Every day, more people are receiving their COVID-19 vaccinations, but one prominent group of Americans, children, still can't get the vaccine, though many experts agree they will need to in order for life to return to normal.
Though we may be one step closer: On Friday, Pfizer and BioNTech asked the Food and Drug Administration to amend the emergency use authorization of its COVID-19 vaccine to include kids between the ages of 12 and 15. The vaccine is currently authorized for people ages 16 and older.
In December, Moderna started its trial in kids between 12 and 17, and the company has since begun a study of the vaccine in children ages six months to 12 years old. Earlier this year, AstraZeneca, whose COVID-19 vaccine is not currently authorized in the U.S., announced plans to test its vaccine in kids as young as 6 in three U.K. cities.
Johnson & Johnson, which most recently received emergency use authorization for its single-dose COVID-19 vaccine, has begun vaccinating teens between 16 and 17 as part of ongoing clinical trials. Following the data from older teens, it will expand to kids 12 and up before progressing to children as young as newborns, the company said in its EUA application. It also plans to test the vaccine in pregnant women and their infants, and then immunocompromised people.
The timeline for when kids of all ages will have access to the COVID-19 vaccines is still in flux and will depend on when the data from these trials is released. Here's what we know now about what the trials might reveal and what this means for school in the fall.
What is the status of COVID-19 vaccine trials in kids?
Pfizer announced in late March that its vaccine was found to be safe and 100% effective in this 12 to 15 year olds and is currently seeking to amend its EUA to include that age group. (The findings have not been peer-reviewed.) The Pfizer shot is already cleared for use in people 16 and up and the company has also launched a clinical trial in kids 6 months to 11 years.
Moderna has fully enrolled its clinical trial in ages 12-17, and recently launched a study in children ages 6 months to 12 years old. Moderna president Dr. Stephen Hoge told TODAY in mid-March that he expects to have data from the study in older kids "hopefully" by the summer.
But Hoge cautioned that the study in babies to preteens could take "the better part of this year" to complete because "you do need to be a little more cautious and progressive in working down dose levels in the (younger) kids to find the right dose." The study in younger kids is being done in two parts, he added. The first part is about "finding the right safe and effective dose" in this age group, and the second part will be testing it in a large number of kids, about 7,000, he said.
Generally speaking, clinical trials in kids start with older age groups and progress downwards, with 5 to 2 year olds second to last, and 2 to 6 months last, Dr. Octavio Ramilo, chief of infectious diseases at Nationwide Children’s Hospital in Columbus, Ohio, previously told TODAY.
When looking at how trials in kids have progressed so far, Onyema Ogbuagu, a professor at Yale School of Medicine in New Haven, Connecticut, who led the university's Pfizer trials, said that it took about two to three months to have enough data on outcomes in older kids. Then, the FDA requires another two months of safety data after the second shot is administered. From there, the FDA will need at least another two to four weeks to review it before granting authorization.
Similarly, Dr. Robert Frenck, who worked on the Pfizer trials at Cincinnati Children's Hospital, estimated based on his experience that the expedited process for other kids trials could generate data as soon as three to four months after full enrollment. He stressed and assured concerned parents that no corners are being cut on assessing safety.
Is the COVID-19 vaccine safe in kids?
Ultimately, only the data, which isn't available yet, can answer this question, but so far, signs are good for the Pfizer vaccine, Frenck said.
"Anecdotally, my experience, is that ... the adverse events have basically been the same in the kids as ... adults," he explained. "I don't have all the data from all the (trial) sites to be able to flat out say, but I have not seen that the kids are getting any different of a safety response."
Based on research in adults, the CDC has said that COVID-19 vaccines are safe and effective. The most common side effects in adults include pain and swelling near the injection site, and fever, chills, tiredness and headache throughout the rest of the body.
The ongoing and future studies in children are primarily looking at two things, safety and tolerability, and immune response, noted Dr. Rick Malley, an infectious disease pediatrician at Boston Children's Hospital.
"Immune response tells you that you're not seeing something that is unexpected ... that they're actually responding the same way (as) adults," he said. This data is also not available yet.
Hoge also said that while Moderna's safety data in kids isn't available yet, researchers "haven’t seen anything concerning in our prior work that would suggest we can't use the vaccine in children."
When will most kids be vaccinated against COVID-19?
Again, this will depend on when the data from clinical trials becomes available, as well as other factors relating to vaccine distribution. Malley and Frenck both think it's likely that vaccines will be available to older children, 12 and up, first.
Frenck's "best guess," he said, is that this age group may be able to get vaccinated as soon as August and younger children in December 2021 to January 2022. NBC News medical contributor Dr. Natalie Azar predicted that vaccines will be available for kids over 12 years old before this fall.
Hoge said that he thinks the Moderna vaccine could be available to adolescents between 12 and 17 "going into the school year."
Malley provided a more conservative estimate. "I could envision, certainly for teenagers, so high school, middle school ... end of this year," he said. For younger kids, he suspected most vaccinations would occur in 2022. "We'll have to see how quickly these studies get done for younger children," he added.
"I think we do need to be careful because ... if we say fall, then (parents) start thinking, 'Well, I can vaccinate my kids before they go back to school,' and I don't know that that's going to be the case," Malley stressed.
Frenck estimated that the once vaccines become available to adolescents, it could take another several months for most kids to be vaccinated because, again, it will depend on the data from the younger trials. "Things may go quicker," he added. "COVID has kind of rewritten the books for doing clinical trials."
Another factor to consider in this timeline is how quickly more high-risk groups will be vaccinated, Ogbuagu explained. CDC data shows that most kids are less likely to get severely ill from COVID-19, but they can get sick and spread the virus.
"I can't imagine a scenario where kids would be the priority group for anyone," he said. "Even if the vaccine were available, I don't think you can just switch from the elderly that you haven't completed and people with underlying (conditions) to then vaccinate kids."
He added that even if the data from the Pfizer adolescent trials leads to an EUA as early as June, "the question is would the country be ready to ... offer it to kids? I don't know. ... There's just so many unknowns to make an exact prediction."
What does this mean for the fall 2021 school year?
In March month, the CDC released a roadmap for opening schools during the epidemic, stressing the need for masking, hand hygiene and social distancing, and monitoring levels of spread in the community. It did not state that children and school staff need to be vaccinated to return.
"The data suggests that where public health measures are instituted and adhered to in school settings, that even in areas where there's high community transmission, the schools haven't contributed much to that problem," Ogbuagu said. "So it almost seems like vaccination will be a plus, but it's not indispensable with regards to schools reopening safely."
Frenck added that he sees teachers being vaccinated as a "good justification for sending kids back to school. ... It's unusual that kids are acquiring the infection in the school setting."
But Malley cautioned that the COVID-19 variants spreading across the U.S. could change things.
"If ... schools become a greater center for spread from children to each other and children to adults, the urgency to try to prevent that, either through more distancing measures ... or, of course, vaccination becomes much more important."
This story was updated on April 9, 2021.