Pfizer Inc. said Thursday it has started testing its Covid-19 vaccine in young children, a key step toward broadening vaccination efforts.
Researchers administered the first doses of the vaccine to children enrolled in the study, which is evaluating the shots in children six months to 11 years. Pfizer expects initial results by the end of the year.
The vaccine, which Pfizer developed with BioNTech SE , is authorized for use in people 16 years and older. Pfizer had earlier started testing the vaccine in children ages 12 years to 15 years.
Children appear to be at lower risk of contracting the coronavirus than adults. When they are infected, they tend to experience milder symptoms, though some get seriously ill and can spread the virus.
Children make up about 13% of Covid-19 cases in the U.S., according to the American Academy of Pediatrics.
