Parents won't be able to vaccinate healthy children 6 months to 5 years old if the FDA pulls Pfizer's COVID-19 vaccine authorization.

The landscape of COVID-19 vaccinations for children is shifting in the US. How will this affect the upcoming virus season?

Under Robert F. Kennedy Jr., federal officials may withdraw an endorsement for the vaccine in younger children.

The Food and Drug Administration could pull Pfizer's coronavirus vaccine emergency authorization for children under age 5.

Currently, children ages 5 to 11 are eligible for two pediatric doses of Pfizer's Covid-19 vaccine but are not yet eligible for a booster. Pfizer is testing a third dose in that age group now.

It's important to note, however, that Pfizer's vaccine requires two doses administered several weeks apart to reach 95% efficacy. So 100 million doses would vaccinate half the number of people.

Coronavirus infections are climbing again, marking another summer wave as children go back to school. But this uptick arrives with an added layer of uncertainty because it’s unclear when and which Americans can receive updated vaccines this fall.