Why You Might Need Two COVID-19 Shots This Season

Seniors and people who are immunocompromised should get not just one but two COVID-19 shots this respiratory virus season. That's the new recommendation from the U.S. Centers for Disease Control and Prevention (CDC).

People in these groups should get the vaccines six months apart in order to stay protected against the disease, the agency's vaccine group recently agreed.

Here's what to know about the new advice.

Why the need for more than one shot this season?

The recommendation follows a summer COVID-19 surge that led to more hospitalizations among the most vulnerable Americans. While rates are currently low, health experts are concerned they could spike again during the holiday season, when people travel more and gather in larger groups. The guidance went a step further for people who are immunocompromised due to conditions like cancer; they can receive three or more doses during this respiratory disease season, depending on how weakened their immune systems are and their potential exposure to environments where COVID-19 might be circulating.

“What we have seen over time is that as more and more of the population has immunity, the most vulnerable individuals are starting to narrow down,” says Dr. Yvonne Maldonado, professor of global health and infectious diseases at Stanford University and a member of the committee that advised the CDC on the decision. “We know at this point that 70% of hospitalizations now in the U.S. for COVID-19 are among people 65 and older, and that 50% occur in those 75 and older. So if we address COVID in those populations, we are looking at potentially reducing 70% of the risk of hospitalization from the disease in this country right now.”

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Data also show that immunity generated by the vaccines wanes after four to six months, so the additional dose should help to keep older people protected throughout the year—through not just the fall surge, but also through the additional peaks that have been occurring with COVID-19. “We are still waiting to learn the pattern of this disease,” says Maldonado. “COVID-19 seems to have two peaks a year, but they are not well characterized yet since the virus hasn’t been around very long. Giving a second dose gives people the opportunity to not spend so much time worrying about coverage.”

Does the updated shot work?

The current mRNA vaccines from Moderna and Pfizer-BioNTech target the KP.2 variant, and the Novavax vaccine targets the JN.1 variant—neither of which are the dominant version causing infections in the U.S. right now. According to the latest CDC estimates, the KP.3.1.1 variant is causing nearly 60% of new COVID-19 infections, and the XEC strain is rapidly becoming more common, responsible for 10% of new infections. Those variants appear to spread more easily among people, although there isn't any evidence yet that they could lead to more serious disease. That's why boosting immunity with another dose for those most vulnerable to COVID-19 complications could protect them as their chances of getting infected potentially increase.

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The KP.2 and JN.1 variants are still related to KP.3.1.1, since all of them are Omicron subvariants, so the vaccines should still provide sufficient protection from severe disease, says Dr. Steven Furr, board chair of the American Academy of Family Physicians. “I tell [my patients] that the vaccine does decrease hospitalizations and risk of death,” he says. “They still might get COVID, but they are much less likely to get it if they are vaccinated—and if they do get it, it’s less likely to be severe.”

That’s especially true for older people and people with weaker immune systems. “If you are diabetic, or hypertensive and have multiple problems, COVID could be enough to tip you over to getting pneumonia, getting really sick and dehydrated," Furr says. "It only takes one illness to tip your body over to more morbidity and mortality.”

The need for adequate supply

Vaccination rates are still relatively low. But seeing friends or family get infected remains one of the strongest motivators, says Furr—and he believes the uptick during the summer is encouraging people to ask for COVID-19 shots when they get their flu shot. For family physicians, though, getting enough doses to meet that demand has been a struggle. For his practice in Jackson, Ala., Furr ordered 100 doses weeks ago, and they've trickled in slowly. “We used up those first 20 doses in two days,” he says. “We’re told the distributors don’t have them or they are on backorder. I don’t know if they are prioritizing other groups, but it’s been a real frustration with the last two iterations of the COVID-19 vaccine to get enough supply to meet the need.”

Furr says it’s important to ensure that family doctors have enough supply. “People who are on the fence and aren’t begging to get the shot are not likely to go to the pharmacy,” he says. “They’re going to walk into their family physician’s office where during a wellness visit or a diabetic exam they can talk through the vaccine with their doctor.”

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Those conversations are also critical for helping people understand what the vaccines can and cannot do. “The point of [vaccination] has never been to stop all infections,” says Maldonado. “We’ve never had the aim of stopping transmission and all infections. The idea was to stop hospitalizations and stop deaths.”

Allowing for additional COVID-19 vaccine doses “allows people to make the best decisions possible to keep themselves and their loved ones safe from COVID-19,” CDC director Dr. Mandy Cohen said in a statement. “CDC will continue to educate the public on how and when to get their updated vaccinations so they can risk less severe illness and do more of what they love.”