Study Supports Reduced-Dose PCV13 Vaccination Schedule with Protection Lasting Through Early Childhood

Study Supports Reduced-Dose PCV13 Vaccination Schedule with Protection Lasting Through Early Childhood

JOHANNESBURG, South Africa

New research from Wits Vaccines and Infectious Diseases Analytics Research Unit (Wits VIDA), University of the Witwatersrand, suggests that children receiving a reduced-dose schedule of the 13-valent pneumococcal conjugate vaccine (PCV13) maintain immune protection through five years of age comparable to that achieved with the currently recommended schedule. The findings provide important evidence for countries considering more efficient vaccine programmes while maintaining protection against serious pneumococcal disease.

The study, led by researchers from Wits VIDA and international collaborators, is the first to evaluate long-term antibody persistence through five years of age following reduced-dose pneumococcal vaccination schedules using both 10-valent (PCV10) and 13-valent (PCV13) vaccines.

Pneumococcal disease remains a major cause of severe illness in children worldwide, causing conditions such as pneumonia, meningitis, and bloodstream infections. While the World Health Organisation currently recommends either three primary doses or a two-dose primary series plus a booster dose, several countries have begun exploring a reduced-dose “1+1” schedule consisting of a single infant dose followed by a booster.

The South African study followed children who had been randomly assigned during infancy to receive either a standard two-dose primary series plus booster (2+1 schedule) or a reduced-dose schedule (1+1 schedule) of PCV10 or PCV13. Researchers measured vaccine-induced antibody levels annually at three, four and five years of age.

Among children vaccinated with PCV13, the immune responses in children who received the 1+1 dose was similar to those who received the 2+1 dosing schedule through to five years of age. The strongest antibody persistence was observed when the single infant priming dose was administered at 14 weeks of age rather than six weeks. In contrast, the PCV10 1+1 group had greater waning of immunity than the 2+1 group at four and five years.

“The results provide robust evidence that a PCV13 one-primary-dose plus booster schedule can sustain immune responses through the first five years of life,” said Professor Shabir A. Madhi, Director of Wits VIDA. “These findings are particularly relevant for countries with mature, high-coverage immunisation programmes that are seeking to maximise the impact and sustainability of childhood vaccination.”

According to the researchers, reducing the number of primary vaccine doses could offer significant programmatic advantages, including lower procurement and administration costs and reduced pressure on childhood immunisation schedules. These savings could potentially create fiscal space for the introduction of newer, broader-coverage pneumococcal vaccines in low- and middle-income countries.

The study addresses a key evidence gap previously highlighted in a World Health Organisation-commissioned review, which identified a lack of data on immunity beyond two years of age following reduced-dose pneumococcal vaccination schedules.

Researchers caution that the findings apply specifically to PCV13 in settings with established, high-coverage vaccination programmes and that additional research is needed among HIV-exposed and HIV-infected populations, as well as for newer pneumococcal vaccine formulations.