Public Health

FDA authorizes Pfizer’s Covid omicron booster as fourth shot for kids under 5

A staff member draws up a syringe with the Comirnaty vaccine from Biontech and Pfizer adapted to the Omicron-BA.1 variant at the Mainz vaccination center.

Sebastian Christoph Gollnow dpa | Picture Alliance | Getty Images

The US Food and Drug Administration authorized on Tuesday Pfizer’s omicron booster shot for kids under five years old who were previously vaccinated with three doses of the company’s original vaccine.

Children six months through four years old who completed their three-dose primary series with Pfizer and BioNTech’s original monovalent shots more than two months ago are now eligible to receive a single booster dose of the updated shot. The new shot is bivalent, meaning it targets the original Covid strain as well as omicron BA.4 and BA.5.

Pfizer’s primary series for young children consists of three doses, while rival drugmaker Moderna’s primary series for that same age group is only two.

Since December, children in that age group who completed two doses of Pfizer’s original vaccine have been eligible to receive the omicron booster as their third shot, or last dose in their primary series. The agency noted that children who received the omicron shot as their third dose aren’t eligible for the bivalent booster right now, but they should still be protected against a severe case of Covid.

The new authorization is for young children who completed their three doses before the new shot was available.

“Today’s authorization provides parents and caregivers of children 6 months through 4 years of age who received the three-dose primary series with the monovalent Pfizer-BioNTech COVID-19 Vaccine an opportunity to update their children’s protection by receiving a booster dose with the Pfizer- BioNTech COVID-19 Vaccine, Bivalent,” Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, said in a statement.

The agency’s decision aims to better protect young children after a gruesome winter season that saw hospitals overwhelmed with tots suffering from a variety of respiratory sicknesses, including Covid, RSV and the flu.

The FDA said the decision was partly based on clinical trial data from 60 children in the age group who previously received three doses of Pfizer’s original vaccine and were given one dose of the company’s new booster. One month after the children received the omicron booster, they demonstrated an immune response to both the original Covid strain and omicron BA.5 and BA.5

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