More than 28 million children across the US may soon be eligible to receive Covid-19 vaccinations, a step that could relieve anxiety for families, bring more kids back to schools, and slow the spread of the disease.
The Food and Drug Administration last week authorized the two-dose Covid-19 vaccine from Pfizer/BioNTech for emergency use in children between the ages of 5 and 11. The agency concluded that the benefits of the vaccine outweigh the risks in young kids, following the findings of an advisory committee. Now advisers to the Centers for Disease Control and Prevention are meeting this week to discuss guidelines for how the shots should be administered.
Immunizing young children against Covid-19 would make it more difficult for the coronavirus to spread and protect kids from falling ill. It’s big news for parents and kids, in part because the vaccine could ease the return to in-person schooling. “Vaccinating younger children against Covid-19 will bring us closer to returning to a sense of normalcy,” said acting FDA Commissioner Janet Woodcock, in a statement.
The Pfizer/BioNTech vaccine currently has full FDA approval for people ages 16 and older and a separate emergency use authorization for adolescents between 12 and 16. The emergency-use designation allows health workers to administer new vaccines during a public health emergency based on data from clinical trials. Full approval requires more clinical data and allows manufacturers to market vaccines and continue selling them after the public health emergency ends.
While children are generally at much lower risk of severe illness from Covid-19 than older adults, at least 690 children from birth to the age of 18 have died from the disease in the US so far. About 8,300 5- to 11-year-olds have been hospitalized for Covid-19, and at least 146 have died. Vaccines will drastically lower the chances of that happening, while also whittling down the risk that children will pass on the virus to others.
Although vaccines are the most effective tool for containing Covid-19, the experiences of older adults show that they’re not always enough. Infections after vaccination, known as breakthrough infections, are usually mild, but they have sickened and killed some people. The protection offered by vaccines can also wane over time. Changes in the virus itself have created variants like delta, which spreads more readily and can evade immune protection. That’s why health officials have recommended that vaccinated people continue to wear masks and maintain social distance in high-risk situations, like crowded indoor environments.
It’s not clear yet how much longer such measures will remain in place in schools, but as more kids get their shots, the odds rise that students can go to class without masks.
In the early days of the pandemic, doctors reported that adults were most vulnerable to severe illness from Covid-19, particularly older adults and those with preexisting health conditions like high blood pressure and other heart conditions. That trend has continued, and unvaccinated adults continue to experience the largest number of hospitalizations and deaths from the disease.
By contrast, children appeared to be at far lower risk of contracting the disease and seemed to have less severe outcomes, so young people became a lower priority for vaccinations than adults. However, as the vaccines rolled out and more adults gained immune protection, the relatively small number of infections in children started making up a larger proportion of Covid-19 cases.
“The focus was to get a vaccine for adults first,” said Kawsar Talaat, an associate professor at the Johns Hopkins Bloomberg School of Public Health, who led a Pfizer/BioNTech vaccine trial in children. “Once the trial in adults was finished, then it started going down in age.”
The initial clinical trials for the Pfizer/BioNTech vaccine, also known by the brand name Comirnaty, included participants aged 16 and up. Then the companies conducted further trials with the same vaccine formulation in kids as young as 12, which led experimenters to reconsider what dose of the vaccine was needed in young children.
“The incredibly robust immune response in the 12 to 15-year-olds made them think that maybe they didn’t need that high of a dose,” Talaat said. “There was a new study that started to look at the vaccine specifically in kids under 12, and we decided to test different doses.”
Researchers repeated the clinical trials in 5- to 11-year-olds, but with about one-third of the dose of vaccine that’s used in adults. The lower dose aims to minimize side effects and account for the fact that young children are both physically smaller and tend to have more robust immune systems than adults.
“Kids are not just little adults,” said Jennifer Nayak, an associate professor of pediatrics at the University of Rochester Medical Center. “Their size is different, but their immune systems are also different.”
Children who received the low-dose Pfizer/BioNTech Covid-19 vaccine, 10 micrograms, experienced an immune response comparable to adults who got the higher dose, according to the Pfizer/BioNTech trial. After the second injection, the trial showed, the vaccine was 90.7 percent effective at preventing symptomatic cases of Covid-19.
The trials, however, included just 4,600 children, compared to the trial in adults that included 44,000 participants. The pool of children in the trial was smaller because the Pfizer/BioNTech vaccine has already been administered to hundreds of millions of people around the world with a strong safety record.
