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Shrestha S, Stockdale LK, Gautam MC, Gurung M, Feng S, Maskey P, Kerridge S, Kelly S, Voysey M, Pokhrel B, Rajbhandari P, Thorson S, Khadka B, Shah G, Scherer KS, Kelly D, Murdoch DR, Shrestha S, Pollard AJ. Impact of Vaccination on Haemophilus influenzae Type b Carriage in Healthy Children Less Than 5 Years of Age in an Urban Population in Nepal. J Infect Dis 2021; 224:S267-S274. [PMID: 34469554 PMCID: PMC8409530 DOI: 10.1093/infdis/jiab072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Background Reduction in detection of asymptomatic carriage of Haemophilus influenzae type b (Hib) can be used to assess vaccine impact. In Nepal, routine vaccination against Hib in children at 6, 10, and 14 weeks of age was introduced in 2009. Before vaccine introduction, Hib carriage was estimated at 5.0% among children aged <13 years in Nepal, with higher rates among children under 5. Large-scale evaluation of Hib carriage in children has not been investigated since the introduction of the pentavalent diphtheria-tetanus-pertussis/Hib/hepatitis B (DTP-Hib-HepB) vaccine in Nepal. Methods A total of 666 oropharyngeal swabs were collected between August and December 2018 from healthy children between 6 months and 5 years of age attending the vaccination clinic at Patan Hospital, Kathmandu, Nepal. Of these 666 swabs, 528 (79.3%) were tested for Hib by culture. Demographic and vaccination data were collected. Results Among 528 swabs tested for Hib, 100% came from fully vaccinated children. No swabs were positive for Hib (95% confidence interval, .0–.7). The absence of Hib in 2018 suggests vaccine-induced protection against Hib carriage 9 years after vaccine introduction. Conclusions Following 3 doses of pentavalent DTP-Hib-HepB vaccine, Hib carriage in children under the age of 5 years in Nepal is no longer common. Ongoing high coverage with Hib vaccine in early childhood is expected to maintain protection against Hib disease in Nepal.
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Affiliation(s)
- Sonu Shrestha
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Lisa K Stockdale
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Madhav C Gautam
- Pediatric Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Meeru Gurung
- Pediatric Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Shuo Feng
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Pratistha Maskey
- Pediatric Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Simon Kerridge
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Sarah Kelly
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Merryn Voysey
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Bhishma Pokhrel
- Pediatric Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Piyush Rajbhandari
- Microbiology Unit, Department of Pathology and Laboratory Medicine, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Stephen Thorson
- Pediatric Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Bibek Khadka
- Pediatric Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Ganesh Shah
- Pediatric Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Karin S Scherer
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Dominic Kelly
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - David R Murdoch
- Department of Pathology and Biomedical Science, University of Otago, Christchurch, New Zealand
| | - Shrijana Shrestha
- Pediatric Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom
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Study of Serologic Response Rate to Haemophilus influenzae Type B After Administration of the Third Dose of Pentavalent Vaccine in Children Aged 12 Months in Karaj City in 2016. ARCHIVES OF CLINICAL INFECTIOUS DISEASES 2018. [DOI: 10.5812/archcid.59344] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Kim HW, Kim KH, Kim J, Nahm MH. A high throughput serum bactericidal assay for antibodies to Haemophilus influenzae type b. BMC Infect Dis 2016; 16:473. [PMID: 27595992 PMCID: PMC5011942 DOI: 10.1186/s12879-016-1808-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 08/26/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The protective capacities of antibodies induced with Haemophilus influenzae type b (Hib) vaccines can be directly assessed in vitro with a Hib-specific serum bactericidal assay (SBA). However, the conventional SBA requires several tedious steps including manual counting of bacterial colonies, and therefore, it is seldom used. METHODS To overcome these limitations, we have improved the conventional SBA by using frozen target bacteria and by developing an automated colony counting method based on agar plates with the chromogenic dye 2, 3, 5-triphenyl tetrazolium chloride (TTC). RESULTS These changes enabled us to analyze about 100 serum samples per day per person by SBA. When the intra- and inter-assay precisions were studied, this assay showed a coefficient of variation (CV) ranging from 1 to 38 %. To monitor the long term assay stability for assays involving different bacteria lots, complement lots, and operators, we analyzed bactericidal indices of quality control samples obtained over a 6 year period and found the CV to be about 35-50 %. Lastly, our SBA results were compared with the ELISA results obtained using 90 serum samples from children. We showed that the bactericidal index correlated with IgG anti-Hib antibody levels (r = 0.84), with a bactericidal index of 10 corresponding approximately to 0.15 μg/mL IgG, the widely accepted protective level of antibody. CONCLUSION We describe a simple high throughput SBA for anti-Hib antibodies that would be useful for evaluating various Hib vaccines. While additional work will be needed to standardize the assay, this SBA should greatly facilitate studies of Hib vaccines.
