The FDA is taking an unusual approach in reviewing Pfizer’s proposed COVID-19 vaccine for preschoolers and toddlers — one that has some health experts already questioning the process.
To expedite approval, the Food and Drug Administration asked Pfizer for a “rolling submission” as it seeks emergency use authorization of its vaccine for kids 6 months through 4 years old. Under that plan, the agency will review safety and effectiveness of two shots of the vaccine, though early data showed it wasn’t effective in 3- and 4-year-old children. Pfizer has not yet submitted trial data of an expected third dose for young children, so it’s unknown whether a third dose will be effective in the older group.
“We literally change the rules at the FDA to try to bring a failed vaccine product to 6-month-old to 4-year-olds,” Dr. Vinay Prasad, an associate professor of epidemiology and biostatistics at UC -San Francisco, said Wednesday on Twitter.
At a White House briefing on the pandemic response Wednesday, Surgeon General Dr. Vivek Murthy insisted that the federal review remains rigorous and essentially unchanged.
“The FDA will not cut any corners in their review process,” Murthy said. “They know that they are the gold standard that all of us rely on.”
In response to a question about what had changed in the data to warrant the FDA considering Pfizer’s vaccine for kids under 5 now, rather than after data on a third dose are in, Murthy said Wednesday that the current omicron surge and its impact on children changed the risk-benefit calculus.
“With many children in particular as well as adults being infected and in the hospital during the omicron surge, it turns out that has actually facilitated the collection of important clinical data, additional clinical data that we did not have in December,” Murthy said. “Whether that changes the risk-benefit profile is what the FDA will be assessing.”
The move to vaccinate preschoolers already was controversial, with some experts questioning the benefit for young children who face minimal risk from COVID-19. More kids under 5 drowned in 2018 than have died from the virus since the pandemic began two years ago.
The FDA has been buffeted with criticism through the pandemic, for taking too long to approve COVID-19 tests and pushing vaccine boosters for low-risk groups — two top FDA scientists resigned last fall, reportedly over White House booster pressure.
But the FDA also is under pressure to approve vaccines in younger kids, as many parents fear their tots will get infected at day care and spread the virus through their household, particularly as the highly contagious omicron variant continues to menace the country.
With some 23 million kids in the U.S. under age 5, including 2.4 million in California, it is a sizeable population for which the vaccines have been unavailable.
“A vaccine for children under 5 would mean we would have vaccines available for essentially all age groups in America,” Murthy said Wednesday, noting he has a 4-year-old daughter. “This would be a major milestone.”
A panel of outside experts who advise the FDA on vaccines will meet Feb. 15 to consider whether clinical trial data demonstrate Pfizer’s shots for preschoolers and toddlers is both safe and effective. The vaccine is to be given like those for older kids and adults, with two shots given three weeks apart. The dosage for kids under 5 is about a third the dose for kids 5-11, which is a third of that for teens and adults.
In December, Pfizer revealed a setback in its clinical trials: the shots produced an immune response in the toddlers 6 months to 2 years old, but not for the 3-and-4-year-olds. The company said it had begun evaluating a third shot of the same dose to be given two months after the second in that under-5 age group.
In Tuesday’s announcement, Pfizer said that in response to an FDA request, it will seek authorization for the first two of its planned three-dose vaccine series for kids under 5. The drug maker will provide additional data and seek expanded authorization for the third dose “in the coming months.”
That plan has raised concerns among some health experts that it would undermine confidence in the vaccines effectiveness and safety, at a time when vaccine uptake among kids is already underwhelming — only about a third of U.S. kids ages 5-11 have had at least one dose.
Norman Baylor, president of Biologics Consulting and a former top FDA vaccine official, told the health news website Stat on Wednesday that “if the vaccine in this age cohort is a three-dose vaccine, FDA should review the data from the three-dose series before authorizing the vaccine.”
Baylor also said that authorizing the vaccine for 3 to 4 year-olds, when effectiveness in this age group hasn’t been confirmed, is not “going to convince the majority of parents to vaccinate their children.”
Jason L. Schwartz, an associate professor of health policy at Yale University, tweeted Wednesday that he wants to “see the data before passing judgment,” but that “those downstream risks of this unprecedented process are real.”
“Hard to imagine FDA would push for this approach without pretty compelling evidence even for 2 doses,” Schwartz said.
Pfizer said its trials found “no safety concerns” from the vaccine in kids under 5. Still, a concern among critics like Prasad is that FDA authorization “is a mandate in blue locations” like politically liberal California.
Dr. Monica Gandhi, an infectious disease specialist also at UCSF, said she doesn’t think that will happen, but that parents will be divided in their interest in the vaccine for their kids. She said current guidance from the Centers for Disease and Prevention for quarantine and isolation of children under 5 at daycare is more stringent than any other age group, so having the vaccine available would help keep childcare centers open if they are asked to follow CDC guidance.
“The risk of severe disease in children younger than 5 from COVID is very low and many parents will choose not to vaccinate their children for that reason,” Gandhi said. “Other parents have been anxious that their young children do not yet have a vaccine available to them and are looking forward to having the Pfizer vaccine authorized.”