Stanford tests Pfizer shot on kids as young as two

As statewide eligibility for the COVID-19 vaccine expands to residents 16 and older in California, researchers at Stanford Medicine have set their sights on an even younger group: children ages two to five.

The medical school Wednesday began administering doses to children in the tender age group as part of a larger, threephase trial of Pfizer-BioNTech’s COVID-19 vaccine that will ultimately include children ages six months to 12 years.

“We want to protect children just as we want to protect adults from this disease,” said Dr. Yvonne Maldonado, the pediatric infectious diseases expert leading the trial at Stanford.

About 76 million Americans have been fully vaccinated against the coronavirus, according to the U.S. Centers for Disease Control and Prevention, but children remain unprotected even as they head back to school.

The first phase of the Pfizer study is geared toward finding a safe dosage for preschoolage children, while the second and third phases will include a study of efficacy, Maldonado said.

The trial will start by testing a 10-microgram dose of the vaccine, then progress to doses of 20 and 30 micrograms if it’s safe to do so, according to Pfizer.

For comparison, people 16 and older receive two 30-microgram doses 21 days apart.

“The goal is really to find the right dose for little kids and make sure they tolerate the dose, don’t develop high fevers or any adverse events from these vaccines,” Maldonado said.

The study will include 144 volunteers in phase one, and up to 4,500 in phases two and three, according to Pfizer.