Pfizer lowers COVID-19 vaccine dose for younger kids in next stage of trial

Pfizer said Tuesday it has begun testing its COVID-19 vaccine in a larger group of younger children and has selected lower dosages of the shot compared to the volume given to those 12 and older.

"Although data shows that severe #COVID19 is rare in children, widespread vaccination is a critical tool to help stop transmission. That’s why I’m excited we have begun dosing participants aged 5 to 11 in a global Phase 2/3 study of the Pfizer-BioNTech #COVID19 vaccine," PFizer CEO Albert Bourla said in a statement on Twitter.

Pfizer enrolled 144 children in the first phase of the trial. The next phase of the study aims to enroll up to 4,500 children at more than 90 clinical sites in the U.S., Finland, Poland and Spain, the company said.

Children ages 5 to 11 will receive a 10 microgram dose level, while those under 5 and down to 6 months will receive a 3 microgram dose level. The shots will continue to be given on a two-dose schedule spaced 21 days apart. 

The U.S. Food and Drug Administration has given an emergency use authorization to Pfizer’s COVID-19 vaccine in individuals 12 and older. Everyone in this group receives two-30 microgram doses, also spaced three weeks apart.

FILE - A boy receives a first dose of the Pfizer COVID-19 vaccine in the Real Mutua Vaccination Hub on June 5, 2021 in Turin, Italy. (Photo by Diego Puletto/Getty Images)

"The Phase 1 study was conducted precisely to understand the best safety and tolerability profile for each age group of those between the ages of 6 months to 11 years," a Pfizer spokesperson said. "We took a stepwise, measured approach to evaluate all doses and decided to move forward with these two doses considering their tolerability profile for each group."

More than 6 million adolescents have received at least one dose of the Pfizer shot in the U.S., data from the Centers for Disease Control and Prevention shows.

This story was reported from Cincinnati.