The Pfizer/BioNTech COVID-19 vaccine showed 90.7% efficacy against the coronavirus in a clinical trial of children 5 to 11 years old, the U.S. drugmaker said on Friday.
Sixteen children in the trial who had received a placebo got COVID-19, compared with 3 who were vaccinated, Pfizer said in briefing documents submitted to the U.S. Food and Drug Administration.
Because more than twice as many children in the 2,268-participant trial were given the vaccine than placebo, that equates to better than 90% efficacy.
Pfizer's clinical trial in those 5 to 11 years old was not primarily designed to measure efficacy against the virus. Instead, it compared the amount of neutralizing antibodies induced by the vaccine in the children to the response of older recipients in their adult trial.