Single priming and a booster dose of 10-valent and 13-valent pneumococcal conjugate vaccine (PCV) maintains suppression of vaccine serotype colonization in South African children at 3, 4, and 5 years of age: a single-centre, open-labelled, randomized trial.

Abstract

Background: Surveillance on nasopharyngeal Streptococcus pneumoniae carriage in older children would be informative in determining whether a single priming and booster dose of pneumococcal conjugate vaccine (PCV) provides durable protection against pneumococcal disease compared with traditional dosing schedules.

Methods and objectives: We report on the secondary study objective to evaluate overall, vaccine-serotype (VT), and non-vaccine serotype (NVT) S. pneumoniae colonization at 3, 4, and 5 years of age in children who were randomized to receive 10-valent or 13-valent PCV formulations at 6 (6w + 1) or 14 (14w + 1) weeks compared with a two-dose primary series (2 + 1), with all children receiving a booster dose at 9 months of age, using a multiplex nanofluidic qPCR assay.

Results: The prevalence of overall, VT, or NVT at 5 years of age between the 2 + 1 compared with the 6w + 1 or 14w + 1 groups for both PCV10 and PCV13 did not differ.

Conclusion: Although inconclusive, our findings suggest that a reduced 1 + 1 PCV dosing schedule is unlikely to increase breakthrough cases of VT pneumococcal disease in older children, which can inform decision-making on transitioning to a 1 + 1 schedule in South Africa.Clinical trial registration: The trial is registered at www.clinicaltrials.gov (identifier is NCT04275284).