Pfizer Inc said on Tuesday it will begin testing its Covid-19 vaccine in a larger group of children under age 12 after selecting a lower dose of the shot in an earlier stage of the trial.<br /><br />The study will enroll up to 4,500 children at more than 90 clinical sites in the United States, Finland, Poland and Spain, the company said.<br /><br />Based on safety, tolerability and the immune response generated by 144 children in a phase I study of the two-dose shot, Pfizer said it will test a dose of 10 micrograms in children between 5 and 11 years of age, and 3 micrograms for the age group of 6 months to 5.
