COVID Vaccines for Adults: 6 New Findings on Boosters

WebMD

01-07-2025

booster this year, maybe two.
That's what researchers concluded from the first real-world analysis after last year's recommendation that older adults – ages 65 and up – get the shot twice a year.
Among adults of all ages, a single COVID booster provided added protection against serious illness, found the study, which included data for nearly 500,000 adults during the 2023-24 COVID season. For those ages 65 and older, a second dose offered even better protection against serious illness.
The findings are important as the nation wrestles with questions about who should continue to get COVID booster shots (extra doses given after the first series). The CDC's vaccine advisory committee is expected to consider recommendations for the 2025-26 season in the coming months, but many leading professional medical organizations continue to recommend baseline vaccination and boosters for everyone ages 6 months and older.
"While we know that vaccines used to prevent COVID in the U.S. were found to be of high value earlier in the pandemic, question remains as to whether this value is still present now that nearly all persons have some degree of immunity" through prior infection or vaccination, said Richard Martinello, MD, chief medical officer at Yale Medicine and an infectious diseases professor at Yale School of Medicine in New Haven, Connecticut. "The results show that we should continue to recommend vaccination for our adult patients."
Indiana University professor Brian Dixon, MPA, PhD, was one of the researchers who worked on the analysis. He called the results "the most up-to-date information on whether COVID-19 vaccines continue to protect adults against hospitalization and seeking emergency care, regardless of their prior vaccination status or infection with the virus."
Here's what to know about the new study results, published Wednesday in JAMA Network Open:
COVID boosters still give you a lot of extra protection. Adults who got a booster had a 24% reduced risk of going to the emergency room or urgent care for COVID, compared to people who didn't get a booster. Boosters also reduced the risk of hospitalization by 29%, and intensive care unit admission or in-hospital death by 48%.
You ' re most protected during the two months after a booster. Vaccines reduced the risk of severe illness by 68% within the first 60 days.
"It is best to get the booster in the early fall, especially if the 60 days will be during the period people visit with family around the holidays," said Dixon, who is also director of the Center for Biomedical Informatics at the Regenstrief Institute in Indianapolis. "Additional protections after 60 days can be discussed with your medical doctor."
One booster reduced the risk of serious illness in older adults – but two boosters lowered it more. Among the 65-and-older crowd, those who got two doses had a 21% more reduced risk of needing urgent or emergency care for COVID, compared to those who only got one booster. Two doses also further reduced hospitalization risk by 18%. About 40% of the adults in the study were 65 or older.
Younger adults may want to consider twice-yearly boosters as well – particularly if the usual fall COVID season ever shifts, Martinello said.
"In my opinion, there is still a great deal of uncertainty on whether COVID will be a seasonal infection such as we see with influenza and RSV," Martinello said. If the virus turns out to be present year-round, "physicians will need to consider whether the recommendation for vaccinating every 6 months should be broadened."
Boosters give you added protection even if you ' ve already been infected with COVID. Before the study, most people had some degree of immunity from past infection and/or vaccination against the virus. Even so, people who didn't get new booster shots were more likely to seek care for serious COVID illness sooner than people who got a booster.
An annual COVID booster is about as effective an annual flu shot. Think of it this way: "The added protection from COVID boosters is similar to preparations one might do if a hurricane was approaching your home," said Dixon. "You might have a well-built house, but if you board up the windows and reinforce your doors, then your home is better protected against the high winds and hail. It makes sense to protect your house and yourself against anything that might cause significant damage."