruses. The number of households was significantly higher in cases (mean in cases 4.5; mean 3.7 in controls, p < 0.001) and the proportion of infants having siblings (79% in cases vs. 43% in controls, p < 0.001). Proportion of smoking mothers was higher in cases than in controls (21.4 vs. 10.1%, p = 0.001). Among cases 44.5% were exclusively breastfed at symptoms onset vs. 48.8% of healthy controls. According to the multivariable analysis, being exclusively breastfed at symptom onset was associated with a higher risk of viral respiratory infection (3.7; 95% CI 1.64-8.41), however a longer breastfeeding duration was protective (OR 0.98; 95% CI 0.97-0.99). Also having at least one sibling was associated to a higher risk (OR 3.6; 95% CI 2.14-5.92) as well as having a smoking mother (OR 2.6; 95% CI 1.33-4.89). Conclusions: Breastfeeding remains a mainstay of prevention for numerous diseases and its protective role increases with duration. However, being breastfed when mothers carry a respiratory infection may increase the risk of transmission, acting as a proxy for closer contacts. In future studies, potential confounding variables as pattern of contacts with other individuals, should be taken into account.
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Affiliation(s)
- Elisabetta Pandolfi
- Multifactorial Disease and Complex Phenotype Research Area, Bambino Gesù Children's Hospital (IRCCS), Rome, Italy
| | - Francesco Gesualdo
- Multifactorial Disease and Complex Phenotype Research Area, Bambino Gesù Children's Hospital (IRCCS), Rome, Italy
| | - Caterina Rizzo
- Multifactorial Disease and Complex Phenotype Research Area, Bambino Gesù Children's Hospital (IRCCS), Rome, Italy
| | - Emanuela Carloni
- Multifactorial Disease and Complex Phenotype Research Area, Bambino Gesù Children's Hospital (IRCCS), Rome, Italy
| | - Alberto Villani
- Department of Pediatrics, Bambino Gesù Children's Hospital (IRCCS), Rome, Italy
| | - Carlo Concato
- Virology Unit, Laboratory Department, Bambino Gesù Children's Hospital (IRCCS), Rome, Italy
| | - Giulia Linardos
- Multifactorial Disease and Complex Phenotype Research Area, Bambino Gesù Children's Hospital (IRCCS), Rome, Italy
| | - Luisa Russo
- Multifactorial Disease and Complex Phenotype Research Area, Bambino Gesù Children's Hospital (IRCCS), Rome, Italy
| | - Beatrice Ferretti
- Multifactorial Disease and Complex Phenotype Research Area, Bambino Gesù Children's Hospital (IRCCS), Rome, Italy
| | - Ilaria Campagna
- Multifactorial Disease and Complex Phenotype Research Area, Bambino Gesù Children's Hospital (IRCCS), Rome, Italy
| | - Alberto Tozzi
- Multifactorial Disease and Complex Phenotype Research Area, Bambino Gesù Children's Hospital (IRCCS), Rome, Italy
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Who interacts with whom? Social mixing insights from a rural population in India. PLoS One 2018; 13:e0209039. [PMID: 30576333 PMCID: PMC6303083 DOI: 10.1371/journal.pone.0209039] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 11/27/2018] [Indexed: 11/19/2022] Open
Abstract
Acute lower respiratory infections (ALRI) are a leading cause of morbidity and mortality globally, with most ALRI deaths occurring in children in developing countries. Computational models can be used to test the efficacy of respiratory infection prevention interventions, but require data on social mixing patterns, which are sparse in developing countries. We describe social mixing patterns among a rural community in northern India. During October 2015-February 2016, trained field workers conducted cross-sectional face-to-face standardized surveys in a convenience sample of 330 households in Faridabad District, Haryana State, India. Respondents were asked about the number, duration, and setting of social interactions during the previous 24 hours. Responses were compared by age and gender. Among the 3083 residents who were approached, 2943 (96%) participated, of whom 51% were male and the median age was 22 years (interquartile range (IQR) 9–37). Respondents reported contact (defined as having had a face-to-face conversation within 3 feet, which may or may not have included physical contact) with a median of 17 (IQR 12–25) people during the preceding 24 hours. Median total contact time per person was 36 person-hours (IQR 26–52). Female older children and adults had significantly fewer contacts than males of similar age (Kruskal-Wallis χ2 = 226.59, p<0.001), but spent a longer duration in contact with young children (Kruskal-Wallis χ2 = 27.26, p<0.001), suggesting a potentially complex pattern of differential risk of infection between genders. After controlling for household size and day of the week, respondent age was significantly associated with number and duration of contacts. These findings can be used to model the impact of interventions to reduce lower respiratory tract infections in India.
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67
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Morpeth SC, Munywoki P, Hammitt LL, Bett A, Bottomley C, Onyango CO, Murdoch DR, Nokes DJ, Scott JAG. Impact of viral upper respiratory tract infection on the concentration of nasopharyngeal pneumococcal carriage among Kenyan children. Sci Rep 2018; 8:11030. [PMID: 30038420 PMCID: PMC6056465 DOI: 10.1038/s41598-018-29119-w] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 07/02/2018] [Indexed: 01/08/2023] Open
Abstract
Viral upper respiratory tract infection (URTI) predisposes to bacterial pneumonia possibly by facilitating growth of bacteria such as Streptococcus pneumoniae colonising the nasopharynx. We investigated whether viral URTI is temporally associated with an increase in nasopharyngeal pneumococcal concentration. Episodes of symptomatic RSV or rhinovirus URTI among children <5 years were identified from a longitudinal household study in rural Kenya. lytA and alu PCR were performed on nasopharyngeal samples collected twice-weekly, to measure the pneumococcal concentration adjusted for the concentration of human DNA present. Pneumococcal concentration increased with a fold-change of 3.80 (95%CI 1.95-7.40), with acquisition of RSV or rhinovirus, during 51 URTI episodes among 42 children. In repeated swabs from the baseline period, in the two weeks before URTI developed, within-episode variation was broad; within +/-112-fold range of the geometric mean. We observed only a small increase in nasopharyngeal pneumococcal concentration during RSV or rhinovirus URTI, relative to natural variation. Other factors, such as host response to viral infection, may be more important than nasopharyngeal pneumococcal concentration in determining risk of invasive disease.
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Affiliation(s)
- Susan C Morpeth
- KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya.
- Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7FZ, United Kingdom.
- Department of Infectious Disease Epidemiology, the London School of Hygiene and Tropical Medicine, London, WC1E 7HT, United Kingdom.
- Microbiology Laboratory, Middlemore Hospital, Counties Manukau District Health Board, Private Bag 93311, Otahuhu, Auckland, 1640, New Zealand.
| | | | - Laura L Hammitt
- KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, 21205, USA
| | - Anne Bett
- KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
| | - Christian Bottomley
- Department of Infectious Disease Epidemiology, the London School of Hygiene and Tropical Medicine, London, WC1E 7HT, United Kingdom
| | - Clayton O Onyango
- KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
- Kenya Medical Research Institute (KEMRI), Centre for Global Health Research; KEMRI - CGHR, Kisumu, Kenya
| | - David R Murdoch
- Department of Pathology, University of Otago, Christchurch, New Zealand
- Microbiology Unit, Canterbury Health Laboratories, Christchurch, 8011, New Zealand
| | - D James Nokes
- KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
- School of Life Sciences and Zeeman Institute (SBIDER), University of Warwick, Coventry, CV4 7AL, United Kingdom
| | - J Anthony G Scott
- KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
- Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7FZ, United Kingdom
- Department of Infectious Disease Epidemiology, the London School of Hygiene and Tropical Medicine, London, WC1E 7HT, United Kingdom
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68
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Blanco JCG, Boukhvalova MS, Morrison TG, Vogel SN. A multifaceted approach to RSV vaccination. Hum Vaccin Immunother 2018; 14:1734-1745. [PMID: 29771625 PMCID: PMC6067850 DOI: 10.1080/21645515.2018.1472183] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 04/12/2018] [Accepted: 04/29/2018] [Indexed: 12/15/2022] Open
Abstract
Respiratory Syncytial Virus (RSV) is the leading cause of pneumonia and bronchiolitis in infants, resulting in significant morbidity and mortality worldwide. In addition, RSV infections occur throughout different ages, thus, maintaining the virus in circulation, and increasing health risk to more susceptible populations such as infants, the elderly, and the immunocompromised. To date, there is no vaccine approved to prevent RSV infection or minimize symptoms of infection. Current clinical trials for vaccines against RSV are being carried out in four very different populations. There are vaccines that target two different pediatric populations, infants 2 to 6 month of age and seropositive children over 6 months of age, as well as women (non-pregnant or pregnant in their third trimester). There are vaccines that target adult and elderly populations. In this review, we will present and discuss RSV vaccine candidates currently in clinical trials. We will describe the preclinical studies instrumental for their advancement, with the goal of introducing new preclinical models that may more accurately predict the outcome of clinical vaccine studies.
