Amid pathetic adoption, FDA green lights confuse COVID vaccine update for children

Enlarge / Reisa Lancaster RN, left, administers the Covid-19 vaccine to 14-month-old Ada Hedge, center, comforted by mom Sarah Close and dad Chinmay Hedge, just at the Children's National Research and Innovation Campus, in Washington, DC . Getty | The Washington Post, Bill O'Leary

The Food and Drug Administration has updated COVID-19 vaccine doses for children under 5, but changing authorized vaccination schedules is far from straightforward. This could further cripple vaccination efforts for younger Americans, who are already off to a disastrous start.

After months of availability, only about 3% of infants and toddlers ages 6 months to 2 years have completed a primary series. According to data from the Centers for Disease Control and Prevention, only 6.5% have received at least one vaccine. For children aged 2-4 years, just under 5% completed a primary series, with 9% receiving at least one dose.

It was June when the FDA cleared (and the CDC approved) small doses of Moderna and Pfizer's COVID-19 vaccines for children as young as 6 months old.

For Moderna's vaccine, infants 6 months to 17-year-olds could receive a primary series of two doses, one month apart. For Pfizer's vaccine, infants 6 months to children up to 4 years could receive a primary series of three doses, with the second given three weeks after the first and the third given at least eight weeks after the second. (Pfizer's vaccine was previously available for children 5 years and older.)

This fall, the FDA cleared an "updated" bivalent vaccine for use as a booster dose in people ages 5 and older. The bivalent shot targets both the original version of SARS-CoV-2 and the BA.4/5 subvariants of the omicron coronavirus, which dominated during the summer months. Now, the genetic offshoots of BA.5 dominate circulation. Recent real-world efficacy data suggests that bivalent booster provides up to 56% more protection against symptomatic COVID-19 infection than protection against original boosters.

But until now, children under 5 only had the original primary series, not boosters or bivalent injections.

What's new for young children

On Thursday, the FDA cleared bivalent injections for children 6 months to 4 years old and the CDC is expected to approve the clearance soon, opening up availability. But permissions are a bit complicated; this is not a blanket clearance for boosters in this age group.

Only children aged 6 months to 5 years who received the primary two-dose series of Moderna are eligible to receive a single bivalent vaccine as a booster dose. This booster dose should be given at least two months after the end of the primary series.

For Pfizer's bivalent vaccine, there is still no booster available for children under 5 years old.

The FDA has updated Pfizer's three-dose primary series to include the bivalent vaccine as the third injection in the series. This means that any child aged 6 months to 4 years who has not been vaccinated and is starting a Pfizer series or who has already started a Pfizer three-dose series but has not yet completed it can receive the bivalent dose as third dose in Pfizer's three-dose primary series. For example, if a 2-year-old child has already received two doses of Pfizer and is...