Many parents in the U.S. have been waiting to hear that the nation’s youngest children—those under 5 years old—can be vaccinated against COVID-19. On June 15, a panel of experts convened by U.S. Food and Drug Administration, and determined that the two vaccines made by Pfizer BioNTech and Moderna are both safe and effective for children 6 months and over.
The FDA’s panel voted unanimously—21-0—that the benefits of Moderna’s vaccine outweigh its risks for kids ages 6 months through 5 years of age. They also voted unanimously that the benefits of Pfizer-BioNTech’s vaccine outweigh risks for kids ages 6 months through 4 years.
The FDA generally follows its advisory committee’s recommendations and will therefore likely approve the shot for an emergency. The U.S. Centers for Disease Control and Prevention will consider the information and then make a decision about whether or not to recommend vaccinations for the age group.
Children aged 6 to 12 months could be vaccinated against COVID-19 if the CDC approves. This would make them the youngest age groups eligible. Despite the low incidence of COVID-19 among this population, hospitalization rates are steadily increasing due to Omicron-related variants dominating. The CDC reports that more than 2,000,000 COVID-19 cases have been reported among children under 4 since the beginning of the pandemic. More than 440 people died.
While members of the FDA committee widely felt that parents should be able to vaccinate their young children against COVID-19, some argued it’s important to keep the disease’s relatively modest effects on kids in perspective. In response, Dr. Arthur Reingold, head of epidemiology at the University of California, Berkeley’s School of Public Health, noted that kids are routinely vaccinated against diseases that carry low risks of hospitalization and death—and COVID-19 should be no different.
Other committee members said vaccination’s benefits don’t stop at preventing disease. The shots could also reduce kids’ odds of developing complications like Long COVID and offer some freedom to families that have remained largely isolated until their youngest members could be vaccinated.
Pfizer-BioNTech’s pediatric vaccine
Pfizer BioNTech vaccines for children 6 months and up are three shots. Each dose is one-tenth of what is given to adults. The children would be given two doses, three weeks apart. A third dose will follow at least two more months.
The antibody levels produced by the children in a study by more than 4,500 kids was compared with those of vaccinated adults 16-25 years. Researchers were able to determine how many antibodies protect against COVID-19. In the pediatric group, three-dose vaccine efficacy against symptomatic disease was 80.4% during a time when Omicron was circulating widely in the U.S.—though that estimate was based on such a small number of cases that it’s difficult to draw firm conclusions about how protective it is in real-world situations.
It’s been a long road for the Pfizer-BioNTech vaccine. Following data collection on a two dose course of vaccines, Pfizer-BioNTech began to submit their vaccine for FDA approval. Omicron’s dominance in the U.S. meant that the two doses of vaccine generated low levels of immunity. Pfizer BioNTech and FDA decided to wait until additional data was provided by the companies about whether adding another dose of the vaccine would enhance levels of virus-fighting antibody levels and, therefore, immunity against COVID-19. In May, the company provided these data.
Moderna’s pediatric vaccine
Moderna’s vaccine for children ages 6 months through 5 years old is given in two shots, and each dose is one-quarter the dose of that used in adults. Moderna vaccine would be administered in two doses, each four weeks apart.
Moderna’s two-dose vaccine was tested in over 6,300 children. Children between the ages of 2 and 5 were able to prevent symptomatic disease by about 37%. The effectiveness of the shots was about 50% for children aged six months to two years.
These are the similarities and the differences
The biggest difference between these vaccines is how many shots they require: Moderna requires two shots and Pfizer BioNTech needs three.
After trial results revealed that only two doses of the vaccine for children were effective in stimulating an immune response, Pfizer BioNTech switched to three doses. Pfizer officials stated at the FDA meeting that they wanted to prevent side effects, such as fevers. This could discourage parents from getting their child vaccinated.
The dosages will vary between companies. However, the doses given to children younger than adults for the most part are lower than the doses used for older children. This is done in an effort to balance side effects and protect the child. They can range from minor side effects such as swelling or fever at the injection location to more serious conditions like inflammation of the heart tissues (MIS)-C, which can cause inflammation throughout the body.
The vaccines did not cause more harm than adults and were considered relatively safe. However, the committee paid attention to myocarditis risk, which is an inflammation of heart tissue that can be seen in young men between 16- 25 years of age. The CDC’s vaccine side effects database did not reveal a higher rate of the condition among younger children.
Next, what’s the next step?
Parents will have to decide which vaccine their children will get if the CDC recommends them. Moderna’s two-dose regimen could be more convenient and mean fewer office or pharmacy visits, compared to Pfizer-BioNTech’s three-dose schedule. Children would take much less time to get fully vaccinated. On the other hand, Pfizer-BioNTech’s three doses appear to provide higher levels of virus-fighting antibodies.
Committee member Dr. Paul Offit, director of Children’s Hospital of Philadelphia’s Vaccine Education Center, was concerned by Pfizer-BioNTech’s “surprisingly poor” vaccine efficacy after two doses. He and other panelists worried that parents won’t realize their children aren’t well protected until after their third shots—especially since kids in the same age group only need two doses of Moderna.
Continue reading: FDA Recommends the Emergency Authorization of Moderna’s COVID-19 Vaccine for Children Ages 6 to 17
However, some children may need to receive additional vaccines, as the vaccines were originally designed for the SARS/CoV-2 virus. Omicron is more able than any other variant to overcome the immune system resulting from the vaccines. That’s why the FDA and CDC now recommend that all adults receive at least one booster after their initial two-dose vaccination with either Pfizer-BioNTech or Moderna’s shots, in order to push waning levels of virus-fighting antibodies back up to levels that can protect against infection and severe disease.
Although the meeting did not include the evaluation of the need to add doses, experts from the previous meetings will meet again in June 28th to talk about boosters and the future COVID-19 vaccine plans. They’ll also review data related to new vaccines developed to target Omicron specifically.
“I think Omicron has brought us to the point where we need to redefine what the primary series of vaccination against COVID-19 should be,” says Dr. Kristin Moffitt, an infectious disease specialist at Boston Children’s Hospital (who does not serve on the FDA committee). “We are in completely uncharted territory and in a very dynamic situation, since the virus and its evolution is really what is driving the bus here.”
It’s possible, for example, that by the fall, health officials may have enough data from newer, Omicron-specific vaccines to decide that everyone—including children—should receive at least one dose of those updated vaccines to remain protected during the winter season.
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