Headlines about safe and effective covid-19 vaccines seem simple, but the truth is that the trials tell us far less than we assume about who will benefit from a vaccine

By Graham Lawton
A volunteer in Moscow takes part in the trial for the Sputnik V vaccine
Natalia Kolesnikova/Afp Via Getty Images
IT IS the ultimate exit strategy from covid-19. A safe and effective vaccine is of “critical importance to world health”, the World Health Organization (WHO) has said.
Vaccine developers are working flat out to make good on that. Last week, the US pharmaceutical giant Pfizer and its German partner BioNTech announced positive-looking results from their ongoing phase III trial, the last stage of testing whether a potential vaccine is safe and effective. The interim results showed a headline success rate …