Inequalities in childhood pneumococcal conjugate vaccine uptake in England before and after the change from a 2 + 1 to 1 + 1 schedule: a longitudinal study.

Abstract

Introducing pneumococcal conjugate vaccines (PCVs) into England's childhood immunisation schedule has reduced pneumococcal disease. Nonetheless, pneumococcal disease burden persists, including in young children. In January 2020, England replaced the '2 + 1' PCV schedule (two primary doses at 8 and 16 weeks, booster dose at 12 months) with a '1 + 1' PCV schedule (primary dose at 12 weeks, booster dose at 12 months). Although immunogenicity studies suggested comparable protection, the reduced-dose schedule increases reliance on timely booster uptake. We examined national trends in PCV uptake before and after the schedule change and quantified inequalities by deprivation. We analysed quarterly vaccine uptake data for 2013-2025 from COVER (Cover of Vaccination Evaluated Rapidly) for upper-tier local authorities in England, linked to 2019 Index of Multiple Deprivation quintiles. We examined booster gaps-difference between primary coverage at 12 months and booster coverage at 24 months. We estimated susceptibility to vaccine-type invasive pneumococcal disease by birth cohort and quarter, combining observed PCV uptake with published vaccine effectiveness estimates. Booster retention deteriorated following the schedule change; mean booster gaps increased from 2.32% (2 + 1 period) to 4.79% (1 + 1 period). Inequalities widened, with differences between least and most deprived quintiles increasing from 2-3% to 4-6%. Estimated susceptibility showed marked geographical variation, with higher burden in deprived areas. The success of the 1 + 1 schedule depends on maintaining equitable, high booster uptake. Declining booster retention and widening inequalities risk undermining impact, highlighting the need for targeted support and strengthened follow-up systems. No specific funding.