Boosters Won't Protect You Against Omicron If You've Done This, Study Finds
A new study is calling into question the effectiveness of a third dose for some individuals.
The original Omicron variant took hold of the U.S. this past winter, sending COVID infections skyrocketing to record heights not seen before in the pandemic. And despite cases having fallen off significantly in February and March, a new subvariant of Omicron has pushed things back to a precarious place once more. According to the latest data from the Centers for the Disease Control and Prevention (CDC), coronavirus cases have increased by more than 25 percent in the last week alone, with nearly 70 percent of new infections the result of the BA.2 Omicron variant.
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As infections rise again in a time when most COVID restrictions and precautions have already been pulled back, virus experts continue to recommend two forms of protection: vaccinations and boosters. According to the CDC, more than 66 percent of the country's population has been fully vaccinated so far, but only 45 percent of these individuals have gotten an additional booster shot, despite it being heavily recommended by the agency.
"The protection COVID-19 vaccines provide decreases over time, especially for certain groups of people," the CDC explains. "Data show that an mRNA booster increases the immune response, which improves protection against getting a serious COVID-19 infection."
Now, new research is suggesting that your booster could be less beneficial against Omicron—depending on when you got it. An April 25 study released ahead of peer review on medRxiv looked at the effectiveness of primary and booster COVID vaccination against Omicron, and found less-than-ideal results for people who have already been infected with the virus.
For the study, researchers analyzed nearly 130,000 people tested for COVID in Connecticut from Nov. 2021 through Jan. 2022, which included around 10,000 people infected with Omicron and 6 to 8 percent infected with a prior variant of the virus. According to the researchers, two doses of an mRNA vaccine did provide protection against Omicron for anyone previously infected, but "we did not detect an additional benefit of receiving a third booster dose among this population," Margaret Lind, PhD, lead author of the study and a postdoctoral associate at Yale University, told Reuters.
A similar conclusion was gathered from a separate study out of Canada that was also released on medRxiv ahead of peer review. "Our findings showing that among previously-infected people, a third dose did not meaningfully improve the already-substantial two-dose protection against Omicron hospitalization," the researchers wrote in this study.
This does not mean that people with prior infections should not get vaccinated or receive a booster shot. The CDC notes that people who do not get their shots after already having had COVID are still more than twice as likely to be reinfected with the virus than those who got vaccinated after recovering from a prior infection.
"People should get two doses of mRNA vaccine regardless of if they have had a prior infection or not," Lind told Reuters.
In terms of a booster, the virus expert said that people who have not been previously infected with COVID should absolutely get the additional dose, while those who have had Omicron might also want one depending on other factors. "People with prior infections should consider a booster dose, especially if they are in a high risk group for life-threatening complications, but recognize that it may not provide significant additional protection against infection above two doses," Lind said.
You may also want to consider getting this third dose regardless, as other studies have suggested that the antibodies produced after vaccination are more protective for a longer period of time than those produced by natural infection, per The New York Times.
"I think that's the biggest argument to get boosted, frankly, even if you've had a recent infection," Amy Sherman, MD, an infectious disease physician at Brigham and Women's Hospital in Boston, told the newspaper. "It's a surefire way to give further protection and make sure your immune system produces peak responses."