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Vaccine data for children under 5 coming ‘before the end of the year’

The vaccine timeline for young children looks a little more solid. This morning, Pfizer data submitted to the FDA showing that the COVID-19 vaccine is effective and safe for children ages 5 to 11. And this afternoon, the company’s CEO, Albert Bourla, said the study results for even younger children, ages 2 to 4, will be available in a few months’ time. “Before the end of the year,” he confirmed in an interview with Craig Melvin, the… Today news anchor and MSNBC anchor, at The Atlantic Festival. Filing to the FDA will follow soon after, Bourla said.

The wait for COVID-19 vaccines comes during an ongoing wave of cases among children. Vaccines take so long to reach children because the trials follow the classic strategy of age de-escalation. Manufacturers tested their injections first on adults, then teenagers and most recently children as young as 2 years old. Pfizer is also conducting a pediatric trial for the youngest children from six months to two years old. Bourla did not specify a timeline for this cohort, but expects results sometime after those of the 2- to 4-year-old group.

Once the results for each age cohort are collected, Pfizer will submit them to the FDA for review for safety and efficacy. The agency doesn’t follow a set timeline, but for context, emergency use of Pfizer’s vaccine took 21 days from submission to authorization for adults and 31 days for teens ages 12 to 15. If that priority holds, kids ages 5 to 11 will. probably be able to take pictures around Halloween and those 2 to 4 will be eligible early next year. (Don’t be surprised if those timelines stretch out, However.)

All eyes are on Pfizer’s vaccine as the pediatric trials are most advanced. Moderna and Johnson & Johnson, the other two companies whose COVID-19 vaccines are approved in the United States, have not yet released data from their trials in children under 12. (Like Pfizer’s trial, these also apply to children as young as six months.) The first injection available to children will almost certainly come from Pfizer.

The adult and pediatric trials of COVID-19 vaccines differ in a number of important ways. First of all, Pfizer is testing a smaller dose in children. For adults and teens, each injection of Pfizer’s two-dose regimen contained a dose of 30 micrograms. For children 11 years and younger, the dose was reduced to just 10 micrograms per shot, and then further reduced to 3 micrograms for children from 6 months to 2 years. Based on Pfizer’s announcements, the data the company has collected so far suggests that the smaller dose is indeed safe and elicits a strong immune response in the 5-to-11-year-old cohort; their antibody responses are similar to those of adults who received the higher dose.

Speaking of that immune response, scientists evaluate the vaccine’s efficacy in children somewhat indirectly — this is another way these studies differ in adults and children. The COVID-19 vaccine is already known to be effective in adults, so researchers are looking at antibody responses rather than counting the number of vaccinated versus unvaccinated people who get COVID-19, as they did in the original adult trial. Studying efficacy by waiting for enough children in a trial to get COVID-19 would take a much larger trial — and much more time to complete it. These studies that focus on antibody response are called “immunobridging” studies and are standard in the study of vaccines.

But even if young children can be vaccinated – and current polls show many parents are still hesitant – the coronavirus is unlikely to go away. This is why pharmaceutical companies including Merck, Roche and Pfizer are also racing to develop antivirals to treat patients with COVID-19. This week, Pfizer announced that it is studying an oral pill that could block the replication of the coronavirus. Trials are currently underway to see if the pill can reduce or prevent COVID-19, Bourla told Melvin, and the first results are expected before the end of the year. The world is entering a third year with the coronavirus, but this time with many more pharmaceutical defenses in its arsenal.