Vaccines could get authorized for young kids this fall. Here are the drug companies’ most likely timelines.

Children covid-19 vaccine
Monserat Ramos, 3, kept a close eye on the needle as her grandparents got vaccinated in Los Angeles on March 5. Francine Orr /Los Angeles Times via Getty Images
  • Coronavirus vaccines won’t be available for children under 12 until fall at the earliest.
  • Pfizer expects to know how its vaccine performs among kids ages 5 to 11 by the end of September.
  • Moderna could produce data for that same age group in late fall or early winter.
  • See more stories on Insider’s business page.

It’s one of the US’s biggest hurdles to getting the population vaccinated: Children under 12 – nearly 15% of the country, or around 48 million Americans – aren’t yet eligible to receive coronavirus shots.

Both Pfizer and Moderna entered young kids into their clinical trials in March, but the results of those studies haven’t been published.

Pfizer expects to have data about its vaccine’s efficacy among kids ages 5 to 11 by the end of September. It usually takes the Food and Drug Administration a few weeks to review such data, so that would put the US on track to start administering shots to young kids in October at the earliest, assuming the trial results are good.

Data for the other age group Pfizer is studying, children ages 6 months to 5 years, could be available shortly thereafter, Pfizer said in July. The company previously estimated that results for its youngest age group could be available by October or November.

Moderna, meanwhile, expects to have data about its vaccine’s efficacy among young kids in late fall or early winter.

Federal health authorities and Wall Street analysts have offered slightly different timelines

Fauci
White House Chief Medical Advisor Anthony Fauci. Pool / Pool/ Getty Images

Former FDA Commissioner Scott Gottlieb, who sits on Pfizer’s board, told CNBC on Monday that the FDA could greenlight Pfizer’s shot for kids under 12 in late fall or early winter.

But he added that Pfizer’s emergency-use application “probably isn’t going to be submitted until some point in October.” From there, he estimated, the FDA might take four to six weeks to review the data.

White House Chief Medical Advisor Anthony Fauci told NBC’s “TODAY” last week that “there’s a reasonable chance” that younger kids could be vaccinated by the winter holidays.

But Wall Street analysts have a slightly more optimistic timeline.

In a Tuesday report, Morgan Stanley analysts said they expected Pfizer to submit an emergency authorization for kids ages 5 to 11 in September, putting the US on track to vaccinate this age group in the fall. The analysts estimated that Pfizer would produce data for kids ages 6 months and up in November, meaning the youngest kids could get vaccinated in late 2021 or early 2022.

Moderna, they said, could produce data for kids ages 6 to 12 in the fall, around one to two months after Pfizer. Data for kids 6 months and up would then be available in late 2021 or early 2022, they added, meaning Pfizer could file for emergency authorization for its youngest age group next year.

The FDA hasn’t yet authorized Moderna’s and J&J’s shots for older kids

Kid pfizer vaccine
Malikai McPherson, 16, received Pfizer’s vaccine at a clinic in Melbourne, Florida, on May 17. Paul Hennessy/SOPA Images/LightRocket/Getty Images

The FDA asked both Pfizer and Moderna to expand their under-12 trials in July, citing concerns that the studies weren’t large enough to detect rare side effects such as heart inflammation.

Until then, Pfizer had been studying its vaccine in up to 4,500 young children, divided among two age groups: 5 years to 11 years and 6 months to 5 years. Moderna’s trial, meanwhile, included three age groups – 6 years to 11 years, 2 years to 5 years, and 6 months to less than 2 years – each with 2,265 participants. The FDA asked both companies to include at least 3,000 children in the 5-to-11 age group, The New York Times reported.

The FDA authorized Pfizer’s shot for children ages 12 to 15 in May. But Moderna is still waiting on the agency to authorize its shot for kids from 12 to 17, after seeking emergency authorization in June. The FDA could greenlight that shot for this age group any day now.

Johnson & Johnson is on a slower timeline. The company won’t start studying its vaccine among children ages 12 to 17 until this fall. If the shot is shown to be safe and effective among older kids, J&J could then start enrolling 2- to 11-year-olds, followed by children younger than 2.

That means a single-dose shot likely won’t be available to kids until sometime in 2022.

Young children may receive a lower dose

Israel kid vaccine
A boy received the Pfizer vaccine in the Israeli city of Holon, near Tel Aviv, on June 21. Jack Guez/AFP via Getty Images

Pfizer’s phase-one trial indicated that a lower dose of its vaccine – 10 micrograms, as opposed to the 30 given to adults – is safe among children ages 5 to 11. The trial administered an even smaller dosage, 3 micrograms, to children ages 6 months to 5 years, who seemed to tolerate it well.

Moderna is similarly comparing its standard dose (100 micrograms) with lower doses for all age groups. Children ages 2 to 12 in the trial are receiving either 50 or 100 micrograms, and kids between 6 months and 2 years are receiving either 25, 50, or 100.

A lower dose could help avoid unnecessary side effects. Adolescents in Pfizer’s trials seemed to develop side effects more frequently than adults, likely because kids’ immune systems rev up quickly. But even the most common side effects, such as fatigue and headaches, were relatively minor.

Since the FDA has fully approved Pfizer’s vaccine for people 16 and older, pediatricians can legally prescribe the shot for “off-label” use in young kids. But health officials have warned them not to do so yet.

“Keep in mind kids are not just scaled down adults,” Francis Collins, director of the National Institutes of Health, said on “Good Morning America” last week. “They have different immune systems and metabolism. You really have to do the careful trials to make sure you got the dose right and there aren’t any surprises.”