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Kuylen E, Willem L, Broeckhove J, Beutels P, Hens N. Clustering of susceptible individuals within households can drive measles outbreaks: an individual-based model exploration. Sci Rep 2020; 10:19645. [PMID: 33184409 PMCID: PMC7665185 DOI: 10.1038/s41598-020-76746-3] [Citation(s) in RCA: 8] [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: 12/10/2019] [Accepted: 10/19/2020] [Indexed: 01/18/2023] Open
Abstract
When estimating important measures such as the herd immunity threshold, and the corresponding efforts required to eliminate measles, it is often assumed that susceptible individuals are uniformly distributed throughout populations. However, unvaccinated individuals may be clustered in a variety of ways, including by geographic location, by age, in schools, or in households. Here, we investigate to which extent different levels of within-household clustering of susceptible individuals may impact the risk and persistence of measles outbreaks. To this end, we apply an individual-based model, Stride, to a population of 600,000 individuals, using data from Flanders, Belgium. We construct a metric to estimate the level of within-household susceptibility clustering in the population. Furthermore, we compare realistic scenarios regarding the distribution of susceptible individuals within households in terms of their impact on epidemiological measures for outbreak risk and persistence. We find that higher levels of within-household clustering of susceptible individuals increase the risk, size and persistence of measles outbreaks. Ignoring within-household clustering thus leads to underestimations of required measles elimination and outbreak mitigation efforts.
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Affiliation(s)
- Elise Kuylen
- Centre for Health Economics Research and Modelling Infectious Diseases (CHERMID), Vaccine and Infectious Disease Institute, University of Antwerp, Antwerp, Belgium.
- Data Science Institute (DSI), Hasselt University, Hasselt, Belgium.
| | - Lander Willem
- Centre for Health Economics Research and Modelling Infectious Diseases (CHERMID), Vaccine and Infectious Disease Institute, University of Antwerp, Antwerp, Belgium
| | - Jan Broeckhove
- IDLab, Department of Mathematics and Computer Science, University of Antwerp, Antwerp, Belgium
| | - Philippe Beutels
- Centre for Health Economics Research and Modelling Infectious Diseases (CHERMID), Vaccine and Infectious Disease Institute, University of Antwerp, Antwerp, Belgium
| | - Niel Hens
- Centre for Health Economics Research and Modelling Infectious Diseases (CHERMID), Vaccine and Infectious Disease Institute, University of Antwerp, Antwerp, Belgium
- Data Science Institute (DSI), Hasselt University, Hasselt, Belgium
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Kohlmaier B, Schweintzger NA, Zenz W. Measles recognition during measles outbreak at a paediatric university hospital, Austria, January to February 2017. ACTA ACUST UNITED AC 2020; 25. [PMID: 31992389 PMCID: PMC6988273 DOI: 10.2807/1560-7917.es.2020.25.3.1900260] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Recognition of measles is crucial to prevent transmissions in the hospital settings. Little is known about the level of recognition of measles and possible causes of not recognising the disease by physicians in the post-vaccine era. We report on a measles outbreak in a paediatric hospital in Austria in January to February 2017 with strikingly high numbers of not recognised cases. The extent and course of the outbreak were assessed via retrospective case finding. Thirteen confirmed measles cases were identified, two with atypical clinical picture. Of eight cases with no known epidemiological link, only one was diagnosed immediately; four were recognised with delay and three only retrospectively. Eleven typical measles cases had four ‘unrecognised visits’ to the outpatient clinic and 28 on the ward. Two atypical cases had two ‘unrecognised visits’ to the outpatient clinic and 19 on the ward. Thirteen clinicians did not recognise typical measles (atypical cases not included). Twelve of 23 physicians involved had never encountered a patient with measles before. The direct and indirect costs related to the outbreak were calculated to be over EUR 80,000. Our findings suggest the need to establish regular training programmes about measles, including diagnostic pitfalls in paediatric hospitals.
