As adults at high risk for Covid-19 prepare to be immunized against the coronavirus, many parents want to know: When will my child get a vaccine?
The short answer: not until the end of summer.
Pfizer and Moderna have enrolled children 12 and older in clinical trials of their vaccines and hope to see results by the summer. Depending on the performance of vaccines in this age group, companies can then test them on younger children. The Food and Drug Administration typically takes a few weeks to review data from a clinical trial and approve a vaccine.
Three other companies – Johnson & Johnson, Novavax and AstraZeneca – also plan to test their vaccines in children, but are even further behind.
When researchers first test drugs or vaccines in adults, they typically move down the age brackets, watching for any effective dose changes and unexpected side effects.
“It would be quite unusual to start descending in 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 – were first tested in children because they prevent pediatric illnesses. But it made sense for coronavirus vaccines to be tested and licensed for adults first, as the risk of serious illness and death from Covid-19 increases sharply with age, said Paul Offit, professor at the University of Pennsylvania and FDA member. vaccine advisory committee.
“We are trying to save lives, to keep people out of the ICU, to keep them from dying,” said Dr Offit. This means prioritizing vaccines for older people and those with underlying illnesses.
People under the age of 21 make up about a quarter of the population of the United States, but they represent less than 1% of deaths from Covid-19. Yet about 2 percent of children with Covid-19 require hospital care, and at least 227 children in the United States have died from the disease.
“It’s an important disease in children, but not necessarily when compared to adults,” said Dr. Kristin Oliver, pediatrician and vaccine specialist at Mount Sinai Hospital in New York.
Children will also need to be vaccinated to bring the United States closer to herd immunity – the long-promised goal in which the pandemic slows and stops because the virus runs out of people to infect.
Scientists have estimated that 70 to 90% of the population may need to be immunized against the coronavirus to achieve herd immunity, especially with more contagious variants 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 aren’t responding,” Dr Erbelding said. “I think we have to include children if we are to get collective immunity.”
It will also be important to immunize children from the racial and ethnic populations hardest hit by the pandemic, she added.
The clinical trials of Pfizer and Moderna in adults each recruited approximately 50,000 participants. They had to be this large to show significant differences between the volunteers who received a vaccine and those who received a placebo. But since it is rarer for children to become seriously ill with Covid-19, this type of trial design in children would not be feasible, since it would take many more participants to show an effect.
Instead, companies will look in vaccinated children for signs of a strong immune response that would protect them from the coronavirus.
The Pfizer-BioNTech vaccine was approved in December for anyone 16 years of age and older. The company continued its trial with young volunteers, recruiting 2,259 adolescents aged 12 to 15. Teens are about 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 trial should be available by the summer, said Keanna Ghazvini, spokeswoman for Pfizer.
“Going below 12 years will require a new study and potentially a modified formulation or dosing schedule,” Ms. Ghazvini said. Those trials will likely begin later this year, but plans will be finalized after the company has data on older children, she added.
Moderna’s vaccine, which was also cleared in December, is on a similar path for pediatric testing. In December, the company began testing adolescents aged 12 to 17 and plans to enroll 3,000 volunteers in this age group. The company expects results “around the middle of 2021,” said Colleen Hussey, spokesperson for Moderna.
Based on the results, Moderna plans to evaluate the vaccine later this year in children aged 6 months to 11 years.
Infants may have some antibodies when they are born from vaccinated or infected mothers, but maternal protection is unlikely to last until the first year. And with their relatively weak immune systems, babies can be particularly susceptible to infection if community transmission is high.
The trials will also assess the vaccine’s safety in children – and, hopefully, allay parents’ fears. One-third of adults in the United States have said they do not plan to have their children vaccinated against the coronavirus, according to a recent survey by Verywell Health.
Given the low risk of Covid-19 in children, some parents might be skeptical about the urgency of vaccinating their children with a brand new vaccine, Dr Offit said. “For this reason, the vaccine should be subject to a very high level of safety,” he said.
More than 42 million people in the United States have been vaccinated so far, with few lasting side effects. And the FDA has several systems in place to carefully monitor any serious reactions to the vaccine.
“They’re really looking at the data very, very closely,” Dr. Oliver said. “As a pediatrician and a mom, I have no doubts that these systems work.”
Once a vaccine for children is available, schools can reintroduce extracurricular activities that involve close contact, such as orchestral practice, team sports, and choir. But in the meantime, there’s plenty of evidence that schools can reopen with other precautions in place, Dr Oliver said.
“I don’t think we should expect to have a vaccine to open schools in the fall,” she said. “We should now plan to open schools.”
Dr Oliver also urged parents to make sure children are immune to other illnesses. According to the CDC, orders for children’s non-influenza vaccines under the Vaccines for Children program are down by about 10.3 million doses.
“Now is the time to really catch up on the missed doses of these vaccines,” she said. “Measles, HPV, tetanus boosters, pertussis boosters – these are all really important.”