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Affiliation(s)
- Han Wool Kim
- Center for Vaccine Evaluation and Study, Medical Research Institute, School of Medicine, Ewha Womans University, Seoul, Republic of Korea
| | - Kyung-Hyo Kim
- Center for Vaccine Evaluation and Study, Medical Research Institute, School of Medicine, Ewha Womans University, Seoul, Republic of Korea
- Department of Pediatrics, School of Medicine, Ewha Womans University, Seoul, Republic of Korea
| | - JiHye Kim
- Department of Pediatrics, School of Medicine, Ewha Womans University, Seoul, Republic of Korea
| | - Moon H. Nahm
- Department of Pathology and Microbiology, University of Alabama at Birmingham, Birmingham, AL USA
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Hammitt LL, Crane RJ, Karani A, Mutuku A, Morpeth SC, Burbidge P, Goldblatt D, Kamau T, Sharif S, Mturi N, Scott JAG. Effect of Haemophilus influenzae type b vaccination without a booster dose on invasive H influenzae type b disease, nasopharyngeal carriage, and population immunity in Kilifi, Kenya: a 15-year regional surveillance study. LANCET GLOBAL HEALTH 2016; 4:e185-94. [PMID: 26853149 PMCID: PMC4763163 DOI: 10.1016/s2214-109x(15)00316-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 11/18/2015] [Accepted: 12/07/2015] [Indexed: 10/25/2022]
Abstract
BACKGROUND Haemophilus influenzae type b (Hib) conjugate vaccine, delivered as a three-dose series without a booster, was introduced into the childhood vaccination programme in Kenya in 2001. The duration of protection and need for a booster dose are unknown. We aimed to assess vaccine effectiveness, the impact of the vaccine on nasopharyngeal carriage, and population immunity after introduction of conjugate Hib vaccine in infancy without a booster dose in Kenya. METHODS This study took place in the Kilifi Health and Demographic Surveillance System (KHDSS), an area of Kenya that has been monitored for vital events and migration every 4 months since 2000. We analysed sterile site cultures for H influenzae type b from children (aged ≤12 years) admitted to the Kilifi County Hospital (KCH) from Jan 1, 2000, through to Dec 31, 2014. We determined the prevalence of nasopharyngeal carriage by undertaking cross-sectional surveys in random samples of KHDSS residents (of all ages) once every year from 2009 to 2012, and measured Hib antibody concentrations in five cross-sectional samples of children (aged ≤12 years) within the KHDSS (in 1998, 2000, 2004-05, 2007, and 2009). We calculated incidence rate ratios between the prevaccine era (2000-01) and the routine-use era (2004-14) and defined vaccine effectiveness as 1 minus the incidence rate ratio, expressed as a percentage. FINDINGS 40,482 children younger than 13 years resident in KHDSS were admitted to KCH between 2000 and 2014, 38,206 (94%) of whom had their blood cultured. The incidence of invasive H influenzae type b disease in children younger than 5 years declined from 62·6 (95% CI 46·0-83·3) per 100,000 in 2000-01 to 4·5 (2·5-7·5) per 100,000 in 2004-14, giving a vaccine effectiveness of 93% (95% CI 87-96). In the final 5 years of observation (2010-14), only one case of invasive H influenzae type b disease was detected in a child younger than 5 years. Nasopharyngeal H influenzae type b carriage was detected in one (0·2%) of 623 children younger than 5 years between 2009 and 2012. In the 2009 serosurvey, 92 (79%; 95% CI 70-86) of 117 children aged 4-35 months had long-term protective antibody concentrations. INTERPRETATION In this region of Kenya, use of a three-dose primary series of Hib vaccine without a booster dose has resulted in a significant and sustained reduction in invasive H influenzae type b disease. The prevalence of nasopharyngeal carriage is low and the profile of Hib antibodies suggests that protection wanes only after the age at greatest risk of disease. Although continued surveillance is important to determine whether effective control persists, these findings suggest that a booster dose is not currently required in Kenya. FUNDING Gavi, the Vaccine Alliance, Wellcome Trust, European Society for Paediatric Infectious Diseases, and National Institute for Health Research.
