Dr. Jeremy Faust won’t vaccinate his 3-year-old until there’s more data on how well it works

“I will enthusiastically vaccinate my 3-year-old daughter when we see that data.”

A 5-year-old girl receives her first dose of the Pfizer COVID-19 vaccine from a nurse in the cafeteria of the Pittsburgh Langley K-8 school in Pittsburgh on Saturday, Jan. 8. Emily Matthews/Pittsburgh Post-Gazette via AP

Dr. Jeremy Faust, a Boston physician, public health researcher, and parent, will wait just a little longer to vaccinate his 3-year-old, even if authorities authorize Pfizer’s COVID-19 vaccine for her age range. 

This isn’t due to any lack of confidence in vaccines on Faust’s part; rather, he says, there just isn’t enough data to support the vaccine series Pfizer is suggesting for her age range. 

“The data that we need to see is the data that will show us that the vaccine is both safe, which we know it is, and that it provides real protection,” the Brigham and Women’s emergency physician said on CNN this week. “I will enthusiastically vaccinate my 3-year-old daughter when we see that data.”


Pfizer asked the Food and Drug Administration (FDA) to clear a 2-dose vaccine course for children under the age of 5 last week. Federal regulators pressed Pfizer, and its partner BioNTech, to submit a request even though the trial had generated mixed results. 

For children ages 6 months to 2 years, the vaccine had succeeded, meaning it provided an adequate immune response. But for children ages 2 to 4, this was not the case. Faust described this revelation, which happened in December, as “a crushing setback,” saying he is “so ready” for his daughter to be vaccinated. 

After the initial findings in December, Pfizer set out to study the effectiveness of a third dose in all ages, wrote Faust, including kids 6 months to 2 years and ages 5 to 12 — even though data for those two groups has shown they respond adequately to a two-dose series. 

“The only public health rationale I can think of is that it would be simpler for parents to hear one consistent message: your kids need 3 doses,” no matter what the age, Faust wrote. 

In reality, Faust said, trials have already found safe and effective vaccine regimens for all ages except  2 through 4. He said Pfizer could have instead decided to study a two-dose series of larger 10-microgram injections for 3- and 4-years-olds — this would be the same vaccine regimen as children ages 5 to 12. 


“Unity is not the goal. Safety and efficacy are,” Faust wrote. “Pandemics are messy. I’d rather have pediatricians spend a few minutes with parents helping them understand everything than endure months of delays just so that the conversations (and public communications) can be a bit smoother.”

The vaccine series that was submitted to the FDA last week was deemed inadequate by Pfizer itself, wrote Faust. He said the justification is that omicron changed the situation, and getting two doses into kids now will allow for a quicker completion of vaccination when the third dose is shown to be effective. 

“That assumes that the 3rd dose will work. Many believe it will. But many also assumed the 2-dose series would work, including Pfizer scientists,” Faust wrote. “Look, science is difficult. If the answers were easy, we wouldn’t need science.”

Faust pointed out that there are downsides to the gamble Pfizer is taking right now — if a third dose fails and we have to look to a fourth and higher dose, it’s possible that it will generate intolerable side effects for many children. 

He called on Pfizer to release any interim data it has on a third dose for young children. 


“No matter what we say, some will believe that 2 doses of the vaccine does provide adequate protection to their kids, simply by virtue of its availability to the public,” Faust wrote “That could cause them to take risks they otherwise are not comfortable yet taking. Do we want to own that?”

Faust said he is less interested in the vaccination rate six weeks from now than the rate 6-12 months from now. 

“Allowing parents to vaccinate their children under age 5 now will certainly increase the number of vaccinated kids between now and March,” Faust wrote. “That will feel like progress. But will it really be? This strategy could come at a cost if other parents lose faith in the scientific process” if the vaccine dose for ages 2-4 proves ineffective.

He expanded on all these points in a blog post

“It’s long been known that people make bad decisions when they’re tired,” Faust wrote. “I’m worried that our leaders and our public health officials are tired, like the rest of us, and that they’re falling into that trap. Now, more than ever, when we are most at risk of making a mistake, is when we should especially insist on following the science.”


This discussion has ended. Please join elsewhere on