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69
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Kiyuka PK, Agoti CN, Munywoki PK, Njeru R, Bett A, Otieno JR, Otieno GP, Kamau E, Clark TG, van der Hoek L, Kellam P, Nokes DJ, Cotten M. Human Coronavirus NL63 Molecular Epidemiology and Evolutionary Patterns in Rural Coastal Kenya. J Infect Dis 2018; 217:1728-1739. [PMID: 29741740 PMCID: PMC6037089 DOI: 10.1093/infdis/jiy098] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 02/27/2018] [Indexed: 11/13/2022] Open
Abstract
Background Human coronavirus NL63 (HCoV-NL63) is a globally endemic pathogen causing mild and severe respiratory tract infections with reinfections occurring repeatedly throughout a lifetime. Methods Nasal samples were collected in coastal Kenya through community-based and hospital-based surveillance. HCoV-NL63 was detected with multiplex real-time reverse transcription PCR, and positive samples were targeted for nucleotide sequencing of the spike (S) protein. Additionally, paired samples from 25 individuals with evidence of repeat HCoV-NL63 infection were selected for whole-genome virus sequencing. Results HCoV-NL63 was detected in 1.3% (75/5573) of child pneumonia admissions. Two HCoV-NL63 genotypes circulated in Kilifi between 2008 and 2014. Full genome sequences formed a monophyletic clade closely related to contemporary HCoV-NL63 from other global locations. An unexpected pattern of repeat infections was observed with some individuals showing higher viral titers during their second infection. Similar patterns for 2 other endemic coronaviruses, HCoV-229E and HCoV-OC43, were observed. Repeat infections by HCoV-NL63 were not accompanied by detectable genotype switching. Conclusions In this coastal Kenya setting, HCoV-NL63 exhibited low prevalence in hospital pediatric pneumonia admissions. Clade persistence with low genetic diversity suggest limited immune selection, and absence of detectable clade switching in reinfections indicates initial exposure was insufficient to elicit a protective immune response.
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Affiliation(s)
- Patience K Kiyuka
- Epidemiology and Demography Department, Kenya Medical Research Institute-Wellcome Trust Research Programme
| | - Charles N Agoti
- Epidemiology and Demography Department, Kenya Medical Research Institute-Wellcome Trust Research Programme
- School of Health and Human Sciences, Pwani University, Kilifi, Kenya
| | - Patrick K Munywoki
- Epidemiology and Demography Department, Kenya Medical Research Institute-Wellcome Trust Research Programme
| | - Regina Njeru
- Epidemiology and Demography Department, Kenya Medical Research Institute-Wellcome Trust Research Programme
| | - Anne Bett
- Epidemiology and Demography Department, Kenya Medical Research Institute-Wellcome Trust Research Programme
| | - James R Otieno
- Epidemiology and Demography Department, Kenya Medical Research Institute-Wellcome Trust Research Programme
| | - Grieven P Otieno
- Epidemiology and Demography Department, Kenya Medical Research Institute-Wellcome Trust Research Programme
| | - Everlyn Kamau
- Epidemiology and Demography Department, Kenya Medical Research Institute-Wellcome Trust Research Programme
| | - Taane G Clark
- Faculty of Infectious and Tropical Diseases, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Lia van der Hoek
- Laboratory of Experimental Virology, Academic Medical Center of the University of Amsterdam, the Netherlands
| | - Paul Kellam
- Department of Medicine, Division of Infectious Diseases, Imperial College London
- Kymab Ltd., Babraham Research Campus, Cambridge
| | - D James Nokes
- Epidemiology and Demography Department, Kenya Medical Research Institute-Wellcome Trust Research Programme
- School of Life Sciences and Zeeman Institute, University of Warwick, Coventry
| | - Matthew Cotten
- Wellcome Trust Sanger Institute, Hinxton, United Kingdom
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70
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Kinyanjui T, Middleton J, Güttel S, Cassell J, Ross J, House T. Scabies in residential care homes: Modelling, inference and interventions for well-connected population sub-units. PLoS Comput Biol 2018; 14:e1006046. [PMID: 29579037 PMCID: PMC5898763 DOI: 10.1371/journal.pcbi.1006046] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 04/13/2018] [Accepted: 02/20/2018] [Indexed: 12/03/2022] Open
Abstract
In the context of an ageing population, understanding the transmission of infectious diseases such as scabies through well-connected sub-units of the population, such as residential care homes, is particularly important for the design of efficient interventions to mitigate against the effects of those diseases. Here, we present a modelling methodology based on the efficient solution of a large-scale system of linear differential equations that allows statistical calibration of individual-based random models to real data on scabies in residential care homes. In particular, we review and benchmark different numerical methods for the integration of the differential equation system, and then select the most appropriate of these methods to perform inference using Markov chain Monte Carlo. We test the goodness-of-fit of this model using posterior predictive intervals and propagate forward the resulting parameter uncertainty in a Bayesian framework to consider the economic cost of delayed interventions against scabies, quantifying the benefits of prompt action in the event of detection. We also revisit the previous methodology used to assess the safety of treatments in small population sub-units-in this context ivermectin-and demonstrate that even a very slight relaxation of the implicit assumption of homogeneous death rates significantly increases the plausibility of the hypothesis that ivermectin does not cause excess mortality based upon the data of Barkwell and Shields.
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Affiliation(s)
| | - Jo Middleton
- Department of Primary Care and Public Health Medicine, Brighton and Sussex Medical School, Falmer, Brighton, United Kingdom
| | - Stefan Güttel
- School of Mathematics, University of Manchester, United Kingdom
| | - Jackie Cassell
- Department of Primary Care and Public Health Medicine, Brighton and Sussex Medical School, Falmer, Brighton, United Kingdom
| | - Joshua Ross
- School of Mathematical Sciences, The University of Adelaide, Adelaide, Australia
| | - Thomas House
- School of Mathematics, University of Manchester, United Kingdom
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71
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Hogan AB, Campbell PT, Blyth CC, Lim FJ, Fathima P, Davis S, Moore HC, Glass K. Potential impact of a maternal vaccine for RSV: A mathematical modelling study. Vaccine 2017; 35:6172-6179. [PMID: 28967522 DOI: 10.1016/j.vaccine.2017.09.043] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 08/14/2017] [Accepted: 09/13/2017] [Indexed: 11/16/2022]
Abstract
Respiratory syncytial virus (RSV) is a major cause of respiratory morbidity and one of the main causes of hospitalisation in young children. While there is currently no licensed vaccine for RSV, a vaccine candidate for pregnant women is undergoing phase 3 trials. We developed a compartmental age-structured model for RSV transmission, validated using linked laboratory-confirmed RSV hospitalisation records for metropolitan Western Australia. We adapted the model to incorporate a maternal RSV vaccine, and estimated the expected reduction in RSV hospitalisations arising from such a program. The introduction of a vaccine was estimated to reduce RSV hospitalisations in Western Australia by 6-37% for 0-2month old children, and 30-46% for 3-5month old children, for a range of vaccine effectiveness levels. Our model shows that, provided a vaccine is demonstrated to extend protection against RSV disease beyond the first three months of life, a policy using a maternal RSV vaccine could be effective in reducing RSV hospitalisations in children up to six months of age, meeting the objective of a maternal vaccine in delaying an infant's first RSV infection to an age at which severe disease is less likely.
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Affiliation(s)
- Alexandra B Hogan
- Research School of Population Health, The Australian National University, 62 Mills Rd, The Australian National University, Acton ACT 2601, Australia.
| | - Patricia T Campbell
- Doherty Epidemiology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Level 5, 792 Elizabeth St, Melbourne, Victoria 3000, Australia; Infection and Immunity, Murdoch Childrens Research Institute, Royal Children's Hospital, Flemington Rd, Parkville 3052, Victoria, Australia
| | - Christopher C Blyth
- School of Medicine, University of Western Australia, Princess Margaret Hospital for Children, Roberts Rd, Subiaco, Perth, WA 6008, Australia; Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, 100 Roberts Rd, Subiaco, Perth, WA 6008, Australia; Department of Infectious Disease and PathWest Department of Microbiology, Princess Margaret Hospital for Children, Roberts Rd, Subiaco, WA 6008, Australia
| | - Faye J Lim
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, 100 Roberts Rd, Subiaco, Perth, WA 6008, Australia
| | - Parveen Fathima
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, 100 Roberts Rd, Subiaco, Perth, WA 6008, Australia
| | - Stephanie Davis
- Research School of Population Health, The Australian National University, 62 Mills Rd, The Australian National University, Acton ACT 2601, Australia
| | - Hannah C Moore
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, 100 Roberts Rd, Subiaco, Perth, WA 6008, Australia
| | - Kathryn Glass
- Research School of Population Health, The Australian National University, 62 Mills Rd, The Australian National University, Acton ACT 2601, Australia
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72
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Agoti CN, Munywoki PK, Phan MVT, Otieno JR, Kamau E, Bett A, Kombe I, Githinji G, Medley GF, Cane PA, Kellam P, Cotten M, Nokes DJ. Transmission patterns and evolution of respiratory syncytial virus in a community outbreak identified by genomic analysis. Virus Evol 2017; 3:vex006. [PMID: 28458916 PMCID: PMC5399923 DOI: 10.1093/ve/vex006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Detailed information on the source, spread and evolution of respiratory syncytial virus (RSV) during seasonal community outbreaks remains sparse. Molecular analyses of attachment (G) gene sequences from hospitalized cases suggest that multiple genotypes and variants co-circulate during epidemics and that RSV persistence over successive seasons is characterized by replacement and multiple new introductions of variants. No studies have defined the patterns of introduction, spread and evolution of RSV at the local community and household level. We present a whole genome sequence analysis of 131 RSV group A viruses collected during 6-month household-based RSV infection surveillance in Coastal Kenya, 2010 within an area of 12 km2. RSV infections were identified by regular symptom-independent screening of all household members twice weekly. Phylogenetic analysis revealed that the RSV A viruses in nine households were closely related to genotype GA2 and fell within a single branch of the global phylogeny. Genomic analysis allowed the detection of household-specific variation in seven households. For comparison, using only G gene analysis, household-specific variation was found only in one of the nine households. Nucleotide changes were observed both intra-host (viruses identified from same individual in follow-up sampling) and inter-host (viruses identified from different household members) and these coupled with sampling dates enabled a partial reconstruction of the within household transmission chains. The genomic evolutionary rate for the household dataset was estimated as 2.307 × 10 − 3 (95% highest posterior density: 0.935–4.165× 10 − 3) substitutions/site/year. We conclude that (i) at the household level, most RSV infections arise from the introduction of a single virus variant followed by accumulation of household specific variation and (ii) analysis of complete virus genomes is crucial to better understand viral transmission in the community. A key question arising is whether prevention of RSV introduction or spread within the household by vaccinating key transmitting household members would lead to a reduced onward community-wide transmission.
