COVID-19 infections have continued to sicken people across the United States as new Omicron subvariants capable of escaping the immune system have become dominant. What worries experts is that protection against Omicron infections and hospitalization from the current vaccines decreases as people get older. Hence the recommendation for people to get booster shots.
The existing boosters have already proved effective. They significantly reduced severe disease from the original Omicron variant BA.1, which swept the country last winter. Now they are helping blunt disease severity seen with the new subvariants BA.4 and BA.5—although to a lesser extent, according to data shared at a June 28 independent committee meeting of the U.S. Food and Drug Administration.
That finding led the committee to vote in favor of including vaccine components that protect against Omicron variants in updated booster shots being developed for the fall. Following the committee’s recommendations, the FDA has now formally advised vaccine manufacturers that updated booster shots should contain components against BA.4 and BA.5 specifically, according to Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research. (Here’s why we need to be concerned about subvariants BA.4 and BA.5.)
It’s admittedly confusing when new recommendations come out every few months, but that is because scientists are learning about the virus in real time as new findings are published. “They’re basically just constantly trying to keep up with something that’s moving all of the time,” says Kawsar Talaat, an associate professor of epidemiology at the Johns Hopkins Bloomberg School of Public Health.
So what does all this mean for protecting yourself from severe COVID-19 infections right now? Do you need a second booster shot? Should you wait to get new boosters in the fall? What if a new variant arises before then? Here’s what top experts say you need to know.
Who can get a second booster shot?
The Centers for Disease Control and Prevention began recommending in March 2022 that people over 50 years old get a second mRNA booster shot—Pfizer or Moderna—if their previous booster was given at least four months earlier. The goal was to provide additional protection because the older people get, the faster their antibodies levels tend to decline, increasing their likelihood of severe disease and hospitalization with COVID-19 even after vaccination.
The CDC also recommended the second booster for those ages 12 and older with certain conditions that compromised the function of their immune systems. That group includes organ transplant recipients, those with untreated or advanced HIV, people receiving treatment for blood cancer, and those who have specific immunodeficiency diseases or who are taking immune-suppressing medications, such as steroids.
For those ages 50 and older, a second booster would be their fourth COVID-19 vaccine dose overall; for immune-compromised people, a second booster is their fifth dose, since the primary series for people with weakened immune systems is now three doses.
The Johnson & Johnson vaccine is the only non-mRNA shot approved in the U.S. People who took that single-dose shot and then got a J&J booster at least four months earlier were also advised to get an mRNA booster.
Why the limits on who should get a booster?
While the CDC lays out those who they consider eligible for a second booster shot, experts suggest there can be flexibility with the age and medical guidelines. Some people who meet the criteria may decide they don’t need a second booster just yet, while others who aren’t technically included in the recommendations may benefit.
“If they have a serious underlying illness, such as heart disease, lung disease, diabetes, and the like, that’s part of the judgment call,” says William Schaffner, a professor of preventive medicine and infectious disease at Vanderbilt University in Tennessee. People under age 50 with those conditions may want to talk to their doctor about whether it’s wise to go ahead and get the additional booster, Schaffner says. The same is true for those who may be working or living in a situation with a high risk of exposure.
Additionally, not all experts agree that boosters are necessary once people pass the somewhat arbitrary threshold of age 50.
“I just think this sort of blanket notion of everybody over 50 getting this vaccine doesn’t make sense,” says Paul Offit, a professor of pediatrics in the Division of Infectious Diseases at Children's Hospital of Philadelphia and one of two FDA advisory committee members who voted against including Omicron components in the fall boosters.
It makes more sense for people over age 70 because their less vigorous immune systems aren’t as good at stopping a mild infection from progressing to a moderate or severe one, Offit said. But at age 71 himself, Offit has only gotten his first booster. He feels that the single extra shot, along with the fact that he had a recent natural COVID-19 infection, offers about as much protection as possible because antibody levels fall so quickly after getting additional boosters.
Adults over 50 who have had an Omicron infection in the last six months already have more immunity from the infection than they’d get from another booster shot, based on data presented at the June 28 committee meeting.
Should I try and get a booster now, or wait for the fall?
By contrast, Johns Hopkins’ Talaat says to get the booster now if you qualify. “Don't wait for a better vaccine, because you leave yourself vulnerable,” Talaat says. “Get what boosters you're eligible for now, and then you will have the opportunity to get another booster that may provide broader protection in the fall.”
If you don’t have higher risk because of your age or medical condition, however, Talaat says that there’s no need to jump the gun when updated boosters are expected in October. “If you're under 50, you don't have any risk factors for severe disease, and you're not moderately or severely immunocompromised, if you are a healthy person and you have had your [first] booster, I would wait,” Talaat says.
Another reason to wait is that your actual risk of exposure may be greater in the fall, Offit says. Autumn means the start of school and people spending more time indoors, both of which will increase the risk of exposure and infection. The boost we get from another dose is fleeting—it begins waning within a month or two—so we might as well get it when we need it most, he says.
A lingering concern, though, is that it’s too early to say how effective updated boosters will be against whatever versions of the virus will be circulating at that time.
Boosters with an Omicron BA.1 component showed a 1.75 times increase in antibodies capable of neutralizing BA.1. But BA.1 isn’t circulating in the U.S. anymore, and the data shared with the FDA showed that these Omicron-containing boosters barely made a difference against BA.4 and BA.5 infections.
So is there going to be a variant-proof booster? Or will I need an annual shot?
It’s not currently possible to develop a “variant proof” booster because the virus is evolving so fast, Talaat says. Instead most experts, including Talaat and Schaffner, expect that COVID-19 boosters will eventually turn into an annual vaccination like the flu shot.
“We update that vaccine on an annual basis and recommend everybody receive their annual flu shot, and that provides the best possible protection, even though it’s not perfect,” Schaffner says. He added that scientists are working on a vaccine that combines the annual flu shot with an annual COVID-19 vaccine, but that’s at least a year or more away from becoming a reality.
For those who are immune-compromised and have the most reason to be concerned, Talaat reminded people that Evusheld—a monoclonal antibody drug used to prevent COVID-19—is more widely available now and is a good option for those who qualify and are concerned that vaccination may not offer enough protection.
Will the second booster reduce risks from long COVID?
A series of recent studies have yielded conflicting results on how much the current vaccines do—or don’t—protect against long COVID. Part of the reason for the confusion is the lack of a consensus on a clear definition of the phenomenon.
Some studies show that vaccines substantially reduce the risk of long COVID, while others show a more modest impact. Until researchers agree on a clear set of criteria for long COVID, it’s going to be difficult to get solid answers. But even if it’s not possible to quantify the effects, experts say vaccination likely offers some protection.
“It stands to reason that if you have a severe disease, you are more likely to develop long COVID than if you don't have a severe disease,” Offit says. “If you're fully vaccinated, I suspect you're much less likely to get long COVID because you're much less likely to get severe disease."