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Affiliation(s)
- Benno Kohlmaier
- Department of General Paediatrics, Medical University of Graz, Graz, Austria
| | - Nina A Schweintzger
- Department of General Paediatrics, Medical University of Graz, Graz, Austria
| | - Werner Zenz
- Department of General Paediatrics, Medical University of Graz, Graz, Austria
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Fournet N, Mollema L, Ruijs WL, Harmsen IA, Keck F, Durand JY, Cunha MP, Wamsiedel M, Reis R, French J, Smit EG, Kitching A, van Steenbergen JE. Under-vaccinated groups in Europe and their beliefs, attitudes and reasons for non-vaccination; two systematic reviews. BMC Public Health 2018; 18:196. [PMID: 29378545 PMCID: PMC5789742 DOI: 10.1186/s12889-018-5103-8] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 01/19/2018] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Despite effective national immunisation programmes in Europe, some groups remain incompletely or un-vaccinated ('under-vaccinated'), with underserved minorities and certain religious/ideological groups repeatedly being involved in outbreaks of vaccine preventable diseases (VPD). Gaining insight into factors regarding acceptance of vaccination of 'under-vaccinated groups' (UVGs) might give opportunities to communicate with them in a trusty and reliable manner that respects their belief system and that, maybe, increase vaccination uptake. We aimed to identify and describe UVGs in Europe and to describe beliefs, attitudes and reasons for non-vaccination in the identified UVGs. METHODS We defined a UVG as a group of persons who share the same beliefs and/or live in socially close-knit communities in Europe and who have/had historically low vaccination coverage and/or experienced outbreaks of VPDs since 1950. We searched MEDLINE, EMBASE and PsycINFO databases using specific search term combinations. For the first systematic review, studies that described a group in Europe with an outbreak or low vaccination coverage for a VPD were selected and for the second systematic review, studies that described possible factors that are associated with non-vaccination in these groups were selected. RESULTS We selected 48 articles out of 606 and 13 articles out of 406 from the first and second search, respectively. Five UVGs were identified in the literature: Orthodox Protestant communities, Anthroposophists, Roma, Irish Travellers, and Orthodox Jewish communities. The main reported factors regarding vaccination were perceived non-severity of traditional "childhood" diseases, fear of vaccine side-effects, and need for more information about for example risk of vaccination. CONCLUSIONS Within each UVG identified, there are a variety of health beliefs and objections to vaccination. In addition, similar factors are shared by several of these groups. Communication strategies regarding these similar factors such as educating people about the risks associated with being vaccinated versus not being vaccinated, addressing their concerns, and countering vaccination myths present among members of a specific UVG through a trusted source, can establish a reliable relationship with these groups and increase their vaccination uptake. Furthermore, other interventions such as improving access to health care could certainly increase vaccination uptake in Roma and Irish travellers.
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Affiliation(s)
- N. Fournet
- Centre for Infectious Diseases Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - L. Mollema
- Centre for Infectious Diseases Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
- National Institute for Public Health and the Environment, Epidemiology and Surveillance Unit, P.O. Box 1 (internal P.O. Box 75), 3720 BA Bilthoven, the Netherlands
| | - W. L. Ruijs
- Centre for Infectious Diseases Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - I. A. Harmsen
- Municipal Health Service (GGD) Amsterdam, Amsterdam, The Netherlands
| | - F. Keck
- Laboratoire d’anthropologie sociale - Centre National de la Recherche Scientifique, Paris, France
| | - J. Y. Durand
- Centre for Research in Anthropology, Universidade do Minho (CRIA - UMinho), Braga, Portugal
| | - M. P. Cunha
- Centre for Research in Anthropology, Universidade do Minho (CRIA - UMinho), Braga, Portugal
| | - M. Wamsiedel
- Department of Public Health at Xi’an Jiaotong-Liverpool University, Suzhou, China
| | - R. Reis
- Leiden University Medical Centre, Leiden, The Netherlands
- Amsterdam Institute for Social Science Research, University of Amsterdam, Amsterdam, The Netherlands
- The Children’s Institute, University of Cape Town, Cape Town, South Africa
| | - J. French
- Strategic Social Marketing, Liphook, UK
- Brighton University Business School, Brighton, UK
| | - E. G. Smit
- Amsterdam School of Communication Research, University of Amsterdam, Amsterdam, The Netherlands
| | - A. Kitching
- Department of Public Health, Health Service Executive, St Finbarr’s Hospital, Cork, Republic of Ireland
| | - J. E. van Steenbergen
- Centre for Infectious Diseases Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
- Centre for Infectious Diseases, Leiden University Medical Centre, Leiden, The Netherlands
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Polio and Measles Down the Drain: Environmental Enterovirus Surveillance in the Netherlands, 2005 to 2015. Appl Environ Microbiol 2017; 83:AEM.00558-17. [PMID: 28432101 DOI: 10.1128/aem.00558-17] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 04/16/2017] [Indexed: 11/20/2022] Open