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Affiliation(s)
- Laura L Hammitt
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya; Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
| | - Rosie J Crane
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya; Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Angela Karani
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
| | - Alex Mutuku
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
| | - Susan C Morpeth
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya; Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK; Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
| | - Polly Burbidge
- Institute of Child Health, University College London, London, UK
| | - David Goldblatt
- Institute of Child Health, University College London, London, UK
| | - Tatu Kamau
- Kenya Ministry of Public Health and Sanitation, Kilifi, Kenya
| | - Shahnaaz Sharif
- Kenya Ministry of Public Health and Sanitation, Kilifi, Kenya
| | - Neema Mturi
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
| | - J Anthony G Scott
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya; Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK; Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
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Marshall ASJ, Barker CIS, Pulickal AS, Kibwana E, Gautam SC, Clutterbuck EA, Thorson SM, Shrestha S, Adhikari N, Pollard AJ, Kelly DF. The seroepidemiology of Haemophilus influenzae type b prior to introduction of an immunization programme in Kathmandu, Nepal. PLoS One 2014; 9:e85055. [PMID: 24465475 PMCID: PMC3898912 DOI: 10.1371/journal.pone.0085055] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2013] [Accepted: 11/21/2013] [Indexed: 11/19/2022] Open
Abstract
Haemophilus influenzae type b (Hib) is now recognized as an important pathogen in Asia. To evaluate disease susceptibility, and as a marker of Hib transmission before routine immunization was introduced in Kathmandu, 71 participants aged 7 months-77 years were recruited and 15 cord blood samples were collected for analysis of anti-polyribosylribitol phosphate antibody levels by enzyme-linked immunosorbent assay. Only 20% of children under 5 years old had levels considered protective (>0.15 µg/ml), rising to 83% of 15-54 year-olds. Prior to introduction of Hib vaccine in Kathmandu, the majority of young children were susceptible to disease.
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Affiliation(s)
- Andrew S. J. Marshall
- Oxford Vaccine Group, Oxford University, and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
- * E-mail:
| | - Charlotte I. S. Barker
- Oxford Vaccine Group, Oxford University, and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Anoop S. Pulickal
- Oxford Vaccine Group, Oxford University, and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Elizabeth Kibwana
- Oxford Vaccine Group, Oxford University, and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | | | - Elizabeth A. Clutterbuck
- Oxford Vaccine Group, Oxford University, and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | | | | | | | - Andrew J. Pollard
- Oxford Vaccine Group, Oxford University, and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Dominic F. Kelly
- Oxford Vaccine Group, Oxford University, and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
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Hutter J, Pasetti MF, Sanogo D, Tapia MD, Sow SO, Levine MM. Naturally acquired and conjugate vaccine-induced antibody to Haemophilus influenzae type b (Hib) polysaccharide in Malian children: serological assessment of the Hib immunization program in Mali. Am J Trop Med Hyg 2012; 86:1026-31. [PMID: 22665612 DOI: 10.4269/ajtmh.2012.11-0807] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Haemophilus influenzae type b (Hib) conjugate vaccine for infants (6, 10, and 14 weeks of age) was introduced into the Malian Expanded Program on Immunization in July 2005, to diminish invasive Hib disease in young children. Antibodies to Hib capsular polysaccharide (PRP) were measured in infants and toddlers from an area already served by the Hib immunization program (Bamako) and in unimmunized children of the same age in a district (Kangaba) where Hib immunization had not yet begun. Among vaccinated Bamako children 6-23 months of age, 77-93% exhibited PRP titers ≥ 1.0 μg/mL, indicating long-term protection, versus only 10-23% of Kangaba children of that age. High PRP antibody titers in immunized children persisted through 2 years of age. Moreover, ∼50% of Bamako children exhibited anti-PRP titers ≥ 5.0 μg/mL; a level that impedes Hib upper respiratory carriage, and may thereby diminish the Hib transmission to the unimmunized susceptible population (i.e., providing indirect protection).