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Affiliation(s)
- Charles N Agoti
- Epidemiology and Demography Department, Kenya Medical Research Institute (KEMRI) - Wellcome Trust Research Collaborative Programme, Kilifi, Kenya.,School of Health and Human Sciences, Pwani University, Kilifi, Kenya
| | - Patrick K Munywoki
- Epidemiology and Demography Department, Kenya Medical Research Institute (KEMRI) - Wellcome Trust Research Collaborative Programme, Kilifi, Kenya.,School of Health and Human Sciences, Pwani University, Kilifi, Kenya
| | - My V T Phan
- The Wellcome Trust Sanger Institute, Cambridge, UK.,Virosciences Department, Erasmus Medical Center, Rotterdam, The Netherlands
| | - James R Otieno
- Epidemiology and Demography Department, Kenya Medical Research Institute (KEMRI) - Wellcome Trust Research Collaborative Programme, Kilifi, Kenya
| | - Everlyn Kamau
- Epidemiology and Demography Department, Kenya Medical Research Institute (KEMRI) - Wellcome Trust Research Collaborative Programme, Kilifi, Kenya
| | - Anne Bett
- Epidemiology and Demography Department, Kenya Medical Research Institute (KEMRI) - Wellcome Trust Research Collaborative Programme, Kilifi, Kenya
| | - Ivy Kombe
- Epidemiology and Demography Department, Kenya Medical Research Institute (KEMRI) - Wellcome Trust Research Collaborative Programme, Kilifi, Kenya
| | - George Githinji
- Epidemiology and Demography Department, Kenya Medical Research Institute (KEMRI) - Wellcome Trust Research Collaborative Programme, Kilifi, Kenya
| | - Graham F Medley
- Department of Global Health and Development, London School of Hygiene and Tropical Medicine, London, UK
| | - Patricia A Cane
- Virus Reference Department, Public Health England, London, UK
| | - Paul Kellam
- The Wellcome Trust Sanger Institute, Cambridge, UK.,Department of Infectious Diseases and Immunity, Imperial College London, London, UK
| | - Matthew Cotten
- The Wellcome Trust Sanger Institute, Cambridge, UK.,Virosciences Department, Erasmus Medical Center, Rotterdam, The Netherlands
| | - D James Nokes
- Epidemiology and Demography Department, Kenya Medical Research Institute (KEMRI) - Wellcome Trust Research Collaborative Programme, Kilifi, Kenya.,School of Life Sciences and WIDER, University of Warwick, Coventry, UK
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73
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Keeling MJ, House T, Cooper AJ, Pellis L. Systematic Approximations to Susceptible-Infectious-Susceptible Dynamics on Networks. PLoS Comput Biol 2016; 12:e1005296. [PMID: 27997542 PMCID: PMC5283726 DOI: 10.1371/journal.pcbi.1005296] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 01/31/2017] [Accepted: 12/09/2016] [Indexed: 11/20/2022] Open
Abstract
Network-based infectious disease models have been highly effective in elucidating the role of contact structure in the spread of infection. As such, pair- and neighbourhood-based approximation models have played a key role in linking findings from network simulations to standard (random-mixing) results. Recently, for SIR-type infections (that produce one epidemic in a closed population) on locally tree-like networks, these approximations have been shown to be exact. However, network models are ideally suited for Sexually Transmitted Infections (STIs) due to the greater level of detail available for sexual contact networks, and these diseases often possess SIS-type dynamics. Here, we consider the accuracy of three systematic approximations that can be applied to arbitrary disease dynamics, including SIS behaviour. We focus in particular on low degree networks, in which the small number of neighbours causes build-up of local correlations between the state of adjacent nodes that are challenging to capture. By examining how and when these approximation models converge to simulation results, we generate insights into the role of network structure in the infection dynamics of SIS-type infections. Networks are now widely used to model infectious diseases, but have posed significant mathematical challenges. Recently analytic results have been obtained for ‘one-off’ network epidemics that follow the SIR paradigm, but these results do not carry over to other scenarios—most significantly to many sexually transmitted infections, where accounting for network structure is vital. Here, we show that it is possible to obtain the large-population dynamics of such diseases on networks through systematic approximations. We focus on a mathematically challenging case of SIS dynamics on networks with low degree.
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Affiliation(s)
- Matt J. Keeling
- Zeeman Institute: SBIDER, University of Warwick, Coventry, United Kingdom
- Mathematics Institute, University of Warwick, Coventry, United Kingdom
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
- * E-mail:
| | - Thomas House
- Zeeman Institute: SBIDER, University of Warwick, Coventry, United Kingdom
- Mathematics Institute, University of Warwick, Coventry, United Kingdom
- School of Mathematics, University of Manchester, Manchester, United Kingdom
| | - Alison J. Cooper
- School of Engineering, University of Warwick, Coventry, United Kingdom
| | - Lorenzo Pellis
- Zeeman Institute: SBIDER, University of Warwick, Coventry, United Kingdom
- Mathematics Institute, University of Warwick, Coventry, United Kingdom
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Wathuo M, Medley GF, Nokes D, Munywoki PK. Quantification and determinants of the amount of respiratory syncytial virus (RSV) shed using real time PCR data from a longitudinal household study. Wellcome Open Res 2016. [DOI: 10.12688/wellcomeopenres.10284.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Background: A better understanding of respiratory syncytial virus (RSV) epidemiology requires realistic estimates of RSV shedding patterns, quantities shed, and identification of the related underlying factors. Methods: RSV infection data arise from a cohort study of 47 households with 493 occupants, in coastal Kenya, during the 2009/2010 RSV season. Nasopharyngeal swabs were taken every 3 to 4 days and screened for RSV using a real time polymerase chain reaction (PCR) assay. The amount of virus shed was quantified by calculating the ‘area under the curve’ using the trapezoidal rule applied to rescaled PCR cycle threshold output. Multivariable linear regression was used to identify correlates of amount of virus shed. Results: The median quantity of virus shed per infection episode was 29.4 (95% CI: 15.2, 54.2) log10 ribonucleic acid (RNA) copies. Young age (<1 year), presence of upper respiratory symptoms, intra-household acquisition of infection, an individual’s first infection episode in the RSV season, and having a co-infection of RSV group A and B were associated with increased amount of virus shed. Conclusions: The findings provide insight into which groups of individuals have higher potential for transmission, information which may be useful in designing RSV prevention strategies.
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75
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Wathuo M, Medley GF, Nokes DJ, Munywoki PK. Quantification and determinants of the amount of respiratory syncytial virus (RSV) shed using real time PCR data from a longitudinal household study. Wellcome Open Res 2016; 1:27. [PMID: 28066826 PMCID: PMC5218551 DOI: 10.12688/wellcomeopenres.10284.2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Background A better understanding of respiratory syncytial virus (RSV) epidemiology requires realistic estimates of RSV shedding patterns, quantities shed, and identification of the related underlying factors. Methods RSV infection data arise from a cohort study of 47 households with 493 occupants, in coastal Kenya, during the 2009/2010 RSV season. Nasopharyngeal swabs were taken every 3 to 4 days and screened for RSV using a real time polymerase chain reaction (PCR) assay. The amount of virus shed was quantified by calculating the 'area under the curve' using the trapezoidal rule applied to rescaled PCR cycle threshold output. Multivariable linear regression was used to identify correlates of amount of virus shed. Results The median quantity of virus shed per infection episode was 29.4 (95% CI: 15.2, 54.2) log10 ribonucleic acid (RNA) copies. Young age (<1 year), presence of upper respiratory symptoms, intra-household acquisition of infection, an individual's first infection episode in the RSV season, and having a co-infection of RSV group A and B were associated with increased amount of virus shed. Conclusions The findings provide insight into which groups of individuals have higher potential for transmission, information which may be useful in designing RSV prevention strategies.
