As adults at high risk for Covid-19 prepare to be immunized against the coronavirus, many parents want to know: When will my child receive the vaccine?
The short answer: not before the end of the summer.
Pfizer and Moderna have enrolled children aged 12 and over in clinical trials of their vaccines and hope to have results by summer. Depending on the performance of vaccines in this age group, companies may test them on younger children. The Food and Drug Administration usually takes a few weeks to review data from a clinical trial and authorize a vaccine.
Three other companies – Johnson & Johnson, Novavax and AstraZeneca – also plan to test their vaccines on children, but are lagging behind.
When researchers first test drugs or vaccines on adults, they typically descend into the age groups, noting any changes in effective dose and unexpected side effects.
“It would be quite unusual to start reaching children at an early stage,” said Dr. Emily Erbelding, an infectious disease physician at the National Institutes of Health who oversees testing of Covid-19 vaccines in special populations.
Some vaccines – those that protect against pneumococcal or meningococcal bacteria or rotavirus, for example – have been tested in children first because they prevent pediatric diseases. But it made sense for coronavirus vaccines to be tested and authorized for adults because the risk of serious illness and death from Covid-19 increases dramatically with age, said Paul Offit, professor at the University of Pennsylvania and a member of the FDA vaccine advisory panel. .
“We are trying to save lives, keep people out of the ICU, prevent them from dying,” said Offit. This means prioritizing vaccines for older people and those with underlying diseases.
People under the age of 21 account for about a quarter of the United States’ population, but account for less than 1 percent of deaths caused by Covid-19. Still, about 2 percent of children receiving Covid-19 need hospital care and at least 227 children have died of the disease in the United States.
“It is a significant disease in children, but not necessarily when compared to adults,” said Dr. Kristin Oliver, a pediatrician and vaccine specialist at Mount Sinai Hospital in New York.
Children will also need to be vaccinated in order for the United States to move closer to collective immunity – the long-promised goal in which the pandemic subsides until it stops because the virus runs out of people to infect.
Scientists estimate that 70 to 90 percent of the population may need to be immunized against the coronavirus to achieve collective immunity, especially with more contagious variants that are expected to circulate widely in the country.
“Not all adults can get the vaccine because there is some reluctance, or maybe there are even some vulnerable immune systems that just don’t respond,” said Dr. Erbelding. “I think we have to include children if we are to achieve collective immunity.”
It will also be important to immunize children from the racial and ethnic populations most affected by the pandemic, she added.
The clinical trials of Pfizer and Moderna in adults each involved about 50,000 participants. They had to be so big to show significant differences between the volunteers who received the vaccine and those who received the placebo. But, as it is rarer for children to become seriously ill with Covid-19, this type of study design in children would not be feasible, because it would require many more participants to show an effect.
Instead, companies will screen vaccinated children for signs of a strong immune response that would protect them from the coronavirus.
The Pfizer-BioNTech vaccine was authorized in December for anyone aged 16 and over. The company continued its test with younger volunteers, recruiting 2,259 teenagers from 12 to 15 years of age. Teenagers are almost twice as likely to be infected with the coronavirus as younger children, according to the Centers for Disease Control and Prevention.
The results of this test are expected to be available in the summer, said Keanna Ghazvini, a spokesman for Pfizer.
“Moving to less than 12 years of age will require a new study and potentially a modified formulation or dosing schedule,” said Ghazvini. These tests are likely to begin later in the year, but plans will be finalized after the company has data on older children, she added.
Moderna’s vaccine, which was also authorized in December, follows a similar path for pediatric testing. In December, the company began testing teenagers aged 12 to 17 and plans to enroll 3,000 volunteers in this age group. The company expects results “around mid-2021,” said Colleen Hussey, spokeswoman for Moderna.
Based on the results, Moderna plans to evaluate the vaccine later this year in children aged 6 months to 11 years.
Babies may have some antibodies when they are born to vaccinated or infected mothers, but this maternal protection is unlikely to last until the first year of age. And with their relatively weak immune system, babies can be particularly susceptible to infection if transmission in the community is high.
The tests will also assess the safety of the vaccine in children – and, hopefully, lessen parental fears. A third of adults in the United States said they did not plan to immunize their children against coronavirus, according to a recent survey conducted by Verywell Health.
Given the low risk of Covid-19 in children, some parents may be skeptical about the urgency of inoculating their children with a brand-new vaccine, said Offit. “For that reason, the vaccine would have to be kept to a very high safety standard,” he said.
More than 42 million people in the United States have been immunized so far, with few lasting side effects. And the FDA has established several systems to carefully monitor any serious reactions to the vaccine.
“They are really examining the data very, very closely,” said Oliver. “As a pediatrician and mother, I am very confident that these systems work.”
Once a vaccine for children is available, schools can reintroduce extracurricular activities that involve close contact, such as band practice, team sports and choir. But in the meantime, there is ample evidence that schools can reopen with other precautions in place, said Oliver.
“I don’t think we need to anticipate a vaccine to open schools in the fall,” she said. “We should be planning to open schools now.”
Dr. Oliver also asked parents to ensure that children are immunized against other illnesses. According to the CDC, orders for non-flu childhood vaccines through the Children’s Vaccine Program reduced approximately 10.3 million doses in total.
“Now is the time to really catch up on missed doses of these vaccines,” she said. “Measles, HPV, tetanus intensifiers, whooping cough enhancers – all of these are really important.”