Abstract
Polioviruses (PVs) are members of the genus Enterovirus In the Netherlands, the exclusion of PV circulation is based on clinical enterovirus (EV) surveillance (CEVS) of EV-positive cases and routine environmental EV surveillance (EEVS) conducted on sewage samples collected in the region of the Netherlands where vaccination coverage is low due to religious reasons. We compared the EEVS data to those of the CEVS to gain insight into the relevance of EEVS for poliovirus and nonpolio enterovirus surveillance. Following the polio outbreak in Syria, EEVS was performed at the primary refugee center in Ter Apel in the Netherlands, and data were compared to those of CEVS and EEVS. Furthermore, we assessed the feasibility of poliovirus detection by EEVS using measles virus detection in sewage during a measles outbreak as a proxy. Two Sabin-like PVs were found in routine EEVS, 11 Sabin-like PVs were detected in the CEVS, and one Sabin-like PV was found in the Ter Apel sewage. We observed significant differences between the three programs regarding which EVs were found. In 6 sewage samples collected during the measles outbreak in 2013, measles virus RNA was detected in regions where measles cases were identified. In conclusion, we detected PVs, nonpolio EVs, and measles virus in sewage and showed that environmental surveillance is useful for poliovirus detection in the Netherlands, where live oral poliovirus vaccine is not used and communities with lower vaccination coverage exist. EEVS led to the detection of EV types not seen in the CEVS, showing that EEVS is complementary to CEVS.IMPORTANCE We show that environmental enterovirus surveillance complements clinical enterovirus surveillance for poliovirus detection, or exclusion, and for nonpolio enterovirus surveillance. Even in the presence of adequate surveillance, only a very limited number of Sabin-like poliovirus strains were detected in a 10-year period, and no signs of transmission of oral polio vaccine (OPV) strains were found in a country using exclusively inactivated polio vaccine (IPV). Measles viruses can be detected during an outbreak in sewage samples collected and concentrated following procedures used for environmental enterovirus surveillance.
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van Lier A, McDonald SA, Bouwknegt M, Kretzschmar ME, Havelaar AH, Mangen MJJ, Wallinga J, de Melker HE. Disease Burden of 32 Infectious Diseases in the Netherlands, 2007-2011. PLoS One 2016; 11:e0153106. [PMID: 27097024 PMCID: PMC4838234 DOI: 10.1371/journal.pone.0153106] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 03/23/2016] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Infectious disease burden estimates provided by a composite health measure give a balanced view of the true impact of a disease on a population, allowing the relative impact of diseases that differ in severity and mortality to be monitored over time. This article presents the first national disease burden estimates for a comprehensive set of 32 infectious diseases in the Netherlands. METHODS AND FINDINGS The average annual disease burden was computed for the period 2007-2011 for selected infectious diseases in the Netherlands using the disability-adjusted life years (DALY) measure. The pathogen- and incidence-based approach was adopted to quantify the burden due to both morbidity and premature mortality associated with all short and long-term consequences of infection. Natural history models, disease progression probabilities, disability weights, and other parameters were adapted from previous research. Annual incidence was obtained from statutory notification and other surveillance systems, which was corrected for under-ascertainment and under-reporting. The highest average annual disease burden was estimated for invasive pneumococcal disease (9444 DALYs/year; 95% uncertainty interval [UI]: 8911-9961) and influenza (8670 DALYs/year; 95% UI: 8468-8874), which represents 16% and 15% of the total burden of all 32 diseases, respectively. The remaining 30 diseases ranked by number of DALYs/year from high to low were: HIV infection, legionellosis, toxoplasmosis, chlamydia, campylobacteriosis, pertussis, tuberculosis, hepatitis C infection, Q fever, norovirus infection, salmonellosis, gonorrhoea, invasive meningococcal disease, hepatitis B infection, invasive Haemophilus influenzae infection, shigellosis, listeriosis, giardiasis, hepatitis A infection, infection with STEC O157, measles, cryptosporidiosis, syphilis, rabies, variant Creutzfeldt-Jakob disease, tetanus, mumps, rubella, diphtheria, and poliomyelitis. The very low burden for the latter five diseases can be attributed to the National Immunisation Programme. The average disease burden per individual varied from 0.2 (95% UI: 0.1-0.4) DALYs per 100 infections for giardiasis, to 5081 and 3581 (95% UI: 3540-3611) DALYs per 100 infections for rabies and variant Creutzfeldt-Jakob disease, respectively. CONCLUSIONS For guiding and supporting public health policy decisions regarding the prioritisation of interventions and preventive measures, estimates of disease burden and the comparison of burden between diseases can be informative. Although the collection of disease-specific parameters and estimation of incidence is a process subject to continuous improvement, the current study established a baseline for assessing the impact of future public health initiatives.