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Affiliation(s)
- Miriam Wathuo
- KEMRI - Wellcome Trust Research Programme, Centre for Geographic Medicine Research - Coast, Kilifi, Kenya
| | - Graham F Medley
- Department of Global Health and Development, London School of Hygiene and Tropical Medicine, London, UK
| | - D James Nokes
- KEMRI - Wellcome Trust Research Programme, Centre for Geographic Medicine Research - Coast, Kilifi, Kenya.,School of Life Sciences and SBIDER, University of Warwick, Coventry, UK
| | - Patrick K Munywoki
- KEMRI - Wellcome Trust Research Programme, Centre for Geographic Medicine Research - Coast, Kilifi, Kenya.,Department of Nursing Sciences, Pwani University, Kilifi, Kenya
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76
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Characterizing the risk of respiratory syncytial virus in infants with older siblings: a population-based birth cohort study. Epidemiol Infect 2016; 145:266-271. [PMID: 27821195 DOI: 10.1017/s0950268816002545] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
From a population-based birth cohort of 245 249 children born in Western Australia during 1996-2005, we used linkage of laboratory and birth record datasets to obtain data including all respiratory syncytial virus (RSV) detections during infancy from a subcohort of 87 981 singleton children born in the Perth metropolitan area from 2000 to 2004. Using log binomial regression, we found that the risk of infant RSV detection increases with the number of older siblings, with those having ⩾3 older siblings experiencing almost three times the risk (relative risk 2·83, 95% confidence interval 2·46-3·26) of firstborn children. We estimate that 45% of the RSV detections in our subcohort were attributable to infection from an older sibling. The sibling effect was significantly higher for those infants who were younger during the season of peak risk (winter) than those who were older. Although older siblings were present in our cohort, they had very few RSV detections which could be temporally linked to an infant's infection. We conclude that RSV infection in older children leads to less severe symptoms but is nevertheless an important source of infant infection. Our results lend support to a vaccination strategy which includes family members in order to provide maximum protection for newborn babies.
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77
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Simões EAF. The Outpatient Burden of Respiratory Syncytial Virus Infections in Older Children. J Infect Dis 2016; 215:1-3. [DOI: 10.1093/infdis/jiw483] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 10/03/2016] [Indexed: 12/24/2022] Open
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78
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Heikkinen T, Ojala E, Waris M. Clinical and Socioeconomic Burden of Respiratory Syncytial Virus Infection in Children. J Infect Dis 2016; 215:17-23. [PMID: 27738052 DOI: 10.1093/infdis/jiw475] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 08/18/2016] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Vaccines and antivirals against respiratory syncytial virus (RSV) are being developed, but there are scarce data on the full impact of RSV infection on outpatient children. METHODS We analyzed the burden of RSV illness in a prospective cohort study of children aged ≤13 years during 2 consecutive respiratory seasons in Turku, Finland (2231 child-seasons of follow-up). We examined the children and obtained nasal swabs for the detection of RSV during each respiratory illness. The parents filled out daily symptom diaries throughout the study. RESULTS Of 6001 medically attended respiratory infections, 302 (5%) were caused by RSV. Per 1000 children, the average annual RSV infection incidence rates among children aged <3, 3-6, and 7-13 years were 275, 117, and 46 cases, respectively. In children aged <3 years, acute otitis media developed in 58%, and 66% of children in this age group received antibiotics. The mean duration of RSV illness was longest (13.0 days) and the rate of parental work absenteeism was highest (136 days per 100 children with RSV illness) in children aged <3 years. CONCLUSIONS The burden of RSV is particularly great among outpatient children aged <3 years. Young children are an important target group for the development of RSV vaccines and antivirals.
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Affiliation(s)
- Terho Heikkinen
- Department of Pediatrics, University of Turku and Turku University Hospital
| | - Emilia Ojala
- Department of Pediatrics, University of Turku and Turku University Hospital
| | - Matti Waris
- Department of Virology, University of Turku, Finland
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79
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Abstract
Primer-independent agnostic deep sequencing was used to generate three human rhinovirus (HRV) B genomes and one HRV C genome from samples collected in a household respiratory survey in rural coastal Kenya. The study provides the first rhinovirus genomes from Kenya and will help improve the sensitivity of local molecular diagnostics.
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80
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Desale M, Thinkhamrop J, Lumbiganon P, Qazi S, Anderson J. Ending preventable maternal and newborn deaths due to infection. Best Pract Res Clin Obstet Gynaecol 2016; 36:116-130. [PMID: 27450868 DOI: 10.1016/j.bpobgyn.2016.05.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 05/29/2016] [Accepted: 05/31/2016] [Indexed: 01/01/2023]
Abstract
Over 300,000 maternal deaths occur each year, 11% of which are thought to be due to infectious causes, and approximately one million newborns die within the first week of life annually due to infectious causes. Infections in pregnancy may result in a variety of adverse obstetrical outcomes, including preterm delivery, pre-labor rupture of membranes, stillbirth, spontaneous abortion, congenital infection, and anomalies. This paper reviews the burden of disease due to key infections and their contribution to maternal, perinatal, and newborn morbidity and mortality, as well as key interventions to prevent maternal and newborn deaths related to these infections. Research needs include more accurate clinical and microbiologic surveillance systems, validated risk stratification strategies, better point-of-care testing, and identification of promising vaccine strategies.
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Affiliation(s)
- Meghana Desale
- Johns Hopkins University, Phipps 247, 600 N. Wolfe St., Baltimore, MD 21287, USA.
| | - Jadsada Thinkhamrop
- Department of Obstetrics and Gynaecology, Khon Kaen University, Khon Kaen, 40002 Thailand.
| | - Pisake Lumbiganon
- Department of Obstetrics and Gynaecology, Khon Kaen University, Khon Kaen, 40002 Thailand.
| | - Shamim Qazi
- Department of Maternal, Newborn, Child and Adolescent Health, World Health Organization, 20 Avenue Appia, Geneva, 27 1211, Switzerland.
| | - Jean Anderson
- Johns Hopkins University, Phipps 247, 600 N. Wolfe St., Baltimore, MD 21287, USA.
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81
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Kiti MC, Tizzoni M, Kinyanjui TM, Koech DC, Munywoki PK, Meriac M, Cappa L, Panisson A, Barrat A, Cattuto C, Nokes DJ. Quantifying social contacts in a household setting of rural Kenya using wearable proximity sensors. EPJ DATA SCIENCE 2016; 5:21. [PMID: 27471661 PMCID: PMC4944592 DOI: 10.1140/epjds/s13688-016-0084-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 06/06/2016] [Indexed: 06/06/2023]
Abstract
UNLABELLED Close proximity interactions between individuals influence how infections spread. Quantifying close contacts in developing world settings, where such data is sparse yet disease burden is high, can provide insights into the design of intervention strategies such as vaccination. Recent technological advances have enabled collection of time-resolved face-to-face human contact data using radio frequency proximity sensors. The acceptability and practicalities of using proximity devices within the developing country setting have not been investigated. We present and analyse data arising from a prospective study of 5 households in rural Kenya, followed through 3 consecutive days. Pre-study focus group discussions with key community groups were held. All residents of selected households carried wearable proximity sensors to collect data on their close (<1.5 metres) interactions. Data collection for residents of three of the 5 households was contemporaneous. Contact matrices and temporal networks for 75 individuals are defined and mixing patterns by age and time of day in household contacts determined. Our study demonstrates the stability of numbers and durations of contacts across days. The contact durations followed a broad distribution consistent with data from other settings. Contacts within households occur mainly among children and between children and adults, and are characterised by daily regular peaks in the morning, midday and evening. Inter-household contacts are between adults and more sporadic when measured over several days. Community feedback indicated privacy as a major concern especially regarding perceptions of non-participants, and that community acceptability required thorough explanation of study tools and procedures. Our results show for a low resource setting how wearable proximity sensors can be used to objectively collect high-resolution temporal data without direct supervision. The methodology appears acceptable in this population following adequate community engagement on study procedures. A target for future investigation is to determine the difference in contact networks within versus between households. We suggest that the results from this study may be used in the design of future studies using similar electronic devices targeting communities, including households and schools, in the developing world context. ELECTRONIC SUPPLEMENTARY MATERIAL The online version of this article (doi:10.1140/epjds/s13688-016-0084-2) contains supplementary material.
