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

• None Millions of US adults are eligible for booster shots of Pfizer's vaccine.
• None Authorities are waiting for more data before recommending boosters for Moderna's and J&J's vaccines.
• None New charts suggest the protection Moderna's vaccine offers may last longer than Pfizer's and J&J's.
• None See more stories on Insider's business page.

The US is 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.

Booster doses are most recommended for adults age 65 and up, who generally don't have the same kind of strong, lasting immune response to vaccines as younger people.

But there's no federal guidance about whether people who've gotten Moderna's or Johnson & Johnson's COVID-19 vaccines might need a boost.

Emerging evidence suggests that people on #TeamModerna may not need a booster as much as others.

Last week, the Centers for Disease Control and Prevention released data sets from hospitals around the country. That data is starting to indicate that people who got Moderna's vaccine are less likely to be hospitalized than people who got Pfizer's or Johnson & Johnson's.

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

Dr. Robert Atmar, who's leading a pivotal COVID-19 booster study at Baylor College of Medicine, said that while he wouldn't be surprised if J&J vaccine recipients got 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 that of the other vaccines.

This data, collected from hospitals in 20 cities, suggested that Moderna's vaccine protected people against hospitalization for longer than Pfizer's and Johnson & Johnson's vaccines.

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

One reason Moderna's vaccine may be holding up better in long-term protection is its higher dosage.

Moderna's shot consists of 100 micrograms of mRNA vaccine, while Pfizer's has 30 micrograms. That may mean lighter side effects for Pfizer's shot — but in the long run, the protection might not be as strong.

A study of hospitals in New York, Minnesota, Wisconsin, Utah, California, Oregon, Washington, Indiana, and Colorado found that Moderna's vaccine was associated with a lower proportion of hospitalizations than Pfizer's or J&J's among vaccinated people.

Another possibility is that the four-week interval between Moderna's doses is better than the three-week wait between Pfizer's shots.

Both vaccines are still great at preventing severe disease and hospitalization, especially in adults under 65.

But data from five veterans-affairs medical centers in the US suggested that Moderna's vaccine was superior at protecting older adults, with an effectiveness of 87% against hospitalization in patients 65 and up. Pfizer's vaccine was 77% effective in that same group.

Since the Delta variant took over in the US, recipients of Moderna's and Pfizer's vaccines have gotten sick more often. But the Moderna vaccine's effectiveness against hospitalization for people over 30 is looking slightly stronger - for now.

These estimates of vaccine effectiveness, broken down by age group, come from data on over 74,000 hospitalizations across 187 hospitals nationwide.

We can see that Moderna outperformed Pfizer among adults 30 to 64. From June to August, Moderna's vaccine effectiveness against hospitalization was 99% among 30- to 49-year-olds and 91% among 50- to 64-year-olds.

Pfizer's vaccine during that same period was roughly 82% effective among 30- to 49-year-olds and 84% effective among 50- to 64-year-olds.

In adults 18 to 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 affecting how well the 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. But older adults remain more vulnerable to severe COVID-19 outcomes, even when they're vaccinated.

This data, taken from more than 250 hospitals across 14 states, combines Pfizer's and Moderna's vaccine effectiveness against hospitalization in one chart. It indicates that the vast majority of COVID-19 cases and deaths nationwide are 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."