New data suggests that Pfizer’s COVID-19 vaccine was far less effective during the recent omicron surge in New York at preventing infections among 5- to 11-year-olds, who receive a smaller dose than teens and adults.
In mid-December 2021, the vaccine was 68% effective at preventing infection among young kids. By late January, amid the omicron surge, it was only 12% effective at preventing infections among kids ages 5 to 11.
Fortunately, the vaccine continued to fulfill its primary function and provide strong protection against hospitalization and death.
Still, in light of the emerging evidence, some parents are wondering why 5- to 11-year-olds can’t just get the bigger, seemingly more effective dose. Here’s what vaccine experts have to say.
First, parents should remember the vaccine does a good job of keeping kids healthy — even in its current dosage
The experts HuffPost spoke to emphasized one fact above all else: Pfizer’s COVID-19 vaccine remained effective at preventing kids from getting seriously sick, even during the omicron surge.
Vaccine effectiveness against hospitalization dipped to 48% during omicron, but there was major variation in confidence intervals (basically, a measure of how certain researchers are of the data), making it difficult to draw solid conclusions. A lot of that has to do with the fact that overall hospitalizations of children remained pretty low, so there simply wasn’t a lot of data for the researchers to work with.
And pediatric specialists say they’re pleased that kids continue to be protected against the most serious outcomes.
“I don’t want parents to be discouraged by this data. I’m not discouraged by it,” said Dr. Ruth Kanthula, a pediatric infectious diseases specialist with MedStar Health in Maryland.
“Omicron was a really mutated virus,” Kanthula added. “The fact that we even had any response to it is actually reassuring, and the fact that people were kept out of the hospital and from having serious infection because of [the vaccine] is great.”
She urged parents of kids ages 5 to 11 who have not gotten their children vaccinated to do so. So far, only about a quarter of American children in that age group are fully vaccinated.
Finding the right dosage through clinical trials takes time
Though it may seem like the COVID-19 vaccines were developed quickly — and indeed, they were made available to millions of people around the world in record-breaking time — months of research went into studying the best dosage. That research is still ongoing in children 4 and under, who are not yet eligible to be vaccinated.
So before researchers settled on the 10 microgram dose of the Pfizer vaccine in children ages 5 to 11, they looked at both lower and higher doses — including the 30 microgram dose given to adults. Ultimately, researchers on those initial trials concluded that the 10 microgram dose gave the best balance of what they were looking for: a robust immune response and relatively minimal side effects.
Before the vaccine dose is changed for kids (if it ever changes), there must be clinical trials. The initial trials were conducted before the omicron variant emerged.
“Why not just give 5- to 11-year-olds the 30 microgram dose? It hasn’t been studied yet,” said Dr. Matthew Harris, medical director of the vaccine program at Northwell Health in New York.
For example, he pointed to the risk of post-vaccination myocarditis, which remains very rare but is higher among young males ages 12 to 39. Could that increase in younger children if they’re given bigger doses? Those are the types of questions researchers need to tackle before they make any changes.
Also, kids are not just smaller adults
One of the challenges of being a pediatrician, Kanthula said, is that children aren’t just smaller adults. So doctors can’t just shrink down what they do in the adult population and hope it works.
“Children are physiologically different from adults,” she said, adding that older children are physiologically different from younger children in everything from their height and weight to their heart and respiratory rates.
“They’re all physiologically different. Their immune systems are different. And they respond differently to different things,” she said.
Again, that’s why doctors can just apply the clinical data from one patient population to another.
But experts do think the doses or number of shots kids get could change down the road
While public health experts are hopeful that we’re on the cusp of endemic COVID-19, that does not mean the virus will no longer be harmful, nor does it mean that it will fade away.
“This isn’t going anywhere,” Harris said. He’s “quite certain” that vaccine manufacturers like Pfizer and Moderna are asking exactly these types of questions about dosage and whether it should change — particularly as more variants arise.
Another possibility is that children might end up getting a third shot at their current dosage ― not so much as a booster but as part of their primary routine, Kanthula added.
Both Harris and Kanthula noted the frustration and confusion many parents may feel as this plays out in real time and best practices shift based on new information. But the core message stays the same, they said: Get your child vaccinated now if they’re eligible. The data still clearly shows it will help keep them safe.
Experts are still learning about COVID-19. The information in this story is what was known or available as of publication, but guidance can change as scientists discover more about the virus. Please check the Centers for Disease Control and Prevention for the most updated recommendations.