Pneumosil matched GSK's PCV10 on shared serotypes, and covered 6A and 19A better

Design

Secondary analysis of two randomised immunogenicity trials

Population

716 infants given PCV10-SII, PCV10-GSK or PCV13

Primary outcome

Serotype-specific seroinfection between primary series and booster

Effect

vs PCV13: serotype 14 RR 0.35 (0.22 to 0.57); 6B RR 2.91 (1.84 to 4.60)

A secondary analysis in Vaccine (August 2026) used serum from 716 infants in two randomised trials comparing Pneumosil — the 10-valent pneumococcal conjugate vaccine made by the Serum Institute of India (PCV10-SII) — with PCV13 and GSK's PCV10. 'Seroinfection' was defined as a rise in serotype-specific IgG between the primary series and the booster, taken as a marker of colonisation or infection.

Against GSK's PCV10, seroinfection risk was similar for shared serotypes, and lower for 6A and 19A, which only Pneumosil contains. Against PCV13, risk was 65% lower for serotype 14 (RR 0.35, 95% CI 0.22 to 0.57), but 2.27 times higher for 6A (1.40 to 3.68) and 2.91 times higher for 6B (1.84 to 4.60), and similar for the rest.

Seroinfection is an indirect marker, not carriage or disease measured directly. The comparison matters for programmes choosing between vaccines on price and local serotype distribution.

• Pneumosil is WHO-prequalified and protected comparably to GSK's PCV10 for shared serotypes
• It may offer better coverage where 6A and 19A cause much of the disease
• PCV13 performed better against 6A and 6B in this analysis
• Complete the schedule with whichever PCV is available — the differences are serotype-specific, not overall

Why it matters

It gives the first efficacy-type comparison for a low-cost, Indian-made PCV that many national programmes rely on.

Don't overread it

Seroinfection is an antibody marker of colonisation, not measured carriage or invasive disease.

The statistics, in plain English

A relative risk of 0.35 means 65% lower risk of seroinfection with serotype 14; RRs of 2.27 and 2.91 mean more than double the risk for 6A and 6B. Each serotype is a separate comparison, so the vaccines differ in pattern, not simply better or worse.

Read the rest in the app

You have read your two free briefings this month. The app carries all 27 specialties, every morning, free — and this finding is waiting in it.

Get Daily Doctor — free

Scan to keep reading on your phone. No account needed to start.