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Affiliation(s)
- Alies van Lier
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - Scott A. McDonald
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - Martijn Bouwknegt
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - EPI group
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - Mirjam E. Kretzschmar
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
- Julius Centre for Health Sciences and Primary Care, University Medical Centre Utrecht (UMCU), Utrecht, The Netherlands
| | - Arie H. Havelaar
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | - Marie-Josée J. Mangen
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
- Julius Centre for Health Sciences and Primary Care, University Medical Centre Utrecht (UMCU), Utrecht, The Netherlands
| | - Jacco Wallinga
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - Hester E. de Melker
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
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van der Maas NAT, Woudenberg T, Hahné SJM, de Melker HE. Tolerability of Early Measles-Mumps-Rubella Vaccination in Infants Aged 6-14 Months During a Measles Outbreak in The Netherlands in 2013-2014. J Infect Dis 2015; 213:1466-71. [PMID: 26690343 PMCID: PMC4813742 DOI: 10.1093/infdis/jiv756] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 12/14/2015] [Indexed: 12/12/2022] Open
Abstract
Background. In 2013–2014, a measles outbreak spread through the Netherlands. To protect young infants, measles-mumps-rubella (MMR) vaccination was offered to those aged 6–14 months in municipalities with routine first-dose MMR vaccine coverage of <90%. We assessed the tolerability of this early administration of MMR vaccine. Methods. After study entry (n = 1866), parents of eligible infants (n = 10 097) completed a questionnaire (n = 1304). For infants who received an early MMR vaccine dose (n = 962), we asked for information about adverse events (AEs) associated with the dose. AE frequencies were compared between infants aged 6–8, 9–11, and 12–14 months. Using multivariable logistic regression, we assessed the association between the risk of AEs and age at early MMR vaccination. Results. The response rate was 13%. Parents of 59 infants (6.1%) and 350 infants (36.4%) who received early MMR vaccination reported local and systemic AEs, respectively. Parents of infants vaccinated at 6–8 months of age reported systemic AEs less frequently (32%) than parents of children vaccinated at 9–11 months (45%) and 12–14 months (43%) of age (P = <.001). For local AEs, there were no differences (5%, 7%, and 10%, respectively; P = .08). Compared with vaccination at 6 months, all older infants except those aged 14 months showed an increased risk for any AE and for systemic AEs starting 5–12 days after vaccination. Conclusions. Early MMR vaccination is well tolerated, with the lowest AE frequencies found in infants aged 6–8 months. It is a safe intervention for protecting young infants against measles.
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Affiliation(s)
- Nicoline A T van der Maas
- Center for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands
| | - T Woudenberg
- Center for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands
| | - S J M Hahné
- Center for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands
| | - H E de Melker
- Center for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands
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Burgess C, Peace A, Everett R, Allegri B, Garman P. Computational modeling of interventions and protective thresholds to prevent disease transmission in deploying populations. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2014; 2014:785752. [PMID: 25009579 PMCID: PMC4070471 DOI: 10.1155/2014/785752] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 05/05/2014] [Accepted: 05/07/2014] [Indexed: 01/05/2023]
Abstract
Military personnel are deployed abroad for missions ranging from humanitarian relief efforts to combat actions; delay or interruption in these activities due to disease transmission can cause operational disruptions, significant economic loss, and stressed or exceeded military medical resources. Deployed troops function in environments favorable to the rapid and efficient transmission of many viruses particularly when levels of protection are suboptimal. When immunity among deployed military populations is low, the risk of vaccine-preventable disease outbreaks increases, impacting troop readiness and achievement of mission objectives. However, targeted vaccination and the optimization of preexisting immunity among deployed populations can decrease the threat of outbreaks among deployed troops. Here we describe methods for the computational modeling of disease transmission to explore how preexisting immunity compares with vaccination at the time of deployment as a means of preventing outbreaks and protecting troops and mission objectives during extended military deployment actions. These methods are illustrated with five modeling case studies for separate diseases common in many parts of the world, to show different approaches required in varying epidemiological settings.
