IMMUNOGENICITY AND IMPACT ON NASOPHARYNGEAL CARRIAGE OF A SINGLE DOSE OF PCV10 GIVEN TO VIETNAMESE CHILDREN AT 18 MONTHS OF AGE.

Rachel A Higgins,Kathryn Bright,Leena Spry,Jason Hinds,Tran Ngoc Huu,Catherine Satzke,Zheng Quan Toh,Beth Temple,Vo Thi Trang Dai,Anne Balloch,Doan Y Uyen,Yin Bun Cheung,Kim Mulholland,Belinda D Ortika ,Heidi Smith‐Vaughan ,Nguyễn Trọng Toàn ,Thanh Vân Phan ,Cattram Nguyen ,Monica Larissa Nation ,Paul V Licciardi

doi:10.1016/j.lanwpc.2021.100273

Abstract

BackgroundThis study investigated the immunogenicity and impact on nasopharyngeal carriage of a single dose of PCV10 given to 18-month-old Vietnamese children. This information is important for countries considering catch-up vaccination during PCV introduction and in the context of vaccination during humanitarian crises.MethodsTwo groups of PCV-naïve children within the Vietnam Pneumococcal Project received PCV10 (n=197) or no PCV (unvaccinated; n=199) at 18 months of age. Blood samples were collected at 18, 19, and 24 months of age, and nasopharyngeal swabs at 18 and 24 months of age. Immunogenicity was assessed by measuring serotype-specific IgG, opsonophagocytosis (OPA) and memory B cells (Bmem). Pneumococci were detected and quantified using real-time PCR and serotyped by microarray.FindingsAt 19 months of age, IgG and OPA responses were higher in the PCV10 group compared with the unvaccinated group for all PCV10 serotypes and cross-reactive serotypes 6A and 19A. This was sustained out to 24 months of age, at which point PCV10-type carriage was 60% lower in the PCV10 group than the unvaccinated group. Bmem levels increased between 18 and 24 months of age in the vaccinated group.InterpretationWe demonstrate strong protective immune responses in vaccinees following a single dose of PCV10 at 18 months of age, and a potential impact on herd protection through a substantial reduction in vaccine-type carriage. A single dose of PCV10 in the second year of life could be considered as part of catch-up campaigns or in humanitarian crises to protect children at high-risk of pneumococcal disease.

Highlights

Streptococcus pneumoniae is a leading cause of mortality and morbidity in children less than five years of age worldwide.[1]
Between 30 September 2013 and 9 January 2015, 197 infants were enrolled at two months of age and allocated to receive a single dose of PCV10 at 18 months of age as part of the Vietnam Pneumococcal Project
We found that a single dose of PCV10 at 18 months of age induced strong antibody responses by ELISA to all vaccine and cross-reactive serotypes, and strong functional antibody responses by OPA to most serotypes

Summary

Introduction

Streptococcus pneumoniae (the pneumococcus) is a leading cause of mortality and morbidity in children less than five years of age worldwide.[1]. This study investigated the immunogenicity and impact on nasopharyngeal carriage of a single dose of PCV10 given to 18-month-old Vietnamese children. This information is important for countries considering catch-up vaccination during PCV introduction and in the context of vaccination during humanitarian crises. Findings: At 19 months of age, IgG and OPA responses were higher in the PCV10 group compared with the unvaccinated group for all PCV10 serotypes and cross-reactive serotypes 6A and 19A This was sustained out to 24 months of age, at which point PCV10-type carriage was 60% lower in the PCV10 group than the unvaccinated group. A single dose of PCV10 in the second year of life could be considered as part of catch-up campaigns or in humanitarian crises to protect children at high-risk of pneumococcal disease

Methods

Results

Conclusion