Pfizer vaccine

Maria Powers, an advanced practice nurse at Cheshire Medical Center in Keene, prepares a Pfizer-BioNTech COVID-19 vaccine in December.

Health experts are touting Pfizer-BioNTech’s announcement that its COVID-19 vaccine was 100 percent effective in a recent study of 12- to 15-year-olds as a huge step in fighting against the pandemic.

“Given that they are very social animals, these teenagers, they are likely big spreaders of this virus in our community, so if we can inhibit that spread, that would be a major contribution,” said Dr. William Schaffner, a professor of medicine in the Division of Infectious Diseases at Vanderbilt University in Nashville, Tenn.

The trial involved 2,260 children between 12 and 15 in the United States and included people who had contracted COVID-19 and those who hadn’t, according to a news release Wednesday from Pfizer.

Currently, Pfizer’s vaccine — which is administered in two doses, 21 days apart — has FDA approval only for those 16 and older. In that group, the vaccine was shown to be 95 percent effective at preventing infection.

In the vaccine’s trial among 12- to 15-year-olds, 18 cases of COVID-19 were recorded in the group that did not receive the vaccine, while no infections were found in those who did.

While that works out to an efficacy of 100 percent for this age group, the trial’s sample size is relatively small, so the efficacy rate could go down over time, according to Dr. Aalok Khole, an infectious-disease physician at Cheshire Medical Center in Keene.

“But with the efficacy we saw in adults, it isn’t surprising that we are seeing that be mirrored in the younger age groups,” he said.

Participants tolerated the shot well, according to the release, with side effects mostly consistent with those seen in adults, such as soreness at the injection site, headache and fatigue.

Those involved with the study will be monitored for an additional two years, the release notes.

The companies plan to submit their findings to the Food and Drug Administration for another emergency-use authorization, which would expand the vaccine’s approved use to this age bracket.

“So far all we have seen is a press release, not the actual data,” Schaffner said. “... But given all the experience we now have with vaccinating adults, I suspect that this is a study in this age group that is going to be sufficient for the Food and Drug Administration to accept their application.”

While it’s rare for teenagers to develop serious complications from COVID-19, getting them vaccinated would contribute to a community’s herd immunity, which happens when enough people have been immunized to stop the virus from circulating. Those who cannot get vaccinated still benefit from herd immunity because it’s harder for the virus to spread from person to person.

“The more people in the community that can become vaccinated, the better for all of us,” said Robert Malay, superintendent for N.H. School Administrative Unit 29, which covers Keene and six other area communities. “If the 12- to 15-year-olds are approved to receive the Pfizer vaccine through the FDA, then I think that’ll be very beneficial to our communities as a whole, and that’ll obviously impact our schools as we are getting broader immunization in our schools.”

And as Schaffner pointed out, immunizing the younger population — who often can be carriers of the disease — could also lessen COVID-19 transmission.

It’s still unclear whether the vaccines prevent people from spreading the viral disease, according to the Centers for Disease Control and Prevention. But, based on data from a recent real-world study by the federal agency, the CDC said it does not appear that vaccinated people can carry the virus.

Similar to Schaffner, Khole said having more people eligible for immunizations is always a plus.

“Not that it is a requirement ... but it is always an added layer of protection if we get a chance to vaccinate more people,” he said.

As part of this effort, Pfizer recently started a global clinical trial among children.

The study is evaluating the vaccine’s safety, tolerability and immune response in three age groups: 5- to 11-year-olds, 2- to 5-year-olds, and those age 6 months to 2 years.

The 5- to 11-year-old group started receiving shots last week, according to Pfizer’s news release, and the 2- to 5-year-old cohort is slated to start next week.

“I’m sure this is going to be an active circuit of work,” Khole said.

Olivia Belanger can be reached at 352-1234, extension 1439, or Follow her on Twitter @OBelangerKS.