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Affiliation(s)
| | | | | | | | - Patrick Garman
- Military Vaccine Agency (MILVAX), Defense Health Headquarters, Falls Church, VA 22042, USA
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Barclay VC, Smieszek T, He J, Cao G, Rainey JJ, Gao H, Uzicanin A, Salathé M. Positive network assortativity of influenza vaccination at a high school: implications for outbreak risk and herd immunity. PLoS One 2014; 9:e87042. [PMID: 24505274 PMCID: PMC3914803 DOI: 10.1371/journal.pone.0087042] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 12/17/2013] [Indexed: 11/18/2022] Open
Abstract
Schools are known to play a significant role in the spread of influenza. High vaccination coverage can reduce infectious disease spread within schools and the wider community through vaccine-induced immunity in vaccinated individuals and through the indirect effects afforded by herd immunity. In general, herd immunity is greatest when vaccination coverage is highest, but clusters of unvaccinated individuals can reduce herd immunity. Here, we empirically assess the extent of such clustering by measuring whether vaccinated individuals are randomly distributed or demonstrate positive assortativity across a United States high school contact network. Using computational models based on these empirical measurements, we further assess the impact of assortativity on influenza disease dynamics. We found that the contact network was positively assortative with respect to influenza vaccination: unvaccinated individuals tended to be in contact more often with other unvaccinated individuals than with vaccinated individuals, and these effects were most pronounced when we analyzed contact data collected over multiple days. Of note, unvaccinated males contributed substantially more than unvaccinated females towards the measured positive vaccination assortativity. Influenza simulation models using a positively assortative network resulted in larger average outbreak size, and outbreaks were more likely, compared to an otherwise identical network where vaccinated individuals were not clustered. These findings highlight the importance of understanding and addressing heterogeneities in seasonal influenza vaccine uptake for prevention of large, protracted school-based outbreaks of influenza, in addition to continued efforts to increase overall vaccine coverage.
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Affiliation(s)
- Victoria C. Barclay
- Center for Infectious Disease Dynamics, Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- * E-mail:
| | - Timo Smieszek
- Center for Infectious Disease Dynamics, Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Jianping He
- Department of Computer Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Guohong Cao
- Department of Computer Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Jeanette J. Rainey
- Division of Global Migration and Quarantine, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Hongjiang Gao
- Division of Global Migration and Quarantine, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Amra Uzicanin
- Division of Global Migration and Quarantine, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Marcel Salathé
- Center for Infectious Disease Dynamics, Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
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Campbell E, Salathé M. Complex social contagion makes networks more vulnerable to disease outbreaks. Sci Rep 2013; 3:1905. [PMID: 23712758 PMCID: PMC3664906 DOI: 10.1038/srep01905] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 05/10/2013] [Indexed: 11/28/2022] Open
Abstract
Social network analysis is now widely used to investigate the dynamics of infectious disease spread. Vaccination dramatically disrupts disease transmission on a contact network, and indeed, high vaccination rates can potentially halt disease transmission altogether. Here, we build on mounting evidence that health behaviors - such as vaccination, and refusal thereof - can spread across social networks through a process of complex contagion that requires social reinforcement. Using network simulations that model health behavior and infectious disease spread, we find that under otherwise identical conditions, the process by which the health behavior spreads has a very strong effect on disease outbreak dynamics. This dynamic variability results from differences in the topology within susceptible communities that arise during the health behavior spreading process, which in turn depends on the topology of the overall social network. Our findings point to the importance of health behavior spread in predicting and controlling disease outbreaks.
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Affiliation(s)
- Ellsworth Campbell
- Center for Infectious Disease Dynamics, Penn State University, University Park, PA, USA.