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Affiliation(s)
- Moses C Kiti
- />KEMRI - Wellcome Trust Research Programme, Kilifi, Kenya
| | - Michele Tizzoni
- />Data Science Laboratory, ISI Foundation, Via Alassio 11/c, Torino, 10126 Italy
| | - Timothy M Kinyanjui
- />KEMRI - Wellcome Trust Research Programme, Kilifi, Kenya
- />School of Mathematics, The University of Manchester, Manchester, UK
| | | | | | | | - Luca Cappa
- />Data Science Laboratory, ISI Foundation, Via Alassio 11/c, Torino, 10126 Italy
| | - André Panisson
- />Data Science Laboratory, ISI Foundation, Via Alassio 11/c, Torino, 10126 Italy
| | - Alain Barrat
- />Data Science Laboratory, ISI Foundation, Via Alassio 11/c, Torino, 10126 Italy
- />Aix-Marseille Université, Université de Toulon, CNRS, CPT, UMR 7332, Marseille, 13288 France
| | - Ciro Cattuto
- />Data Science Laboratory, ISI Foundation, Via Alassio 11/c, Torino, 10126 Italy
| | - D James Nokes
- />KEMRI - Wellcome Trust Research Programme, Kilifi, Kenya
- />School of Life Sciences and WIDER, University of Warwick, Coventry, UK
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82
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Chu HY, Katz J, Tielsch J, Khatry SK, Shrestha L, LeClerq SC, Magaret A, Kuypers J, Steinhoff M, Englund JA. Respiratory syncytial virus infection in infants in rural Nepal. J Infect 2016; 73:145-54. [PMID: 27241525 PMCID: PMC4942356 DOI: 10.1016/j.jinf.2016.05.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 05/14/2016] [Accepted: 05/19/2016] [Indexed: 11/30/2022]
Abstract
Objectives Respiratory syncytial virus (RSV) pneumonia is a leading cause of infant mortality worldwide. The risk of RSV infection associated with preterm birth is not well-characterized in resource-limited settings. We aimed to obtain precise estimates of risk factors and disease burden of RSV in infants in rural southern Nepal. Methods Pregnant women were enrolled, and along with their infants, followed to six months after birth with active weekly home-based surveillance for acute respiratory illness (ARI). Mid-nasal swabs were obtained and tested for RSV by PCR for all illness episodes. Birth outcomes were assessed at a postpartum home visit. Results 311 (9%) of 3509 infants had an RSV ARI. RSV ARI incidence decreased from 551/1000 person-years in infants born between 28 and 31 weeks to 195/1000 person-years in infants born full-term (p = 0.017). Of 220 infants (71%) evaluated in the health system, 41 (19%) visited a hospital or physician. Of 287 infants with an assessment performed, 203 (71%) had a lower respiratory tract infection. Conclusions In a rural south Asian setting with intensive home-based surveillance, RSV caused a significant burden of respiratory illness. Preterm infants had the highest incidence of RSV ARI, and should be considered a priority group for RSV preventive interventions in resource-limited settings. RSV caused a significant burden of respiratory illness in infants in rural Nepal. The highest incidence of RSV was in preterm infants. Most infants with RSV had lower respiratory tract infection or a health care visit. Strategies are needed to prevent RSV in preterm infants in resource-limited settings.
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Affiliation(s)
- Helen Y Chu
- Department of Medicine, University of Washington, Seattle, WA, USA.
| | - Joanne Katz
- Department of International Health, Johns Hopkins University, Baltimore, MD, USA
| | - James Tielsch
- Department of Global Health, George Washington University, Washington, D.C., USA
| | - Subarna K Khatry
- Nepal Nutrition Intervention Project-Sarlahi, Sarlahi District, Nepal
| | - Laxman Shrestha
- Department of Pediatrics and Child Health, Institute of Medicine, Tribhuvan University, Kathmandu, Nepal
| | - Steven C LeClerq
- Nepal Nutrition Intervention Project-Sarlahi, Sarlahi District, Nepal
| | - Amalia Magaret
- Department of Laboratory Medicine, University of Washington, Seattle, WA, USA
| | - Jane Kuypers
- Department of Laboratory Medicine, University of Washington, Seattle, WA, USA
| | - Mark Steinhoff
- Department of Global Health, Cincinnati Children's Hospital, Cincinnati, OH, USA
| | - Janet A Englund
- Department of Pediatrics, University of Washington, Seattle Children's Research Institute, Seattle, WA, USA
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83
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Otieno JR, Agoti CN, Gitahi CW, Bett A, Ngama M, Medley GF, Cane PA, Nokes DJ. Molecular Evolutionary Dynamics of Respiratory Syncytial Virus Group A in Recurrent Epidemics in Coastal Kenya. J Virol 2016; 90:4990-5002. [PMID: 26937038 PMCID: PMC4859726 DOI: 10.1128/jvi.03105-15] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 02/25/2016] [Indexed: 11/23/2022] Open
Abstract
UNLABELLED The characteristic recurrent epidemics of human respiratory syncytial virus (RSV) within communities may result from the genetic variability of the virus and associated evolutionary adaptation, reducing the efficiency of preexisting immune responses. We analyzed the molecular evolutionary changes in the attachment (G) glycoprotein of RSV-A viruses collected over 13 epidemic seasons (2000 to 2012) in Kilifi (n = 649), Kenya, and contemporaneous sequences (n = 1,131) collected elsewhere within Kenya and 28 other countries. Genetic diversity in the G gene in Kilifi was dynamic both within and between epidemics, characterized by frequent new variant introductions and limited variant persistence between consecutive epidemics. Four RSV-A genotypes were detected in Kilifi: ON1 (11.9%), GA2 (75.5%), GA5 (12.3%), and GA3 (0.3%), with predominant genotype replacement of GA5 by GA2 and then GA2 by ON1. Within these genotypes, there was considerable variation in potential N-glycosylation sites, with GA2 and ON1 viruses showing up to 15 different patterns involving eight possible sites. Further, we identified 15 positively selected and 34 genotype-distinguishing codon sites, with six of these sites exhibiting both characteristics. The mean substitution rate of the G ectodomain for the Kilifi data set was estimated at 3.58 × 10(-3) (95% highest posterior density interval = 3.04 to 4.16) nucleotide substitutions/site/year. Kilifi viruses were interspersed in the global phylogenetic tree, clustering mostly with Kenyan and European sequences. Our findings highlight ongoing genetic evolution and high diversity of circulating RSV-A strains, locally and globally, with potential antigenic differences. Taken together, these provide a possible explanation on the nature of recurrent local RSV epidemics. IMPORTANCE The mechanisms underlying recurrent epidemics of RSV are poorly understood. We observe high genetic diversity in circulating strains within and between epidemics in both local and global settings. On longer time scales (∼7 years) there is sequential replacement of genotypes, whereas on shorter time scales (one epidemic to the next or within epidemics) there is a high turnover of variants within genotypes. Further, this genetic diversity is predicted to be associated with variation in antigenic profiles. These observations provide an explanation for recurrent RSV epidemics and have potential implications on the long-term effectiveness of vaccines.
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Affiliation(s)
- James R Otieno
- Epidemiology and Demography Department, Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Charles N Agoti
- Epidemiology and Demography Department, Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
- Department of Biomedical Sciences, Pwani University, Kilifi, Kenya
| | - Caroline W Gitahi
- Epidemiology and Demography Department, Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Ann Bett
- Epidemiology and Demography Department, Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Mwanajuma Ngama
- Epidemiology and Demography Department, Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Graham F Medley
- Department of Global Health and Development, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | - D James Nokes
- Epidemiology and Demography Department, Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
- School of Life Sciences and WIDER, University of Warwick, Coventry, United Kingdom
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84
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Graham BS. Vaccines against respiratory syncytial virus: The time has finally come. Vaccine 2016; 34:3535-41. [PMID: 27182820 DOI: 10.1016/j.vaccine.2016.04.083] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Revised: 04/11/2016] [Accepted: 04/15/2016] [Indexed: 11/27/2022]
Abstract
Respiratory syncytial virus causes a significant public health burden, particularly in very young infants and the frail elderly. The legacy of enhanced RSV disease (ERD) from a whole formalin-inactivated RSV vaccine, and the complex biology of the virus and the neonate have delayed the development of effective vaccines. However, new insights into factors associated with ERD and breakthroughs in understanding the antigenic structure of the fusion (F) glycoprotein have increased optimism that vaccine development is possible. This has led to investment of time and resources by industry, regulatory authorities, governments, and nonprofit organizations to develop the infrastructure needed to make the advanced clinical development of RSV vaccine candidates a reality.
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Affiliation(s)
- Barney S Graham
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States.
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85
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Hogan AB, Glass K, Moore HC, Anderssen RS. Exploring the dynamics of respiratory syncytial virus (RSV) transmission in children. Theor Popul Biol 2016; 110:78-85. [PMID: 27155294 DOI: 10.1016/j.tpb.2016.04.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 04/12/2016] [Accepted: 04/18/2016] [Indexed: 10/21/2022]
Abstract
Respiratory syncytial virus (RSV) is the main cause of lower respiratory tract infections in children. Whilst highly seasonal, RSV dynamics can have either one-year (annual) or two-year (biennial) cycles. Furthermore, some countries show a 'delayed biennial' pattern, where the epidemic peak in low incidence years is delayed. We develop a compartmental model for RSV infection, driven by a seasonal forcing function, and conduct parameter space and bifurcation analyses to document parameter ranges that give rise to these different seasonal patterns. The model is sensitive to the birth rate, transmission rate, and seasonality parameters, and can replicate RSV dynamics observed in different countries. The seasonality parameter must exceed a threshold for the model to produce biennial cycles. Intermediate values of the birth rate produce the greatest delay in these biennial cycles, while the model reverts to annual cycles if the duration of immunity is too short. Finally, the existence of period doubling and period halving bifurcations suggests robust model dynamics, in agreement with the known regularity of RSV outbreaks. These findings help explain observed RSV data, such as regular biennial dynamics in Western Australia, and delayed biennial dynamics in Finland. From a public health perspective, our findings provide insight into the drivers of RSV transmission, and a foundation for exploring RSV interventions.
