4 charts show why Moderna vaccine recipients may not need boosters as much as people who got Pfizer’s vaccine

Pfizer and Moderna vaccine vials
Vials of the Pfizer (left) and Moderna (right) COVID-19 vaccines. Hazem Bader/AFP via Getty Images
  • Millions of adults across the US are now eligible for booster shots of Pfizer‘s vaccine.
  • Federal authorities are still waiting for more data on Moderna and Johnson & Johnson before recommending a boost to those vaccines.

The US is now offering booster doses of Pfizer’s COVID-19 vaccine to tens of millions of people who’ve been fully vaccinated with Pfizer’s shots for at least six months.
Man in a mask getting his third booster shot of Pfizer vaccine injected into his right arm by a healthcare worker (also masked).
Booster shots began to be administered at the VA Hospital in Hines, Illinois on September 24, 2021. Scott Olson/Getty Images
Booster doses are most recommended for adults age 65 and up, who don’t generally have the same kind of strong, lasting immune response to vaccines as younger people. 
But there’s not yet any federal guidance about whether, or when, people who’ve gotten Moderna or Johnson & Johnson’s COVID-19 vaccines might need a boost.
A healthcare worker holds a syringe inserted into a vial of pfizer's comirnaty vaccine
Booster shots are being offered to some adults in the US who got Pfizer’s vaccine, called Comirnaty. Jens Schlueter/Getty Images
More evidence is beginning to emerge suggesting that people on #TeamModerna may not need a booster as much as others, though.

Last week, the Centers for Disease Control and Prevention released data sets from hospitals around the country, which are starting to show that people who’ve gotten Moderna’s vaccine are less likely to be hospitalized than those with Pfizer or Johnson & Johnson.

Another CDC report released earlier in September suggested that Moderna’s two-dose vaccine reduced the risk of hospitalization by 93%. For Pfizer, that figure was 88%, and for Johnson & Johnson it was 71%.

Dr. Robert Atmar, who’s leading a pivotal COVID-19 booster study at Baylor College of Medicine, says while it “wouldn’t surprise me” if J&J recipients get a booster recommendation soon, “for the Moderna, it is an open question.”

The protection Moderna’s vaccine offers against hospitalization seems to last longer than other brands.
Chart showing vaccine effectiveness appears to wane more with pfizer than with moderna after 4 months
This data, collected from hospitals in 20 cities across the country, suggests that Moderna’s vaccine protects people against hospitalization for longer than both Pfizer and Johnson & Johnson.

After four months, Moderna’s vaccine remained 92% effective at preventing hospitalizations, while Pfizer’s was 77% effective, and J&J’s 68%.


One reason why Moderna may be holding up better in long-term protection is because the vaccine dosage is higher.
Vaccine effectiveness chart showing slightly lower effectiveness against hospitalizations for pfizer vaccine than for moderna
Moderna’s shot consists of 100 micrograms of mRNA vaccine, while Pfizer’s is 30 micrograms. That may mean lighter side effects for Pfizer’s shot, but in the long run the protection might not be as strong.  

According to a study of hospitals in New York, Minnesota, Wisconsin, Utah, California, Oregon, Washington, Indiana, and Colorado, Moderna’s vaccine is triggering far fewer hospitalizations when people aged 65 and older do get sick. 

Another possibility is that the four week interval between doses of Moderna is better than the three week waiting time between shots one and two of Pfizer.
Vaccine effectiveness against hospitalization lower with pfizer than moderna
Both vaccines are still great at preventing severe disease and hospitalization, especially in adults under the age of 65.

Still, this data from five veterans affairs medical centers in the US suggests that Moderna’s vaccine is superior at protecting elderly adults, with a vaccine effectiveness of 87% against hospitalization in patients aged 65 and up, whereas Pfizer is 77% effective in that same group. 

Since the Delta variant took over in the US, both Moderna and Pfizer recipients are getting sick more often. But Moderna’s vaccine effectiveness against hospitalization, for people over age 30, is looking slightly stronger – for now.
Charts showing vaccine effectiveness against hospitalization remains very high for both vaccines
These estimates of vaccine effectiveness, broken down by age group, come from data on over 74,000 hospitalizations across 187 hospitals nationwide. 

Here, we can see that Moderna has been outperforming Pfizer among adults ages 30-64. From June to August, Moderna’s vaccine effectiveness against hospitalization was 99% in the 30-49 year old age group and 91% among 50-64 year olds. Pfizer’s vaccine during that same time period was roughly 82% effective among 30-49 year olds, and 84% effective among 50-64 year olds.

But in younger adults, ages 18-29, the two vaccines performed almost identically, with vaccine effectiveness against hospitalization of 82% for Moderna and 85% for Pfizer.

It’s tough to know exactly how the arrival of the Delta variant in the spring may be impacting  how well vaccines work.

Whichever way you slice the data, all the vaccines are still pretty stellar at their primary job – keeping people alive and out of the hospital. Still, older adults remain more vulnerable to severe COVID-19 outcomes, even when they’re vaccinated.
Vaccine effectiveness chart showing protection remains high against hospitalization
This data, taken from more than 250 hospitals across 14 states, combines both the Pfizer and Moderna vaccine effectiveness against hospitalization in a single chart. It shows the vast majority of COVID-19 cases and deaths nationwide are now among unvaccinated people. 

“We will not boost our way out of this pandemic,” CDC Director Rochelle Walensky said during a White House COVID-19 briefing on Friday. “The most vulnerable are those unvaccinated.”