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10
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Mollema L, Wijers N, Hahné SJM, van der Klis FRM, Boshuizen HC, de Melker HE. Participation in and attitude towards the national immunization program in the Netherlands: data from population-based questionnaires. BMC Public Health 2012; 12:57. [PMID: 22264347 PMCID: PMC3298495 DOI: 10.1186/1471-2458-12-57] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Accepted: 01/20/2012] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Knowledge about the determinants of participation and attitude towards the National Immunisation Program (NIP) may be helpful in tailoring information campaigns for this program. Our aim was to determine which factors were associated with nonparticipation in the NIP and which ones were associated with parents' intention to accept remaining vaccinations. Further, we analyzed possible changes in opinion on vaccination over a 10 year period. METHODS We used questionnaire data from two independent, population-based, cross-sectional surveys performed in 1995-96 and 2006-07. For the 2006-07 survey, logistic regression modelling was used to evaluate what factors were associated with nonparticipation and with parents' intention to accept remaining vaccinations. We used multivariate multinomial logistic regression modelling to compare the results between the two surveys. RESULTS Ninety-five percent of parents reported that they or their child (had) participated in the NIP. Similarly, 95% reported they intended to accept remaining vaccinations. Ethnicity, religion, income, educational level and anthroposophic beliefs were important determinants of nonparticipation in the NIP. Parental concerns that played a role in whether or not they would accept remaining vaccinations included safety of vaccinations, maximum number of injections, whether vaccinations protect the health of one's child and whether vaccinating healthy children is necessary. Although about 90% reported their opinion towards vaccination had not changed, a larger proportion of participants reported to be less inclined to accept vaccination in 2006-07 than in 1995-96. CONCLUSION Most participants had a positive attitude towards vaccination, although some had doubts. Groups with a lower income or educational level or of non-Western descent participated less in the NIP than those with a high income or educational level or indigenous Dutch and have been less well identified previously. Particular attention ought to be given to these groups as they contribute in large measure to the rate of nonparticipation in the NIP, i.e., to a greater extent than well-known vaccine refusers such as specific religious groups and anthroposophics. Our finding that the proportion of the population inclined to accept vaccinations is smaller than it was 10 years ago highlights the need to increase knowledge about attitudes and beliefs regarding the NIP.
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Affiliation(s)
- Liesbeth Mollema
- Centre for Infectious Disease Control Netherlands, RIVM, Bilthoven, The Netherlands
- National Institute for Public Health and the Environment, Centre for Infectious Disease Control Netherlands, Epidemiology and Surveillance Unit, P.O. Box 1, 3720 BA, Bilthoven, The Netherlands
| | - Nancy Wijers
- Centre for Infectious Disease Control Netherlands, RIVM, Bilthoven, The Netherlands
- Department of Earth and Life Science, VU University Amsterdam, Amsterdam, The Netherlands
| | - Susan JM Hahné
- Centre for Infectious Disease Control Netherlands, RIVM, Bilthoven, The Netherlands
| | | | - Hendriek C Boshuizen
- ICT/Expertise Centre for Methodology and Information Service, RIVM, Bilthoven, The Netherlands
| | - Hester E de Melker
- Centre for Infectious Disease Control Netherlands, RIVM, Bilthoven, The Netherlands
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11
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Development of a bead-based multiplex immunoassay for simultaneous quantitative detection of IgG serum antibodies against measles, mumps, rubella, and varicella-zoster virus. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2012; 19:396-400. [PMID: 22237896 DOI: 10.1128/cvi.05537-11] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Enzyme-linked immunosorbent assay (ELISA) is normally used to quantify the amount of serum IgG antibodies against measles, mumps, rubella, and varicella-zoster virus (MMRV). However, this method is time- and material-consuming. Therefore, a multiplex immunoassay for the simultaneous quantitative detection of antibodies against MMRV was developed. In-house as well as commercially available antigens can be used, making the assay available for all laboratories. The multiplex assay is much more sensitive than the separate ELISAs and has a high specificity, and only 5 μl of serum is needed. Heterologous inhibition did not exceed 11.5%, while homologous inhibition varied between 91.3 and 97.9%. Good correlations with the in-house ELISAs for measles (R(2) = 0.98), mumps (R(2) = 0.97), and rubella (R(2) = 0.97) virus as well as with the ELISA kit for varicella-zoster virus (R(2) = 0.95) were obtained. In conclusion, the MMRV multiplex assay is a good alternative to the conventional ELISAs and suitable for use in serosurveillance and vaccine studies.
