BOSTON — Some are in diapers, some are toddlers, others are knocking on the door of adolescence. All made history this week by getting their first shots in a trial to test the safety and efficacy of Moderna’s COVID-19 vaccine in kids.
The Phase 2/3 ‘KidCOVE’ study will eventually enroll 6,750 U.S. and Canadian children aged six months to just under 12-years-old. Participants will get two doses of Moderna’s mRNA vaccine spaced 28 days apart.
But there end the similarities with the adult vaccine trials. The KidCOVE study is ‘open label’ during the first part, meaning both participants and investigators know the substance being administered. In this case, everyone is getting the vaccine, and different dose levels will be tested.
No doubt, pediatric drug trials are a complicated business.
“Just getting the consent that you need from the people participating in the trial is a lot less straightforward,” said Dr. Stephen Kissler, an immunology and infectious disease researcher at the Harvard School of Public Health. “I think that’s part of the reason we expect the vaccine approval to go down by age group.”
Another reason for the lower priority assigned to study kids and the COVID-19 vaccine: the virus doesn’t affect them nearly as much as others.
“It’s less urgent for this particular disease,” Dr. Kissler said. “If this were primarily a childhood illness, if SARS-CoV2 happened to be causing an immense amount of mortality and morbidity in very young kids, you can bet that we would have been really focusing on developing a vaccine for that age group.”
Still, there are compelling reasons to vaccinate children, said Dr. Lindsey Baden from Brigham and Women’s Hospital, a co-principal investigator during the adult trials of the Moderna vaccine.
“We need to understand that all of us, children included, can get infected and can amplify the virus,” Dr. Baden said.
In fact, many children in the U.S. have become infected with the virus. The American Academy of Pediatrics reports that, so far, at least 3.28 million children have tested positive since the pandemic began, that’s 13% of the total. And while children generally don’t get terribly sick from COVID-19, they can transmit the infection to others.
“So there’s a possibility that if kids remain unvaccinated we could still see transmission of SARS-CoV2 amongst kids, and that might make it more difficult to control in the overall population,” Dr. Kissler said.
Not having a significant number of kids vaccinated could also defeat the ultimate goal of achieving herd immunity, Dr. Kissler added.
“We can still go a long way, it’s just one important goal,” he said. “We’ll still be able to slow down the spread. We’re blocking infection and blocking severe disease in the people who are most susceptible to severe disease. So even if we do see the continued spread of COVID-19, it will look like a different virus.”
One huge benefit that could come from the pediatric vaccine trial: a better understanding of whether the vaccines prevent viral transmission. That’s because investigators may need to evaluate vaccine effectiveness in a substantial number of study subjects who will be asymptomatically infected, since children very often show no signs of COVID-19 infection.
“And you do that by just taking a nasal swab of the people who are enrolled in the trial, probably weekly,” Dr. Kissler said. “And just seeing whether or not they turn positive, whether or not they show symptoms.”
The benefit? Those swabs would, or would not, pick up particles of the virus in the nasal passages.
“That’s really the thing I think we’re going to be most interested in,” Dr. Kissler said. “So hopefully that’s something they’re following closely.”
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