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Affiliation(s)
- Alexandra B Hogan
- National Centre for Epidemiology and Population Health, Building 62, Corner Mills and Eggleston Roads, The Australian National University, Canberra ACT 2601, Australia.
| | - Kathryn Glass
- National Centre for Epidemiology and Population Health, Building 62, Corner Mills and Eggleston Roads, The Australian National University, Canberra ACT 2601, Australia
| | - Hannah C Moore
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, Western Australia, Australia
| | - Robert S Anderssen
- CSIRO Data61; Mathematical Sciences Institute, The Australian National University; Mathematics and Statistics, La Trobe University, Australia
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86
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Clinical Presentation and Birth Outcomes Associated with Respiratory Syncytial Virus Infection in Pregnancy. PLoS One 2016; 11:e0152015. [PMID: 27031702 PMCID: PMC4816499 DOI: 10.1371/journal.pone.0152015] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 03/08/2016] [Indexed: 11/30/2022] Open
Abstract
Background Respiratory syncytial virus (RSV) is the most important cause of viral pneumonia in children worldwide. A maternal vaccine may protect both the mother and infant from RSV illness. The epidemiology and clinical presentation of RSV in pregnant and postpartum women is not well-described. Methods Data were collected from a prospective, randomized trial of influenza immunization in pregnant women in rural southern Nepal. Women were enrolled in their second trimester of pregnancy and followed until six months postpartum. Active weekly home-based surveillance for febrile respiratory illness was performed. Mid-nasal swabs collected with episodes of respiratory illness were tested for RSV by real-time polymerase chain reaction. Results RSV was detected in 14 (0.4%) illness episodes in 3693 women over 3554 person-years of surveillance from 2011–2014. RSV incidence was 3.9/1000 person-years overall, and 11.8/1000 person-years between September and December. Seven (50%) women sought care for RSV illness; none died. Of the 7 (50%) illness episodes during pregnancy, all had live births with 2 (29%) preterm births and a median birthweight of 3060 grams. This compares to 469 (13%) preterm births and a median birthweight of 2790 grams in women without RSV during pregnancy. Of the 7 mothers with postpartum RSV infection, RSV was detected in 4 (57%) of their infants. Conclusions RSV was an uncommon cause of febrile respiratory illness in mothers during pregnancy in Nepal. These data will inform prevention and therapeutic strategies against RSV in resource-limited settings.
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87
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Ruckwardt TJ, Morabito KM, Graham BS. Determinants of early life immune responses to RSV infection. Curr Opin Virol 2016; 16:151-157. [PMID: 26986236 DOI: 10.1016/j.coviro.2016.01.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 01/07/2016] [Indexed: 12/17/2022]
Abstract
Respiratory syncytial virus causes significant morbidity and mortality in both developed and developing countries, and a vaccine that adequately protects from severe disease remains an important unmet need. RSV disease has an inordinate impact on the very young, and the physical and immunological immaturity of early life complicates vaccine design. Defining and targeting the functional capacities of early life immune responses and controlling responses during primary antigen exposure with selected vaccine delivery approaches will be important for protecting infants by active immunization. Alternatively, vaccination of older children and pregnant mothers may ameliorate disease burden indirectly until infants reach about six months of age, when they can generate more effective anti-RSV immune responses.
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Affiliation(s)
- Tracy J Ruckwardt
- Vaccine Research Center, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, MD, USA.
| | - Kaitlyn M Morabito
- Vaccine Research Center, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, MD, USA
| | - Barney S Graham
- Vaccine Research Center, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, MD, USA
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88
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Russell CJ, Hurwitz JL. Sendai virus as a backbone for vaccines against RSV and other human paramyxoviruses. Expert Rev Vaccines 2015; 15:189-200. [PMID: 26648515 DOI: 10.1586/14760584.2016.1114418] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Human paramyxoviruses are the etiological agents for life-threatening respiratory virus infections of infants and young children. These viruses, including respiratory syncytial virus (RSV), the human parainfluenza viruses (hPIV1-4) and human metapneumovirus (hMPV), are responsible for millions of serious lower respiratory tract infections each year worldwide. There are currently no standard treatments and no licensed vaccines for any of these pathogens. Here we review research with which Sendai virus, a mouse parainfluenza virus type 1, is being advanced as a Jennerian vaccine for hPIV1 and as a backbone for RSV, hMPV and other hPIV vaccines for children.
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Affiliation(s)
- Charles J Russell
- a Department of Infectious Diseases , St. Jude Children's Research Hospital , Memphis , TN , USA.,b Department of Microbiology, Immunology and Biochemistry , University of Tennessee Health Science Center , Memphis , TN , USA
| | - Julia L Hurwitz
- a Department of Infectious Diseases , St. Jude Children's Research Hospital , Memphis , TN , USA.,b Department of Microbiology, Immunology and Biochemistry , University of Tennessee Health Science Center , Memphis , TN , USA
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89
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Abstract
Respiratory syncytial virus (RSV) infection is the most important cause of hospitalization in infants and is one of the leading global causes of infant mortality and as such its prevention through vaccination is a public health priority. While essential for the successful implementation of vaccine programs, there remains a paucity of data on the epidemiology of the virus in different settings and age groups and limited knowledge about virus transmission and the health-care costs of the disease. Such data are now needed to populate health economic models and to inform optimal approaches to disease control through vaccination.
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Affiliation(s)
- Simon B Drysdale
- a Oxford Vaccine Group, Department of Paediatrics , University of Oxford , Oxford , UK.,b NIHR Oxford Biomedical Research Centre, Level 2 , Children's Hospital , Oxford , UK
| | - Charles J Sande
- a Oxford Vaccine Group, Department of Paediatrics , University of Oxford , Oxford , UK
| | - Christopher A Green
- a Oxford Vaccine Group, Department of Paediatrics , University of Oxford , Oxford , UK
| | - Andrew J Pollard
- a Oxford Vaccine Group, Department of Paediatrics , University of Oxford , Oxford , UK.,b NIHR Oxford Biomedical Research Centre, Level 2 , Children's Hospital , Oxford , UK
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Adherence to Palivizumab for Respiratory Syncytial Virus Prevention in the Canadian Registry of Palivizumab. Pediatr Infect Dis J 2015; 34:e290-7. [PMID: 26780032 DOI: 10.1097/inf.0000000000000922] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infections in infants. Palivizumab, a means of passive prophylaxis, relies on patient adherence to ensure therapeutic effectiveness. The objective of this study is to evaluate the association between adherence and the incidence of RSV-associated outcomes and to identify demographic factors that may impact adherence. METHODS Infants were recruited into the Canadian registry of palivizumab (CARESS) with parental consent. Monthly interviews collected information on palivizumab administration and RSV-associated outcomes. An infant was considered adherent if they received all of their expected injections or ≥5 injections within the appropriate interdose intervals. RESULTS Nineteen thousand two hundred thirty-five infants received a total of 83,447 injections from October 2005 to May 2014. Adherence was more likely in infants with higher maternal education and in those with siblings. Adherence was less likely in infants of aboriginal descent, with mothers who smoke and older infants. Adherence was significantly associated [odds ratio (95% confidence interval), P value] with a lower incidence of RSV infection [0.74 (0.60-0.93), 0.01] but not with RSV-associated hospitalization. However, in those hospitalized for RSV, adherence was significantly associated with the incidence of intubation and duration of hospitalization, intensive care stay and respiratory support. CONCLUSIONS Adherence may have implications in children with less severe RSV infections and those who are already hospitalized for a RSV infection. Our study also identifies subpopulations that are more likely to be nonadherent to palivizumab therapy. Future studies should aim to validate the relationship among adherence, palivizumab levels and RSV-associated outcomes.
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91
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Noah TL, Auten R, Schwarze J, Davis S. Pediatric pulmonology year in review 2014: Part 2. Pediatr Pulmonol 2015; 50:1140-6. [PMID: 26193432 DOI: 10.1002/ppul.23252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2015] [Revised: 06/22/2015] [Accepted: 06/24/2015] [Indexed: 11/07/2022]
Abstract
To better meet the needs of our readership for updated perspectives on the rapidly expanding knowledge in our field, we here summarize the past year's publications in our major topic areas, as well as selected publications in these areas from the core clinical journal literature outside our own pages. This is Part 2 of a series and covers articles on neonatal lung disease, pulmonary physiology, and respiratory infection.