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Hahne S, te Wierik MJM, Mollema L, van Velzen E, de Coster E, Swaan C, de Melker H, van Binnendijk R. Measles outbreak, the Netherlands, 2008. Emerg Infect Dis 2010; 16:567-9. [PMID: 20202450 DOI: 10.3201/eid1603.090114] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Hahne S, te Wierik MJM, Mollema L, van Velzen E, de Coster E, Swaan C, de Melker H, van Binnendijk R. Measles outbreak, the Netherlands, 2008. Emerg Infect Dis 2010. [PMID: 20202450 PMCID: PMC3322001 DOI: 10.3201/eid1602.090114] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Curtale F, Perrelli F, Mantovani J, Atti MCD, Filia A, Nicoletti L, Magurano F, Borgia P, Di Lallo D. Description of two measles outbreaks in the Lazio Region, Italy (2006-2007). Importance of pockets of low vaccine coverage in sustaining the infection. BMC Infect Dis 2010; 10:62. [PMID: 20219143 PMCID: PMC3161360 DOI: 10.1186/1471-2334-10-62] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2009] [Accepted: 03/11/2010] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Despite the launch of the national plan for measles elimination, in Italy, immunization coverage remains suboptimal and outbreaks continue to occur. Two measles outbreaks, occurred in Lazio region during 2006-2007, were investigated to identify sources of infection, transmission routes, and assess operational implications for elimination of the disease. METHODS Data were obtained from several sources, the routine infectious diseases surveillance system, field epidemiological investigations, and molecular genotyping of virus by the national reference laboratory. RESULTS Overall 449 cases were reported, sustained by two different stereotypes overlapping for few months. Serotype D4 was likely imported from Romania by a Roma/Sinti family and subsequently spread to the rest of the population. Serotype B3 was responsible for the second outbreak which started in a secondary school. Pockets of low vaccine coverage individuals (Roma/Sinti communities, high school students) facilitated the reintroduction of serotypes not endemic in Italy and facilitated the measles infection to spread. CONCLUSIONS Communities with low vaccine coverage represent a more serious public health threat than do sporadic susceptible individuals. The successful elimination of measles will require additional efforts to immunize low vaccine coverage population groups, including hard-to-reach individuals, adolescents, and young adults. An enhanced surveillance systems, which includes viral genotyping to document chains of transmission, is an essential tool for evaluating strategy to control and eliminate measles.
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Affiliation(s)
- Filippo Curtale
- Unit of Infecious Diseases and Vaccination, Department of Health Prevention and Promotion, Laziosanita' Agenzia di Sanita' Pubblica (ASP), Via Santa Costanza 53, 00198 Roma, Italy
| | - Fabrizio Perrelli
- Unit of Infecious Diseases and Vaccination, Department of Health Prevention and Promotion, Laziosanita' Agenzia di Sanita' Pubblica (ASP), Via Santa Costanza 53, 00198 Roma, Italy
| | - Jessica Mantovani
- Unit of Infecious Diseases and Vaccination, Department of Health Prevention and Promotion, Laziosanita' Agenzia di Sanita' Pubblica (ASP), Via Santa Costanza 53, 00198 Roma, Italy
| | - Marta Ciofi degli Atti
- Unit of Epidemiology and Bio-Statistics, Healthcare Department, The Bambino Gesù Children's Hospital, Piazza S Onofrio 4, 00165 Rome, Italy
| | - Antonietta Filia
- National Centre for Epidemiology, Surveillance and Health Promotion (CNESPS), Istituto Superiore di Sanità (ISS), Via Giano della Bella 34 - 00162 Rome, Italy
| | - Loredana Nicoletti
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Fabio Magurano
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Piero Borgia
- Scientific Directorate, Laziosanita' Agenzia di Sanita' Pubblica, Via Santa Costanza 53, 00198 Rome, Italy
| | - Domenico Di Lallo
- Department of Health Prevention and Promotion, Laziosanita' Agenzia di Sanita' Pubblica, Via Santa Costanza 53, 00198 Rome, Italy
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Timmermans DRM, Henneman L, Hirasing RA, van der Wal G. Parents' perceived vulnerability and perceived control in preventing Meningococcal C infection: a large-scale interview study about vaccination. BMC Public Health 2008; 8:45. [PMID: 18241345 PMCID: PMC2279114 DOI: 10.1186/1471-2458-8-45] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Accepted: 02/01/2008] [Indexed: 11/10/2022] Open
Abstract
Background Parents' reported ambivalence toward large-scale vaccination programs for childhood diseases may be related to their perception of the risks of side-effects or safety of vaccination and the risk of contracting the disease. The aim of this study is to evaluate parents' perceptions of their child's risk contracting a Meningococcal C infection and parents' perceived control in preventing infection in relation to their evaluation of the safety, effectiveness and usefulness of vaccination. Methods In a large-scale interview study, a random sample of parents was interviewed after their children had received vaccination against Meningococcal C in a catch-up campaign. Questions were asked about the perceived relative vulnerability of their child contracting an infection, perceived control in preventing an infection, and parents' evaluation of the safety, usefulness and effectiveness of vaccination. Results 61% of 2910 (N = 1763) parents who were approached participated. A higher perceived relative vulnerability of their own child contracting the disease was related to a more positive evaluation of the vaccination campaign, while a lower perceived vulnerability did not result in a more negative evaluation. A higher perceived control in being able to prevent an infection was, however, related to a more critical attitude toward the safety, usefulness and effectiveness of vaccination. Conclusion Perceived relative vulnerability contracting an infection and parents' perceived control in preventing an infection seem to influence parents' evaluation of the vaccination programme. Future studies should determine if, and under which circumstances, these perceptions also affect parents' vaccination behaviour and would be relevant to be taken into account when educating parents about vaccination.
