Pfizer and BioNTech are expected to ask FDA for an emergency use authorization (EUA) of their Covid-19 vaccine for children ages 6 months to 5 years old, a move that comes as vaccination efforts for children have stalled throughout the country.

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Pfizer-BioNTech submit EUA application

Pfizer-BioNTech are expected to submit their EUA application on Tuesday for a two-dose vaccine regimen for children under 5.

In December, the companies announced that children between the ages of 6 months and 2 years who were given two doses of the Covid-19 vaccine at a tenth of the adult dosage saw a robust immune response, but the same response did not occur among children ages 2 to 4. As a result, Pfizer-BioNTech are evaluating how effective a third dose of the vaccine will be for this age group.

"By now they probably have more information on whether the two shots provided any protection at all," said Bob Wachter, chair of the University of California San Francisco Department of Medicine. "It seems likely the third shot will be necessary … but you can't get shot number three until you've [had] shots one and two."

One person familiar with the situation told the Washington Post that the EUA application is aimed at getting children two shots for now, with a third dose possible later.

"We know that two doses isn't enough, and we get that," the person said. "The idea is, let's go ahead and start the review of two doses. If the data holds up in the submission, you could start kids on their primary baseline months earlier than if you don't do anything until the third-dose data comes in."

Sources told the Post that the vaccine could be available by the end of February. However, former FDA Commissioner and Pfizer board member Scott Gottlieb said the vaccine could be available by early March.

"Previously, we had data showing that the childhood vaccine for 6 months to 4 years wasn't as protective against infection as the adult vaccine. That's the reason they pushed it out," Gottlieb said. "But now, if the goal of the vaccine is to get baseline immunity into the kids to prevent bad outcomes and you're really not using the vaccine as a tool to prevent infection in the first place, two doses could do that. I think that may be why federal health officials are rethinking this."

Vaccination effort for children stalls in the U.S.

The news comes as the effort to get children vaccinated in the United States has largely stalled, Kaiser Health News reports. According to CDC data, just 30.4% of children ages 5 to 11 have received at least one shot of a Covid-19 vaccine, and just 21.6% have received both doses.

Experts have cited a variety of reasons why fewer children are getting vaccinated, including the fact that children are less likely to be hospitalized with Covid-19 than adults.

"One of the problems we've had is this perception that kids aren't at risk for serious illness from this virus," said Yvonne Maldonado, chair of the American Academy of Pediatrics (AAP) Committee on Infectious Diseases.

AAP has said the omicron variant has intensified the threat of Covid-19 to children under 5, and that those children are facing "an especially challenging moment in this pandemic."

"Sadly, we are seeing the rates of hospitalizations increasing for children 0 to 4, children who are not yet currently eligible for Covid-19 vaccination," CDC Director Rochelle Walensky said in January, adding that the high transmission rate of omicron was likely to blame.

Parents may be hesitant to vaccinate their younger children, even after a vaccine for children under 5 is authorized, as they have been with older children. A poll from the Kaiser Family Foundation found that 29% of parents of 5 to 11-year-olds said they definitely won't get their children vaccinated, and 7% said they'd only do so if they were required to.

"The key question is whether the parents of younger children will get their kids vaccinated," said Celine Gounder, a clinical assistant professor at NYU Langone Health. "Parents are relatively more hesitant to get their young children vaccinated than themselves." (McGinley et al., Washington Post, 1/31; LaFraniere/Weiland, New York Times, 2/1; Granitz/Stein, NPR, 2/1; Owens, Axios, 1/31; Reed, Axios, 1/31; Choi, The Hill, 1/31; Pradhan/Recht, Kaiser Health News, 1/14)