Design: Randomised, open-label, multicentre phase 4 non-inferiority trial
Population: 1404 adults in China, half aged 60 or older
Primary outcome: Antibody response after co-administration vs separate administration
Effect: Non-inferior for COVID-19 and all pneumococcal serotypes; mild extra local reactions

A randomised, open-label phase 4 trial in China enrolled 1404 adults, half aged 60 or over. Groups received an inactivated COVID-19 vaccine with the 23-valent pneumococcal polysaccharide vaccine, then COVID-19 vaccine with a quadrivalent influenza vaccine four weeks later; or each vaccine on its own schedule. Published in Human Vaccines & Immunotherapeutics on 21 October 2026.

Antibody levels after co-administration were non-inferior for COVID-19 and for every pneumococcal serotype. Seroconversion was less consistent for COVID-19 after the second dose and for influenza A(H1N1). Local reactions were slightly more common but mild, and there were no vaccine-related serious adverse events.

Every extra visit is a chance for an older adult not to come back. Giving vaccines together in one visit is a practical way to raise coverage.

The COVID-19 vaccine used is not the one generally used in India, and the trial was open-label.

Offer influenza and pneumococcal vaccines at the same visit to eligible adults
Warn patients that a sore arm is slightly more likely with two vaccines at once
Use each chronic disease review as a prompt to check adult vaccination
Give the vaccines in different arms or at separate sites

Why it matters

One visit instead of several removes a common reason older adults miss vaccines.

The statistics, in plain English

Non-inferior means the antibody response with co-administration was not worse than separate doses by more than a pre-set margin. The less consistent results for some strains and age groups came from subgroup analyses, which are weaker.