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Affiliation(s)
- Terry L Noah
- Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Richard Auten
- Department of Pediatrics, Duke University, Durham, North Carolina
| | - Jurgen Schwarze
- Department of Child Life and Health, The University of Edinburgh, Edinburgh, UK
| | - Stephanie Davis
- Department of Pediatrics, Riley Children's Hospital, Indiana University School of Medicine, Indianapolis, Indiana
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Lower respiratory tract infection caused by respiratory syncytial virus: current management and new therapeutics. THE LANCET RESPIRATORY MEDICINE 2015; 3:888-900. [PMID: 26411809 DOI: 10.1016/s2213-2600(15)00255-6] [Citation(s) in RCA: 215] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 06/15/2015] [Accepted: 06/22/2015] [Indexed: 01/20/2023]
Abstract
Respiratory syncytial virus (RSV) is a major worldwide cause of morbidity and mortality in children under five years of age. Evidence-based management guidelines suggest that there is no effective treatment for RSV lower respiratory tract infection (LRTI) and that supportive care, ie, hydration and oxygenation, remains the cornerstone of clinical management. However, RSV treatments in development in the past decade include 10 vaccines and 11 therapeutic agents in active clinical trials. Maternal vaccination is particularly relevant because the most severe disease occurs within the first 6 months of life, when children are unlikely to benefit from active immunisation. We must optimise the implementation of novel RSV therapeutics by understanding the target populations, showing safety, and striving for acceptable pricing in the context of this worldwide health problem. In this Review, we outline the limitations of RSV LRTI management, the drugs in development, and the remaining challenges related to study design, regulatory approval, and implementation.
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Kinyanjui TM, House TA, Kiti MC, Cane PA, Nokes DJ, Medley GF. Vaccine Induced Herd Immunity for Control of Respiratory Syncytial Virus Disease in a Low-Income Country Setting. PLoS One 2015; 10:e0138018. [PMID: 26390032 PMCID: PMC4577090 DOI: 10.1371/journal.pone.0138018] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 08/24/2015] [Indexed: 11/23/2022] Open
Abstract
Background Respiratory syncytial virus (RSV) is globally ubiquitous, and infection during the first six months of life is a major risk for severe disease and hospital admission; consequently RSV is the most important viral cause of respiratory morbidity and mortality in young children. Development of vaccines for young infants is complicated by the presence of maternal antibodies and immunological immaturity, but vaccines targeted at older children avoid these problems. Vaccine development for young infants has been unsuccessful, but this is not the case for older children (> 6m). Would vaccinating older children have a significant public health impact? We developed a mathematical model to explore the benefits of a vaccine against RSV. Methods and Findings We have used a deterministic age structured model capturing the key epidemiological characteristics of RSV and performed a statistical maximum-likelihood fit to age-specific hospitalization data from a developing country setting. To explore the effects of vaccination under different mixing assumptions, we included two versions of contact matrices: one from a social contact diary study, and the second a synthesised construction based on demographic data. Vaccination is assumed to elicit an immune response equivalent to primary infection. Our results show that immunisation of young children (5–10m) is likely to be a highly effective method of protection of infants (<6m) against hospitalisation. The majority benefit is derived from indirect protection (herd immunity). A full sensitivity and uncertainty analysis using Latin Hypercube Sampling of the parameter space shows that our results are robust to model structure and model parameters. Conclusions This result suggests that vaccinating older infants and children against RSV can have a major public health benefit.
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Affiliation(s)
- Timothy M. Kinyanjui
- School of Mathematics, University of Manchester, Manchester, M13 9PL, United Kingdom
- * E-mail:
| | - Thomas A. House
- School of Mathematics, University of Manchester, Manchester, M13 9PL, United Kingdom
- Department of Mathematics and WIDER, University of Warwick, Coventry, CV4 7AL, United Kingdom
| | - Moses C. Kiti
- Kenya Medical Research Institute (KEMRI) – Wellcome Trust Research Programme, KEMRI Centre for Geographic Medicine Research – Coast, Kilifi, Kenya
| | | | - David J. Nokes
- Kenya Medical Research Institute (KEMRI) – Wellcome Trust Research Programme, KEMRI Centre for Geographic Medicine Research – Coast, Kilifi, Kenya
- School of Life Sciences and WIDER, University of Warwick, Coventry, CV4 7AL, United Kingdom
| | - Graham F. Medley
- Department of Global Health and Development, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, United Kingdom
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94
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Polack FP. The changing landscape of respiratory syncytial virus. Vaccine 2015; 33:6473-8. [PMID: 26247900 DOI: 10.1016/j.vaccine.2015.06.119] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 06/22/2015] [Accepted: 06/23/2015] [Indexed: 01/05/2023]
Abstract
Recognition of the acute and chronic burden of respiratory syncytial virus (RSV) lower respiratory tract infections (LRTI) sparked a wave of initiatives to develop preventive and therapeutic products against the pathogen in recent years. RSV is a leading cause of hospitalization in infants in industrialized and developing countries, has been causally linked to recurrent wheezing during childhood, associated with pediatric asthma, and is an important cause of mortality in the first months of life in the developing world. Significant changes in the epidemiology, clinical manifestations, and severe consequences of LRTI may emerge in the next decade with the advent of novel preventive strategies against RSV. This manuscript outlines some of these changes and discusses potential scenarios based on the current literature and experiences with other pathogens.
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Affiliation(s)
- Fernando P Polack
- Vanderbilt Vaccine Center at Vanderbilt University, Nashville, TN, United States; Fundacion INFANT, Buenos Aires, Argentina.
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95
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Wu A, Budge PJ, Williams J, Griffin MR, Edwards KM, Johnson M, Zhu Y, Hartinger S, Verastegui H, Gil AI, Lanata CF, Grijalva CG. Incidence and Risk Factors for Respiratory Syncytial Virus and Human Metapneumovirus Infections among Children in the Remote Highlands of Peru. PLoS One 2015; 10:e0130233. [PMID: 26107630 PMCID: PMC4479592 DOI: 10.1371/journal.pone.0130233] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2015] [Accepted: 05/17/2015] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION The disease burden and risk factors for respiratory syncytial virus (RSV) and human metapneumovirus (MPV) infections among children living in remote, rural areas remain unclear. MATERIALS AND METHODS We conducted a prospective, household-based cohort study of children aged <3 years living in remote rural highland communities in San Marcos, Cajamarca, Peru. Acute respiratory illnesses (ARI), including lower respiratory tract infection (LRTI), were monitored through weekly household visits from March 2009 through September 2011. Nasal swabs collected during ARI/LRTI were tested for RSV, MPV, and other respiratory viruses using real-time RT-PCR. Incidence rates and rate ratios were calculated using mixed effects Poisson regression. RESULTS Among 892 enrolled children, incidence rates of RSV and MPV ARI were 30 and 17 episodes per 100 child-years, respectively. The proportions of RSV and MPV ARI that presented as LRTI were 12.5% and 8.9%, respectively. Clinic visits for ARI and hospitalizations were significantly more frequent (all p values <0.05) among children with RSV (clinic 41% and hospital 5.3%) and MPV ARI (38% and 3.5%) when compared with other viral infections (23% and 0.7%) and infections without virus detected (24% and 0.6%). In multivariable analysis, risk factors for RSV detection included younger age (RR 1.02, 95% CI: 1.00-1.03), the presence of a smoker in the house (RR 1.63, 95% CI: 1.12-2.38), residing at higher altitudes (RR 1.93, 95% CI: 1.25-3.00 for 2nd compared to 1st quartile residents; RR 1.98, 95% CI: 1.26-3.13 for 3rd compared to 1st quartile residents). Having an unemployed household head was significantly associated with MPV risk (RR 2.11, 95% CI: 1.12-4.01). CONCLUSION In rural high altitude communities in Peru, childhood ARI due to RSV or MPV were common and associated with higher morbidity than ARI due to other viruses or with no viral detections. The risk factors identified in this study may be considered for interventional studies to control infections by these viruses among young children from developing countries.
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Affiliation(s)
- Andrew Wu
- School of Medicine, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Philip J. Budge
- Division of Infectious Diseases, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - John Williams
- Department of Pediatrics, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Marie R. Griffin
- Department of Health Policy, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Kathryn M. Edwards
- Department of Pediatrics, Vanderbilt University, Nashville, Tennessee, United States of America
- Vanderbilt Vaccine Research Program, Division of Infectious Diseases, Department of Pediatrics, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Monika Johnson
- Department of Pediatrics, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Yuwei Zhu
- Department of Biostatistics, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Stella Hartinger
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- Instituto de Investigación Nutricional, Lima, Peru
| | | | - Ana I. Gil
- Instituto de Investigación Nutricional, Lima, Peru
| | | | - Carlos G. Grijalva
- Department of Health Policy, Vanderbilt University, Nashville, Tennessee, United States of America
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Modjarrad K, Giersing B, Kaslow DC, Smith PG, Moorthy VS. WHO consultation on Respiratory Syncytial Virus Vaccine Development Report from a World Health Organization Meeting held on 23-24 March 2015. Vaccine 2015; 34:190-197. [PMID: 26100926 PMCID: PMC6858870 DOI: 10.1016/j.vaccine.2015.05.093] [Citation(s) in RCA: 151] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 05/29/2015] [Indexed: 01/06/2023]
Abstract
Respiratory syncytial virus (RSV) is a globally prevalent cause of lower respiratory infection in neonates and infants. Despite its disease burden, a safe and effective RSV vaccine has remained elusive. In recent years, improved understanding of RSV biology and innovations in immunogen design has resulted in the advancement of multiple vaccine candidates into the clinical development pipeline. Given the growing number of vaccines in clinical trials, the rapid pace at which they are being tested, and the likelihood that an RSV vaccine will reach the commercial market in the next 5–10 years, consensus and guidance on clinical development pathways and licensure routes are needed now, before large-scale efficacy trials commence. In pursuit of this aim, the World Health Organization convened the first RSV vaccine consultation in 15 years on the 23rd and 24th of March, 2015 in Geneva, Switzerland. The meeting’s primary objective was to provide guidance on clinical endpoints and development pathways for vaccine trials with a focus on considerations of low- and middle-income countries. Meeting participants reached consensus on candidate case definitions for RSV disease, considerations for clinical efficacy endpoints, and the clinical development pathway for active and passive immunization trials in maternal and pediatric populations. The strategic focus of this meeting was on the development of high quality, safe and efficacious RSV preventive interventions for global use and included: (1) maternal/passive immunization to prevent RSV disease in infants less than 6 months; (2) pediatric immunization to prevent RSV disease in infants and young children once protection afforded by maternal immunization wanes.