However, some complications did emerge. For instance, the Pfizer/BioNTech vaccine is not recommended for people who are severely allergic to any vaccine ingredient, or who had an allergic reaction to the first dose. Researchers have also found that some recipients of mRNA vaccines, like the one from Pfizer/BioNTech, may be linked to rare cases of myocarditis, an inflammation of the heart muscle.
The trials in children showed no serious side effects, but some reported symptoms like pain at the injection site, redness, swelling, chills, and fever, with more side effects reported after the second dose.
While the wait for Covid-19 vaccines for 5- to 11-year-olds has been agonizing for kids and adults alike, this is still a record-breaking pace for vaccine approval. The previous record for a pediatric vaccine was held by the mumps shot, which took four years to develop.
Only 18 months have passed since the World Health Organization declared the start of the Covid-19 pandemic, and 11 months have passed since the FDA granted its first emergency use authorization for a Covid-19 vaccine.
It’s clear that children have suffered greatly from the Covid-19 pandemic. Beyond the kids who have been sickened and killed by the disease, millions more have lost caregivers and family members or struggled to keep up with their education as schools shifted to remote learning. The pandemic has also taken an enormous toll on mental health.
And though almost all children survive coronavirus infections, they can still infect others who are more vulnerable to some degree. That not only threatens to make other people sick, but also increases the chances that the virus will acquire dangerous mutations. So vaccinating children is likely important not just to protect them individually, but to limit the further spread of Covid-19.
Yet the current stage of the US epidemic is different from when Covid-19 vaccines began distribution to adults in December 2020. At that time, there were critical limitations on US supplies of the vaccine, so health officials debated exactly who should be at the front of the line.
Now, the US has stockpiled lots of Covid-19 vaccines, and some adults have become eligible for booster doses. Young children do remain at a lower risk of severe Covid-19 than adults, so health officials will likely recommend that children receive their first injections at doctor’s offices rather than mass-vaccination sites.
“The rollout initially is going to be much more through pediatricians,” said Nayak. “Initially, it’s going to be a conversation with a pediatrician, a discussion about risks and benefits, and hopefully a lot of parents will choose to have their children vaccinated.”
Now that the FDA has approved the pediatric Pfizer/BioNTech vaccine on an emergency basis, the CDC’s vaccine advisory committee will come up with recommendations for how to distribute the vaccine to kids. Nayak said the agency is likely to issue a blanket recommendation for 5- to 11-year-olds to get vaccinated.
One concern, however, is that families will decide whether to vaccinate their children, likely along the same fault lines that have defined Covid-19 vaccinations for adults. Age, income, ethnicity, and political beliefs are key variables shaping whether Americans get vaccinated, and some families seem especially hesitant about vaccinating young kids. (Having only an emergency-use vaccine authorization for young kids may contribute to hesitancy, despite safety data backing it.) School districts around the US will also come to different conclusions about whether to mandate, encourage, or remain indifferent about children getting their shots.
“I imagine there is going to be a huge amount of geographic variability on this,” said Nayak.
So far, vaccination rates are highest in older people and lowest in younger people, and if the pattern holds, it’s likely that 5- to 11-year-old children will have some of the lowest rates of vaccine uptake. Getting those numbers up will take time.
Another hurdle is that not every child has good access to medical professionals and can easily get to a doctor to receive a shot. Misinformation about Covid-19 vaccines, like the myth that they cause reproductive harm, could interfere with the rollout as well, according to Nayak.
Still, the more people who are vaccinated against Covid-19, the harder it is for the virus to spread. As more children head back to schools in person and more people gather indoors, having 5- to 11-year-olds vaccinated could blunt another winter spike in infections across the whole population. “We’re seeing that in places with high vaccination rates, transmission is lower than in places with low vaccination rates,” Talaat said. “I’m really excited about vaccinating my 10-year-old.”
Researchers are still planning to keep an eye on the children who participated in clinical trials for more than two years, to keep track of their level of protection and to monitor for any potential long-term complications. Some fraction of vaccinated children are also likely to experience breakthrough infections, and over time, protection from the vaccine may wane.
There are also Covid-19 vaccine clinical trials underway in children as young as 6 months old, so even more kids in the future may be eligible to get these shots. But again, even if they gain approval, the vaccines will only make a big difference if kids actually get them.