Pneumococcal carriage following PCV13 delivered as one primary and one booster dose (1 + 1) compared to two primary doses and a booster (2 + 1) in UK infants.

In January 2020 the UK changed from a 2 + 1 schedule for 13-valent pneumococcal conjugate vaccine (PCV13) to a 1 + 1 schedule (doses at 3 and 12 months) based on a randomized immunogenicity trial comparing the two schedules. Carriage prevalence measured at the time of booster and 6 months later in 191 of the 213 study infants was 57 % (109/191) and 60 % (114/190) respectively. There were eight episodes of vaccine-type (VT) or vaccine-related 6C carriage in the 2 + 1 and six in the 1 + 1 group; ≥4-fold rises in serotype-specific IgG in 71 children with paired post-booster and follow up blood samples at 21-33 months of age were found in 20 % (7/35) of the 2 + 1 and 15 % (6/41) of the 1 + 1 group. VTs identified in carriage and inferred from serology were similar comprising 3, 19A and 19F. Dropping a priming dose from the 2 + 1 PCV 13 schedule did not increase VT carriage in the study cohort. Ongoing population level carriage studies will be important to confirm this.

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Déclaration de conflit d'intérêts

Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Matthew Snape reports financial support was provided by National Institute for Health and Care Research. David Goldblatt reports financial support was provided by Bill & Melinda Gates Foundation. NA, CLS, SR and DJL have no conflicts of interest. The UKHSA Immunisation and Vaccine Preventable Diseases (previously Public Health England) has provided vaccine manufactures with post-marketing surveillance reports, which the Marketing Authorization Holders are required to submit to the UK Licensing authority in compliance with their Risk Management Strategy. A cost recovery charge is made for these reports. JS, NF, EM declare no other conflicts of interest although since this work was completed JS has left PHE and now works for Pfizer. During the trial MDS acted on behalf of the University of Oxford and Oxford Vaccine Group (OVG) as Chief or Principal Investigator on clinical trials sponsored and/or funded by vaccine manufacturers including Pfizer and GSK. He received no personal payment for this work. MDS is now an employee of Moderna Biotech UK. JS was an employee of PHE (now UKHSA) during conduct of the work and is currently an employee of Pfizer Inc. and may own stock or stock options. PA, HR and EP are employed by the OVG. DG has served on ad hoc advisory boards for GSK, Merck and Sanofi and is a National Institute of Health Research (NIHR) Senior Investigator. The UCL GOSICH Lab (DG, LR, EP, MJ) has received contract research funding from GSK, Merck and Sanofi.