[Originally published: March 31, 2021. Updated: April 9, 2021]
On Friday, April 9, Pfizer submitted a request to the Food and Drug Administration (FDA) to expand the use of its COVID-19 vaccine to adolescents ages 12 to 15. This came after the company released preliminary clinical trial results a week earlier.
Those results, showing that the Pfizer-BioNTech COVID-19 vaccine is highly effective in kids ages 12 to 15, came as no surprise to Onyema Ogbuagu, MBBCh, a Yale Medicine infectious diseases specialist, who has led Yale's COVID-19 vaccine trials.
Dr. Ogbuagu was a principal investigator in the Phase 3 study on adolescents completed at Yale, and he is now preparing to study the vaccine in children 6 months to age 11. In late March, the drug makers announced, through a press release, that the vaccine demonstrated "100% efficacy and robust antibody responses," higher than those recorded earlier in ages 16 to 25. Side effects were also similar to those in that age group.
The consistency of strong results is notable. “Each study validates the other and seeing the adult data, which looked so incredible initially, and now seeing these same excellent results is very reassuring,” Dr. Ogbuagu says. “If this had been the first vaccine study, one eyebrow would have been up about the results and the fact that it was a small study. But viewed in the context of the adult data, and how effective the vaccines have been in studies and now in the real world—with data coming in from the U.S., Israel, and the U.K.—it puts these studies into context. It’s hard to not be impressed.”
Kids make up nearly 30% of the population. If we can vaccinate them with such a low margin of error, that puts us on an easier path toward herd immunity. Onyema Ogbuagu, MBBCh, Yale Medicine infectious diseases specialist
Among the 2,260 trials participants, there were no symptomatic COVID-19 cases in those who received the vaccine, compared to 18 symptomatic cases in the placebo group. The study enrolled participants in January and went on for about two months after vaccine completion, Dr. Ogbuagu says. The companies did not yet release detailed data from the trial and the results have not yet been peer-reviewed.
The request to the Food and Drug Administration (FDA) is an amendment to the vaccine’s existing emergency use authorization for adults. If granted, this could allow for vaccinations to begin for middle and high school students by the start of the next school year.
More work to do
While this news is good, the work is not done, Dr. Ogbuagu stresses. “There’s always a chance that, between now and when the FDA approves its use, there could be more cases,” he says.
The ability to vaccinate children, Dr. Ogbuagu notes, is a major milestone. “Kids make up nearly 30% of the population. If we can vaccinate them with such a low margin of error, that puts us on an easier path toward herd immunity,” he says. “This has huge implications for school reopenings and what kids can do in the future.”
Meanwhile, researchers are exploring how the vaccine works in this age group against asymptomatic cases, meaning among adolescents who are infected but don’t have symptoms.
And while very few children get seriously ill or die from COVID-19, Dr. Ogbuagu says, in this group there is also the risk of “long COVID,” in which even mild cases leave symptoms that can persist for a significant amount of time.
In future studies of younger children, Dr. Ogbuagu says smaller doses of the vaccine will be tested. In this study of adolescents, participants received the same amount of vaccine that is used for adults.
“We were happy to see that the safety profile was the same in kids as it was for adults. They did just fine, and their experience with side effects was no different than what we saw in the adult population,” he says.
Elsewhere in the U.S., a clinical trial of the Pfizer-BioNTech vaccine has begun in children ages 5 to 11. Moderna is also expected to release results from a trial in adolescents ages 12 to 17 soon.