Should an 11-Year-Old Wait to Get the Bigger Covid-19 Vaccine Dose?

When Rachel Adams-Kaplan heard that the Covid-19 vaccines would soon be available for her children, she knew she would get her 7-year-old son vaccinated right away. She wasn’t so sure about her 11-year-old daughter.

Children between 5 and 11 years of age began getting Covid-19 shots last week, after the Centers for Disease Control and Prevention recommended Pfizer Inc. PFE -0.82% and BioNTech SE’s BNTX -1.32% vaccine for that age group. Some 900,000 children in that age group had received a first dose through Wednesday, White House Covid-19 coordinator Jeff Zients said.

The vaccine will be given in two shots, spaced three weeks apart, as with adults. But the amount per dose for younger children and people 12 and older differs significantly. People who are between the ages of 5 and 11 will get 10 micrograms of the vaccine per dose, while those 12 and older will get 30 micrograms—three times as much.

Ms. Adams-Kaplan, a kindergarten teacher in Philadelphia, said she thought about waiting to get her daughter the larger, 30-microgram dose after she turns 12 on Nov. 26, thinking it might better protect her against Covid-19.