The Perfect Enemy | Covid News and Updates: Vaccines for Children and More
March 12, 2024
Meridith Kohut for The New York Times

The Food and Drug Administration authorized on Friday both the Moderna and Pfizer-BioNTech coronavirus vaccines for the nation’s youngest children, a relief to many parents anxious to protect their children 18 months after shots were first made available to adults.

Regulators followed the recommendation of independent experts on an advisory panel, who voted unanimously on Wednesday in favor of both vaccines. All Americans other than the roughly 20 million children under the age of 5 have had the option of protecting themselves against Covid-19 for months and are eligible for booster shots.

Moderna’s two-dose vaccine is for children 6 months through 5 years old, while Pfizer’s three-dose vaccine is for children 6 months through 4 years old.

A separate advisory panel to the Centers for Disease Control and Prevention is meeting Friday and Saturday on the matter. Afterward, the C.D.C.’s director, Rochelle P. Walensky, will issue her own recommendation, the final step before doses are rolled out, probably early next week.

Uptake could be low, which would be particularly worrisome for children with underlying conditions that might make them more vulnerable to being hospitalized with the virus.

Both Pfizer’s and Moderna’s studies showed that the Omicron variant of the virus greatly dulled the power of the vaccines to prevent symptomatic infection in young children, just as it did for adults.

Pfizer has said that two doses of its vaccine were only about 28 percent effective in preventing disease, while three doses were 80 percent effective. But that 80 percent estimate was based on only 10 cases in a subset of 1,678 trial participants.

Moderna’s vaccine was about 51 percent effective in children 6 months to 2 years old and 37 percent effective in children 2 through 5.

Still, Dr. Robert M. Califf, the F.D.A.’s commissioner, said in a statement, “As we have seen with older age groups, we expect that the vaccines for younger children will provide protection from the most severe outcomes of Covid-19, such as hospitalization and death.”

Both vaccines provoked an immune response comparable to that triggered in young adults, the primary criteria by which the agency measured effectiveness. Asked to compare them at a press briefing, Dr. Peter Marks, who heads the F.D.A.’s vaccine division, said that Moderna’s vaccine might trigger the immune response “slightly more rapidly,” while Pfizer’s might “bring a greater response after the third dose.”

But he said parents should feel comfortable with either, and he recommended they go with whichever one is available.

After the federal government made 10 million doses available to states, pharmacies and health providers in recent weeks, the response was muted, according to data collected by federal officials. Just 2.5 million doses of Pfizer-BioNTech’s vaccine have been claimed, around half of what was available. And about 1.3 million Moderna doses, about a quarter of what was offered, had been ordered.

Cori J. Darr, of Riverside, Mo., said early Friday morning that she would seek the vaccine immediately for her daughter, who will turn 5 in November. “I was starting to think that she would age into a vaccine before anyone bothered to approve one,” she wrote in an email.

But she said so far she is having trouble figuring out where to go. She said neither her pediatrician’s office nor her local health department plans to offer the shot, and the vaccine clinic at her local children’s hospital has closed.

Federal officials have said that states typically gradually increase orders as vaccination campaigns evolve. But less than 40 percent of children ages 5 to 11 have received at least one dose of a coronavirus vaccine, a sign that families, including those whose adult members were eagerly vaccinated, might be hesitant to inoculate their children, at least right away.

Pfizer’s vaccine regimen is three doses at one-tenth the strength of its adult dose. The first two doses are three weeks apart; the third dose is at least two months after the second. That means it would take three months to be fully vaccinated.

Moderna’s vaccine is two doses, four weeks apart at one-fourth the strength of its adult dose. Its dose is significantly stronger dose than Pfizer’s and the time frame is shorter, which might appeal to parents eager for children to finish the series.

The F.D.A. has said both vaccines might need boosters. That would mean that Pfizer-BioNTech’s vaccine would be four doses and Moderna’s would be three.

Dr. Erin Rose Medina, of Spokane, Wash., said she prefers Moderna for her three-year-old son because she thinks the data suggests it may be more effective. “Another reason to go with Moderna — faster to get to fully vaccinated status,” she wrote in an email. But she added: “If only Pfizer is available we won’t wait for Moderna.”

Some pediatric and vaccine experts have said that it is extremely hard to try to compare the two vaccines, in particular on the question of which is more effective.

“I don’t think there is convincing enough data to say one is better than the other,” said Dr. Kristin Moffitt, a physician at Boston Children’s Hospital who has treated young Covid-19 patients. “We all need to acknowledge that to compare the two head-to-head is very tricky, given that they were studied differently.”

Dr. James Conway, a pediatric infectious disease expert at the University of Wisconsin-Madison. said it was hard to pinpoint how much protection either vaccine might provide given that newer, more contagious versions of the virus are now circulating. “You’re kind of playing Whac-a-Mole,” he said.

Pfizer’s efficacy estimate, Dr. Moffitt said, was particularly unreliable because there were so few cases of the virus among trial participants after the third dose. “We’re going to need to wait and be patient to understand the true effectiveness of each of these vaccines.”

Still, given that Pfizer-BioNTech’s vaccine has been authorized for children 5 and older for many months, Dr. Moffitt said some parents might feel more comfortable with that vaccine.

Some pediatricians, nurses and pharmacists might be more familiar with that vaccine and not want to introduce another product.

Until Friday morning, Moderna’s vaccine was restricted to adults. The F.D.A. authorized it for children and teens 6 through 17 as well as for the younger children.

Emily Erdos contributed reporting.