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Affiliation(s)
- Kayvon Modjarrad
- Initiative for Vaccine Research, World Health Organization, CH-1211 Geneva 27, Switzerland; U.S Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA
| | - Birgitte Giersing
- Initiative for Vaccine Research, World Health Organization, CH-1211 Geneva 27, Switzerland
| | | | - Peter G Smith
- London School of Hygiene and Tropical Medicine, London WC1E7HT, UK
| | - Vasee S Moorthy
- Initiative for Vaccine Research, World Health Organization, CH-1211 Geneva 27, Switzerland.
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Munywoki PK, Koech DC, Agoti CN, Bett A, Cane PA, Medley GF, Nokes DJ. Frequent Asymptomatic Respiratory Syncytial Virus Infections During an Epidemic in a Rural Kenyan Household Cohort. J Infect Dis 2015; 212:1711-8. [PMID: 25941331 PMCID: PMC4633757 DOI: 10.1093/infdis/jiv263] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 04/24/2015] [Indexed: 11/24/2022] Open
Abstract
Background. The characteristics, determinants, and potential contribution to transmission of asymptomatic cases of respiratory syncytial virus (RSV) infection have not been well described. Methods. A cohort of 47 households (493 individuals) in coastal Kenya was recruited and followed for a 26-week period spanning a complete RSV season. Nasopharyngeal swab specimens were requested weekly, during the first 4 weeks, and twice weekly thereafter from all household members, regardless of illness status. The samples were screened for a range of respiratory viruses by multiplex real-time polymerase chain reaction. Results. Tests on 16 928 samples yielded 205 RSV infection episodes in 179 individuals (37.1%) from 40 different households. Eighty-six episodes (42.0%) were asymptomatic. Factors independently associated with an increased risk of asymptomatic RSV infection episodes were higher age, shorter duration of infection, bigger household size, lower peak viral load, absence of concurrent RSV infections within the household, infection by RSV group B, and no prior human rhinovirus infections. The propensity of RSV spread in households was dependent on symptom status and amount (duration and load) of virus shed. Conclusions. While asymptomatic RSV was less likely to spread, the high frequency of symptomless RSV infection episodes highlights a potentially important role of asymptomatic infections in the community transmission of RSV.
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Affiliation(s)
- Patrick K Munywoki
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
| | - Dorothy C Koech
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
| | - Charles N Agoti
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
| | - Ann Bett
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
| | - Patricia A Cane
- High Containment Microbiology, Public Health England, Salisbury
| | - Graham F Medley
- London School of Hygiene and Tropical Medicine (WIDER) Centre, University of Warwick, Coventry, United Kingdom
| | - D James Nokes
- Epidemiology and Demography Department, KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya School of Life Sciences (WIDER) Centre, University of Warwick, Coventry, United Kingdom Warwick Infectious Disease Epidemiology Research (WIDER) Centre, University of Warwick, Coventry, United Kingdom
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98
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Velasco-Hernández JX, Núñez-López M, Comas-García A, Cherpitel DEN, Ocampo MC. Superinfection between influenza and RSV alternating patterns in San Luis Potosí State, México. PLoS One 2015; 10:e0115674. [PMID: 25803450 PMCID: PMC4372574 DOI: 10.1371/journal.pone.0115674] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 11/26/2014] [Indexed: 11/19/2022] Open
Abstract
The objective of this paper is to explain through the ecological hypothesis superinfection and competitive interaction between two viral populations and niche (host) availability, the alternating patterns of Respiratory Syncytial Virus (RSV) and influenza observed in a regional hospital in San Luis Potosí State, México using a mathematical model as a methodological tool. The data analyzed consists of community-based and hospital-based Acute Respiratory Infections (ARI) consultations provided by health-care institutions reported to the State Health Service Epidemiology Department from 2003 through 2009.
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Affiliation(s)
| | - Mayra Núñez-López
- Departamento de Matemáticas Aplicadas y Sistemas, DMAS, Universidad Autónoma Metropolitana, Cuajimalpa, Av. Vasco de Quiroga 4871, Col. Santa Fe Cuajimalpa, Cuajimalpa de Morelos, 05300, México, D.F., México
- * E-mail:
| | - Andreu Comas-García
- Facultad de Medicina, Universidad Nacional Autónoma de México, México, Av. Universidad 3000, CP 04510, Mexico City, Mexico
| | - Daniel Ernesto Noyola Cherpitel
- Departamento de Microbiología, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, Av. Venustiano Carranza 2405, CP 78210, San Luis Potosí, México
| | - Marcos Capistrán Ocampo
- Centro de Investigación en Matemáticas A.C., Jalisco S/N, Col. Valenciana, 36240, Guanajuato, Gto., México
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Poletti P, Merler S, Ajelli M, Manfredi P, Munywoki PK, Nokes D, Melegaro A. Evaluating vaccination strategies for reducing infant respiratory syncytial virus infection in low-income settings. BMC Med 2015; 13:49. [PMID: 25857701 PMCID: PMC4372170 DOI: 10.1186/s12916-015-0283-x] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 01/22/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract disease and related hospitalization of young children in least developed countries. Individuals are repeatedly infected, but it is the first exposure, often in early infancy, that results in the vast majority of severe RSV disease. Unfortunately, due to immunological immaturity, infants are a problematic RSV vaccine target. Several trials are ongoing to identify a suitable candidate vaccine and target group, but no immunization program is yet in place. METHODS In this work, an individual-based model that explicitly accounts for the socio-demographic population structure is developed to investigate RSV transmission patterns in a rural setting of Kenya and to evaluate the potential effectiveness of alternative population targets in reducing RSV infant infection. RESULTS We find that household transmission is responsible for 39% of infant infections and that school-age children are the main source of infection within the household, causing around 55% of cases. Moreover, assuming a vaccine-induced protection equivalent to that of natural infection, our results show that annual vaccination of students is the only alternative strategy to routine immunization of infants able to trigger a relevant and persistent reduction of infant infection (on average, of 35.6% versus 41.5% in 10 years of vaccination). Interestingly, if vaccination of pregnant women boosts maternal antibody protection in infants by an additional 4 months, RSV infant infection will be reduced by 31.5%. CONCLUSIONS These preliminary evaluations support the efforts to develop vaccines and related strategies that go beyond targeting vaccines to those at highest risk of severe disease.
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Heikkinen T, Valkonen H, Waris M, Ruuskanen O. Transmission of respiratory syncytial virus infection within families. Open Forum Infect Dis 2015; 2:ofu118. [PMID: 25884006 PMCID: PMC4396434 DOI: 10.1093/ofid/ofu118] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 12/10/2014] [Indexed: 11/14/2022] Open
Abstract
Half of all family members of children hospitalized with RSV infection were positive for RSV around the time of the child's admission. In most cases, the likely source of the infant's RSV infection was an older sibling or a parent. Background. Because the production of an effective respiratory syncytial virus (RSV) vaccine for infants is challenging, vaccination of other family members is one viable alternative to prevent severe RSV illnesses in infants. Methods. In a prospective study, we enrolled all family members of children who were hospitalized with RSV infection. Nasal swabs for RSV detection were obtained from all participating family members. Data on respiratory symptoms in the family members prior to and after the child's admission were collected using standardized questionnaires. Results. At the time of or within 1 week after the index child's hospitalization, RSV was detected in 40 (77%) of the 52 families and in 60 (47%) of 129 family members. Forty-nine (82%) of RSV detections in the family members were associated with respiratory symptoms. A sibling or a parent was the probable primary case of RSV in 30 (58%) families. Respiratory syncytial virus loads in the nasal swabs were significantly higher (107.7) in index children than in their parents (105.1, P < .0001). Conclusions. In most cases, the likely source of an infant's RSV infection is an older sibling or a parent. These findings support the strategy of reducing the burden of RSV in infants by vaccination of their family members.
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Affiliation(s)
- Terho Heikkinen
- Departments of Pediatrics ; Turku University Hospital , Finland
| | - Heikki Valkonen
- Departments of Pediatrics ; Turku University Hospital , Finland
| | | | - Olli Ruuskanen
- Departments of Pediatrics ; Turku University Hospital , Finland
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