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Affiliation(s)
- Danielle R M Timmermans
- Department of Public and Occupational Health, EMGO Institute, VU University Medical Center, Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands.
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Stein-Zamir C, Zentner G, Abramson N, Shoob H, Aboudy Y, Shulman L, Mendelson E. Measles outbreaks affecting children in Jewish ultra-orthodox communities in Jerusalem. Epidemiol Infect 2008; 136:207-14. [PMID: 17433131 PMCID: PMC2870804 DOI: 10.1017/s095026880700845x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/07/2007] [Indexed: 11/07/2022] Open
Abstract
In 2003 and 2004 two measles outbreaks occurred in Jewish ultra-orthodox communities in Jerusalem. The index case of the first outbreak (March 2003) was a 2-year-old unvaccinated child from Switzerland. Within 5 months, 107 cases (mean age 8.3+/-7.5 years) emerged in three crowded neighbourhoods. The first cases of the second outbreak (June 2004) were in three girls aged 4-5 years in one kindergarten in another community. By November 2004, 117 cases (mean age 7.3+/-6.5 years) occurred. The virus genotypes were D8 and D4 respectively. Altogether, 96 households accounted for the two outbreaks, with two or more patients per family in 79% of cases. Most cases (91.5%) were unvaccinated. Immunization coverage was lower in outbreak than in non-outbreak neighbourhoods (88.3% vs. 90.3%, P=0.001). Controlling the outbreaks necessitated a culture-sensitive approach, and targeted efforts increased MMR vaccine coverage (first dose) to 95.2%. Despite high national immunization coverage (94-95%), special attention to specific sub-populations is essential.
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Affiliation(s)
- C Stein-Zamir
- Jerusalem District Health Office, Ministry of Health, Jerusalem, Israel.
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Wallinga J, Heijne JCM, Kretzschmar M. A measles epidemic threshold in a highly vaccinated population. PLoS Med 2005; 2:e316. [PMID: 16218769 PMCID: PMC1255760 DOI: 10.1371/journal.pmed.0020316] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2005] [Accepted: 08/02/2005] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Mass vaccination against measles has successfully lowered the incidence of the disease and has changed the epidemic pattern from a roughly biennial cycle to an irregular sequence of outbreaks. A possible explanation for this sequence of outbreaks is that the vaccinated population is protected by solid herd immunity. If so, we would expect to see the fraction of susceptible individuals remaining below an epidemic threshold. An alternative explanation is the occurrence of occasional localised lapses in herd immunity that allow for major outbreaks in areas with a low vaccine coverage. In that case, we would expect the fraction of susceptible individuals to exceed an epidemic threshold before outbreaks occur. These two explanations for the irregular sequence of measles outbreaks can be tested against observations of both the fraction of susceptible individuals and infection attack rates. METHODS AND FINDINGS We have estimated both the fraction of susceptible individuals at the start of each epidemic year and the infection attack rates for each epidemic year in the Netherlands over a 28-y period. During this period the vaccine coverage averaged 93%, and there was no sustained measles transmission. Several measles outbreaks occurred in communities with low vaccine coverage, and these ended without intervention. We show that there is a clear threshold value for the fraction of susceptible individuals, below which only minor outbreaks occurred, and above which both minor and major outbreaks occurred. A precise, quantitative relationship exists between the fraction of susceptible individuals in excess of this threshold and the infection attack rate during the major outbreaks. CONCLUSION In populations with a high but heterogeneous vaccine coverage, measles transmission can be interrupted without establishing solid herd immunity. When infection is reintroduced, a major outbreak can occur in the communities with low vaccine coverage. During such a major outbreak, each additional susceptible individual in excess of the threshold is associated with almost two additional infections. This quantitative relationship offers potential for anticipating both the likelihood and size of future major outbreaks when measles transmission has been interrupted.
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Affiliation(s)
- Jacco Wallinga
- Centre for Infectious Disease Epidemiology, National Institute for Public Health and the Environment, Bilthoven, The Netherlands.
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