Moderna said on Tuesday that its coronavirus vaccine, authorized only for use in adults, was powerfully effective in 12- to 17-year-olds. In a clinical trial of the vaccine in adolescents, there were no cases of symptomatic Covid-19 among fully vaccinated teens, the company reported in a news release.
Moderna plans to apply to the Food and Drug Administration in June for authorization to use the vaccine in adolescents. If approved, its vaccine would become the second Covid-19 vaccine available to U.S. adolescents, after federal regulators authorized the Pfizer-BioNTech vaccine for 12- to 15-year-olds earlier this month.
The Pfizer shot was initially authorized for use in people 16 and older, while Moderna’s has been available for those 18 and up.
The Moderna results are not a surprise and match what Pfizer reported in its trial of young adolescents. But they add to a growing body of evidence that the vaccines are safe and effective in children.
“We were pretty excited to see the data, and we’re excited to see that the numbers look very good,” said Dr. Yvonne Maldonado, a pediatric infectious disease specialist at Stanford Medicine and chair of the American Academy of Pediatrics Committee on Infectious Diseases.
She added, “People are going to be more comfortable being able to go back to school. They’re going to be able to do more activities socially. I do think it’s going to make a big difference in opening our society back up.”
On Monday, Mayor Bill de Blasio said that all public school students in New York City, the largest school system in the United States, would return to in-person learning in the fall. Several other states, including Connecticut, Illinois, Massachusetts and New Jersey, have also indicated that they will restrict online learning.
The widespread availability of safe, effective vaccines for teenagers could allow middle and high schools to operate more safely and restore at least some sense of normalcy.
“Having adolescents vaccinated against the virus is really going to limit spread in school to a great degree,” said Dr. Sean O’Leary, a pediatric infectious disease expert at the University of Colorado Anschutz Medical Campus. “It potentially could even change mask requirements for school, depending on the level of vaccination uptake. I’m looking forward to a much different school year next year, primarily because of vaccination.”
But Moderna’s announcement comes at a time when there is already a glut of vaccines in the U.S., and amid signs that demand for vaccination may be flagging. And the authorization of vaccines for American adolescents has already raised questions about the ethics of vaccinating children, who are at relatively low risk for serious disease, while many countries do not have enough doses for their health care workers.
“It’s a tough conversation, because we are glad to see vaccine distribution safely expand to children,” said Saskia Popescu, an infectious disease epidemiologist at George Mason University. “But frankly, it’s hard not to see this as privileged when a majority of the world’s essential workers are struggling to get access to vaccines.”
The Moderna results, which the company announced in a statement, are based on a clinical trial that enrolled 3,732 people ages 12 to 17, two-thirds of whom received two vaccine doses. There were no cases of symptomatic Covid-19 in fully vaccinated adolescents, the company reported. That translates to an efficacy of 100 percent, the same figure that Pfizer and BioNTech reported in a trial of their vaccine in 12- to 15-year-olds.
“It’s really great news,” said Akiko Iwasaki, an immunologist at Yale University. “These vaccines are working really well in all the age groups and potentially even better in the younger people.”
Moderna also reported that a single dose of its vaccine had 93 percent efficacy against symptomatic disease.
The side effects were consistent with what has been reported in adults: pain at the site of the injection, headache, fatigue, muscle pain and chills. “No significant safety concerns have been identified to date,” the company said. The adolescents in the study will be monitored for a year after their second dose.
The authorization of a second vaccine for adolescents could help convince more parents, some of whom have expressed reluctance about having their children vaccinated, that the shots are safe, experts said. “Most parents vaccinate their children,” Dr. O’Leary said. “With the Covid vaccines, we’ve seen a little bit more hesitancy, but the further along we get demonstrating safety and effectiveness, the more people we’re seeing wanting the vaccine.”
It would also give parents and teenagers a choice between vaccines, although experts noted that the Pfizer and Moderna vaccines appear to be equally safe and effective.
“This really give parents, I think, a little bit more confidence,” said Rupali Limaye, an expert on vaccine use and hesitancy at Johns Hopkins University. “If they’ve had personal experience, for example, with one of the mRNA products and not the other, they might feel more comfortable then saying, ‘You know, I had a great experience with Moderna, so I really want my child to get Moderna.’”
But because the Pfizer and Moderna vaccines both require two shots, spaced several weeks apart, ensuring that all teens have access to the vaccine may remain a challenge. “I think we’ll still unfortunately not be able to reach more underserved populations that are facing vaccine disparities, because it’s still the two-dose regimen,” Dr. Limaye said. Authorizing a one-dose vaccine, like the Johnson & Johnson shot, for use in adolescents may help close these gaps, she said.
The U.S. already has enough doses to vaccinate adolescents many times over. There are approximately 25 million American children between the ages of 12 and 17, according to estimates from the U.S. Census Bureau. That is roughly the same number of shots that Pfizer and Moderna are distributing, in total, per week in the U.S.
“Right now, we have more than enough supply to vaccinate our teens,” said Dr. Celine Gounder, an infectious disease specialist at Bellevue Hospital Center in New York. “So it’s not so much that the Moderna vaccine is critical for having supply for our population, but rather, having a second vaccine come online for that age group that could be available to the rest of the world — I think that is important.”
Many other countries, however, will not be ready to vaccinate their adolescents for quite some time. Although more than 1.7 billion vaccine doses have been administered globally, there are enormous inequities between countries; 84 percent of doses have gone to people in high- and upper-middle-income countries. Just 0.3 percent have gone to low-income countries.
“A huge proportion of the world’s population actually lives in countries that don’t have access to any doses right now at all,” said Andrea Taylor, assistant director of programs at Duke University’s Global Health Innovation Center. “In one country we are looking at covering children, and in more than 100 other countries we are desperately scrambling to try to inoculate the most vulnerable populations.”
Covax, a global initiative that aims to improve access to vaccines in low- and middle-income countries, has fallen far short of its distribution goal so far. Moderna and Pfizer have pledged to deliver tens of millions of doses to Covax by the end of 2021. Given the vaccine shortages — and dire case numbers — in many other countries, the companies should consider delivering those shots sooner, even if it means postponing the vaccination of adolescents, said Prashant Yadav, an expert in health care supply chains at the Center for Global Development in Washington, D.C.
“If they can upfront that and deliver that now, that will give Covax the option of vaccinating the high-risk individuals in a large number of low-income countries,” he said.
The World Health Organization has called on countries with ample vaccine supply to share their shots with the world. President Biden has pledged to send 80 million vaccine doses — including shots from Pfizer, Moderna, Johnson & Johnson and AstraZeneca — abroad, although many activists and global health experts have called on him to do more.
“It feels like, ‘OK, we are putting this behind us,’” Ms. Taylor said. “We’re moving forward and starting to make summer vacation plans. It can be really hard to remember that much of the world actually is still in crisis.”
Noah Weiland contributed reporting.