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Affiliation(s)
- Julia Hutter
- Center for Vaccine Development and the Departments of Pediatrics and Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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Abstract
BACKGROUND Haemophilus influenzae type b (Hib) carriage and disease studies in Nepali children suggest a significant burden of infection. Hib conjugate vaccines (HibCV) do not have uniform immunogenicity between populations. We determined the immunogenicity of HibCV in Nepali infants, before its introduction into the routine immunization schedule. METHODS Ninety infants recruited at Patan Hospital, Kathmandu, received 3 doses of the HibCV with routine immunizations (diphtheria, tetanus, whole cell pertussis-hepatitis B vaccine + oral polio vaccine) at 6, 10 and 14 weeks of age, and a HibCV booster at 52 weeks. Anti-polyribosylribitol phosphate (PRP) concentrations were measured at 18, 52 and 56 weeks, and the antibody persistence at 52 weeks was compared with antibody values in unimmunized controls (n = 30). RESULTS After 3 doses of primary immunizations, at 18 weeks of age (n = 74), all infants had anti-PRP concentrations above the accepted thresholds for short- and long-term protection (0.15 and 1.0 µg/mL, respectively). At 1 year of age, before administration of the booster of HibCV, the anti-PRP geometric mean antibody concentration was 2.76 µg/mL (confidence interval: 1.88-4.07) in sera from the immunized children compared with 0.11 µg/mL (95% confidence interval: 0.08-0.17) in the nonimmunized control group (n = 30). Twenty-seven percent (20/74) of participants, however, had anti-PRP concentrations <1.0 µg/mL. Four weeks after the booster dose of HibCV, 98.5% of infants had anti-PRP concentrations above 1.0 µg/mL. CONCLUSION Immunization with HibCV given as part of the Expanded Program on Immunization schedule in Nepal elicits robust antibody responses. Though the antibody wanes during the first year of life, most 1-year-old infants remain protected and respond robustly to a booster dose of the vaccine.
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Recurrent bacterial meningitis by three different pathogens in an isolated asplenic child. J Infect Chemother 2011; 18:576-80. [PMID: 22147274 DOI: 10.1007/s10156-011-0341-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Accepted: 10/25/2011] [Indexed: 10/15/2022]
Abstract
Isolated congenital asplenia (ICA) is a rare condition at risk for overwhelming infection. When complicated by invasive infection, the mortality remains high, at greater than 60%. We describe a girl with ICA who developed recurrent meningitis by three different pathogens. The first, meningitis by Escherichia coli, occurred 4 days after premature birth. The other two pathogens were serotype 6B Streptococcus pneumoniae and Haemophilus influenzae type b (Hib), at 18 and 25 months of age, respectively. The patient was successfully treated with prompt antimicrobial therapy in all episodes. Serum anti-polyribosylribitol phosphate (PRP) and anti-6B-type pneumococcal antibodies were below the levels for protective activity after natural infections. Although anti-PRP antibody was significantly increased after Hib vaccination, two (6B and 19F) of seven serotype-specific pneumococcal antibodies were not elevated to protective levels after the second 7-valent pneumococcal conjugate vaccine (PCV7). We, therefore, added a third PCV7. To our knowledge, this is the first neonatal ICA patient with invasive infection and the first case of bacterial meningitis occurring three times. Our findings indicate that monitoring of immune responses after natural infections and vaccinations, and reevaluations of vaccine schedule, are important for ICA patients to prevent subsequent invasive infections.
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Gómez de León Cruces P, Díaz García J, Santos JI. Effect of the DTwP Haemophilus influenzae b Conjugate Vaccination in Mexico (1999–2007). Arch Med Res 2010; 41:281-7. [DOI: 10.1016/j.arcmed.2010.05.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Accepted: 05/24/2010] [Indexed: 11/28/2022]
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