Pfizer launches late-stage trial of Covid shot in kids under 12

Pfizer Inc. and BioNTech SE’s Covid-19 vaccine will be tested in children under the age of 12 in a late-stage study of as many as 4,500 participants.

The vaccine partners announced plans on Tuesday to kick-start the trial of the shot within weeks. It will be conducted at more than 90 sites, spanning the U.S., Finland, Poland and Spain. Based on findings from an early-stage trial that evaluated safety, tolerability and the immune response prompted by the vaccine, the companies selected new doses for children. Those ages 5 to 11 will receive a 10-microgram dose -- a third of the size given to those 12 years old and older. Children 6 months to 5 years old will be given 3 micrograms -- a tenth of the amount given to adolescents and adults.