Health · June 17, 2022

CDC advisors discuss vaccines for the youngest children

In deliberations on whether to recommend Covid vaccines for young children on Friday, scientific advisers from the Centers for Disease Control and Evaluation struggled with the complexities of evaluating two very different vaccines and with limited data.

The consultants are tasked with making recommendations for the use of the Moderna vaccine in children aged 6 months to 5 years and the Pfizer-BioNTech vaccine in children aged 6 months to 4 years.

Both vaccines appear to be safe for children, and committee members had few concerns about side effects. But the advisors ended the first day of their meeting with pointed questions to Pfizer about the effectiveness of its vaccine and the number of doses it requires.

The two vaccines differ in almost every aspect. For young children who receive the Moderna vaccine, the Food and Drug Administration has approved two doses of 25 micrograms each, a quarter of the amount used for adults four weeks apart.

However, according to data presented on Friday, two doses of Pfizer’s vaccine – just three micrograms each, or a tenth the adult dose – were not enough to induce strong immunity to the virus in young children.

To be effective, the Pfizer-BioNTech vaccine must be given in three doses: the first two three weeks apart, and a third at least two months later.

Pfizer has reported that three doses of its vaccine are about 80 percent effective against symptomatic diseases. However, that estimate is based on infections in just three children vaccinated in the company’s studies, CDC committee members noted.

“In the interest of some kind of full transparency for parents, I think it’s appropriate to acknowledge the uncertainty involved,” said Dr. Matthew Daley, a senior investigator at Kaiser Permanente Colorado who leads the CDC’s Vaccine Working Group.

Assuming the advisors support the vaccines, CDC director Dr. Rochelle Walensky is expected to give her approval shortly. States have already acquired millions of cans and will be ready to offer shots to children as early as Tuesday.

Pfizer’s vaccine has been available since November for children ages 5 to 11, but less than 30 percent of them have had two shots.

On Friday, panelists also spent a lot of time figuring out how the Omicron variants have altered risks to children. They found that parents vaccinate their children against many other diseases with a comparable or even lower risk of death.

The data “should only debunk the myth that this infection is not life-threatening in this age group,” said Dr. Sarah Long, panelist and infectious disease expert at Drexel University College of Medicine.

Unvaccinated people aged 5 and older were 10 times more likely to die from Covid-19 than those who received at least two shots, said Dr. Daley. The numbers “provide real-world evidence that most deaths from Covid-19 are vaccine preventable,” he added.

The acceptance of the vaccines will depend in part on how clear the CDC’s recommendations are. FDA approval allows vaccines to be used, but physicians contact the CDC’s advisory committee for details on their use.

Some studies have shown that the vaccines might work better if the interval between doses is lengthened, and the CDC now says children as young as 12 and younger adults at low risk of Covid-19 might consider getting their second dose of the vaccine eight weeks after the first receive .

But the United States hasn’t collected the information needed to determine the ideal interval for young children, said Dr. Doran Fink, a senior FDA official, on Friday.