“Before you put it into the children, you’re going to want to make sure you have a degree of efficacy and safety that is established in an adult population, particularly an adult, normal population,” he said Sunday on NBC’s “Meet the Press.” NIAID did not respond to requests for comment about the pediatric trials or Fauci’s suggested timeline. Moderna posted a trial design Wednesday on the National Institutes of Health website but declined to offer any additional information about when it will begin recruiting participants. The randomized study would include approximately 3,000 participants who are 12 to 18 years old.
The wait has prompted pediatricians and other public health experts to voice concerns that further delays endanger at-risk children, hinder efforts to return schools to normalcy and stall herd immunity.
Children’s immune responses are different from that of adults, so there is a consensus that pediatric trials are critical for testing the safety, efficacy and immunogenicity (or effective immune response) of vaccines on kids. But some experts have said testing on children should have begun sooner, especially after the successful adult trials.
“To be completely frank, many of us are disappointed with this timeline,” said Andrew T. Pavia, the chief of the pediatric infectious diseases division at the University of Utah. “We think that there was enough safety data emerging and early efficacy data a month or six weeks ago that the adolescents could have been added earlier.”
Even after vaccine producers announce expanded trials for children, it will still take time to recruit young participants, gather data and get approval, not to mention scaling production, Pavia said.
A representative for Pfizer said the company had shared safety data on about 100 children between ages 12 and 15 when it submitted its emergency use authorization application to the U.S. Food and Drug Administration, but enrollment “may” expand and more information about efficacy and immunogenicity is being collected. The company could not say when the vaccine might be publicly available for children.
The inclusion of children in Pfizer’s third phase could mean the FDA may expedite approval for the age group older than 12, depending on the data.
The lag in testing the experimental vaccines on children prompted American Association of Pediatrics President Sally Goza to write to federal leaders in September, arguing pediatric trials were essential for curbing the pandemic, as older children could transmit the virus as much as adults. More than 1.1 million U.S. children have tested positive for the novel coronavirus, according to the group of pediatricians.
“While the likelihood of spreading the disease may vary among different aged children, we know that children can and do spread the virus to household members, grandparents, teachers, and other children,” Goza wrote to Health and Human Services Secretary Alex Azar and FDA Administrator Stephen Hahn.
Goza also stressed the educational, social and psychological effects of the pandemic on children who have lost precious time in schools, on playgrounds and with friends.
Several experts have expressed hopes that a vaccine could be available for children before the start of the new school year, putting an end to the disruptions in learning. One is Evan Anderson, a pediatrician at Children’s Healthcare of Atlanta, who co-wrote an article published in the journal Clinical Infectious Diseases in September that pushed for pediatric trials to begin immediately.
But, Anderson said, the window is quickly closing for those younger than 12 who have not yet been included in the trials.
“The window is closing on any chance of getting an approved vaccine for children before next school year, and it realistically may have already closed,” he told The Washington Post.
Among the numerous indirect benefits of vaccinating children sooner rather than later, according to his article, would be the end of drastic inequalities in education that come with remote learning and the start of an economic recovery when parents are able to return to offices.
It is also critical to vaccinate such a significant proportion of the general population, said Koen Van Rompay, a virologist at the California National Primate Research Center, as those under 18 made up more than 22 percent of the U.S. population in 2019, according to Census Bureau estimates.
Van Rompay, who is part of a research team that has tested vaccines for HIV and covid-19 in young rhesus macaques, said children tend to have stronger immune responses to vaccines than older people, which is one reason immunizations for measles, mumps, rubella and other viruses are given early in life.
“It basically contributes to herd immunity,” Van Rompay said. “If you have the children immune, meaning they are less likely to transmit, that would actually help to protect especially the older population, where it is more difficult to induce strong immune responses with vaccines.”