The Centers for Disease Control and Prevention (CDC) has made it possible for millions more Americans to get protection by extending eligibility for a COVID-19 vaccine booster shot.  Individuals in the following groups who received a Pfizer or Moderna vaccine are now eligible for a booster at six months or more after their initial shots, and the booster doesn’t have to match your original vaccine:

• 65 years and older
• Age 18+ who live in long-term care settings
• Age 18+ who have underlying medical conditions
• Age 18+ who work or live in high-risk settings

Boosters are also recommended for those age 18+ who received the Johnson & Johnson (J&J) vaccine two or more months ago.

Who Can Benefit Most from a Booster Shot?

People 65 or older, people aged 50 to 64 who have certain underlying health conditions, and those 18 or older who live or work in nursing homes, group homes, prisons, shelters, and other communal settings like schools are all at higher risk of contracting COVID-19. Immunocompromised people should also get an additional shot, not technically as a “booster,” but because data show they often don’t have an effective immune response in the first place. 

Outside the groups mentioned above, there’s generally less danger, says Dr. David Dowdy, an infectious disease epidemiologist at the Johns Hopkins Bloomberg School of Public Health. “For the vast majority of people, there’s not an immediate urgency to rush out and get this booster.”

How to Decide Whether or Not to Get a Booster

In addition to the factors of the immediate spaces in which you live and work, your decision concerning whether or not to get a booster can depend on, among other factors:

• How quickly the virus is spreading where you live 
• The types of safety measures local residents and businesses are taking 
• Your own overall health 
• Your personal sense of risk in light of your daily activities 
• The activities and health of others in your household 
• Your travel needs

If you feel your risk is high then, by all means, get the booster, says Dowdy, but there’s also a reason for waiting. The extra protection provided by the booster could serve you well at some point in the future when you find yourself at greater risk. “I fall into this category myself,” he says, “and I’m not in a rush to get a booster shot.”

Should I Be Concerned that My Vaccine Is Wearing Off?

The protection provided by the vaccine does wane somewhat over time, particularly under the onslaught of the fast-spreading delta variant. A CDC study of front-line workers found that the vaccines’ effectiveness at preventing infections dropped from 91% pre-delta to 66% once delta became dominant. There is no cause for panic, however. 

The vaccines never guaranteed prevention of contracting the virus, but were designed to minimize the severity of the impact in those who become infected. Dial Hewitt, an infectious disease physician at the Westchester County Department of Health in New York, confirms that the vaccines are working, saying, “We are not seeing a lot of reports of serious disease, hospitalization, or death.”

What about Reports of Declining Effectiveness?

A CDC study published in September listed the real-world effectiveness of the U.S. vaccines at preventing hospitalization as: Moderna at 93%, Pfizer at 88%, and J&J at 71%. While effectiveness at preventing hospitalization does appear to decline slightly, mostly in people 65 and over, infectious disease physician Jonathan Golob at the University of Michigan says it’s important to consider the context. 

Many older adults have other underlying conditions that can complicate the effects of COVID, particularly those who are severely immunocompromised. Even with the slight dip, he says, “The vaccines still remain excellent, even for older adults.”

Should I Match My Booster to My Vaccine or Switch It Up?

Experts are saying that, while scientific data on boosters is still limited, there are benefits to both matching your booster to your vaccine and to mixing it up. Getting the same booster can keep things simple, and an NIH study has found that following a Moderna vaccine with a Moderna booster leads to the highest antibody levels. Others may find it simpler to get a booster shot of whichever vaccine is available. Some reasons why you might want to purposely switch it up include:

• If you had bad side effects from your initial vaccine, you can now try a different one.
• Following a Moderna vaccine with a Pfizer booster could reduce side effects.
• Per an NIH study, following a J&J vaccine with a Moderna or Pfizer booster could produce a stronger immune response than a second dose of J&J. 

Ultimately, says Dowdy, the research is still very new, and “nobody knows what the actual level of protection is, longer term, for all of these different mix-and-match combinations.”

How Safe Are the Boosters?

There is very little risk to getting a booster, experts say. Though males aged 18 to 25 are at higher risk of myocarditis and pericarditis after an mRNA vaccine, studies show that cases are rare, and most patients feel better within six weeks. Women aged 18 to 49 account for most cases of TTS, a severe blood clot, following a J&J vaccine, though this, too, is rare. Fewer than 50 cases have been reported out of the 15 million J&J vaccine recipients in the U.S. 

Fortunately, you can choose the booster with which you are most comfortable. Younger men might consider J&J, and women aged 18 to 49 can get an mRNA option. If you feel uncomfortable getting a booster at all, says Angela Rasmussen, a virologist at the University of Saskatchewan, don’t fret. The vaccines are holding up well for those under 65 without underlying health problems, and the data suggests that “You really don’t need a booster.”

*Stone, W. (2021, Oct. 26). What You Need to Know About COVID Boosters. NPR. https://www.npr.org/sections/health-shots/2021/10/26/1049298884/covid-boosters-questions-help-science 

Much about the novel coronavirus, i.e., COVID-19, is still not fully understood. As research progresses and our knowledge of the virus increases, information can change rapidly. We strive to update all of our articles as quickly as possible, but there may occasionally be some lag between scientific developments and our revisions.