What to Know About the Updated 2024-2025 COVID Vaccines

[Originally published: Aug. 27, 2024. Updated: Oct. 24, 2024.]

Note: Information in this article was accurate at the time of original publication. Because information about COVID-19 changes rapidly, we encourage you to visit the websites of the Centers for Disease Control & Prevention (CDC), World Health Organization (WHO), and your state and local government for the latest information.

As the summer of 2024, marked by yet another COVID-19 surge, drew to a close, newly updated COVID vaccines became available for the fall and winter months, a time of year when respiratory illnesses can overwhelm hospitals. The new shots are expected to provide protection against severe illness, hospitalization, and death related to COVID.

The Centers for Disease Control and Prevention (CDC) recommends that everyone ages 6 months and older get one of the updated vaccines. Pfizer’s and Moderna’s updated mRNA vaccines were fully approved in the middle of August for everyone ages 12 and older, and each has a Food and Drug Administration (FDA) emergency use authorization (EUA) for infants and children ages 6 months through 11 years. The mRNA vaccines target a SARS-CoV-2 strain called KP.2.

The FDA authorized an updated COVID vaccine from Novavax later the same month for everyone 12 and older. That shot targets another strain—JN.1.

In October, the CDC made an additional recommendation that people 65 years and older, and those who are moderately or severely immunocompromised, receive a second dose of the vaccine six months after their first dose. The updated recommendation also allows for flexibility for additional doses (i.e., three or more) for people who are moderately or severely immunocompromised, in consultation with their health care provider.

Scott Roberts, MD, a Yale Medicine infectious diseases specialist, recommends the updated vaccines as the best way to protect against COVID infection and severe outcomes, including hospitalization and death. “COVID will never go away, and I am certain we are going to see an increase in cases in our communities this winter,” he says. “We’ve continued to see patients get admitted to the hospital with COVID, the majority of whom are unvaccinated.”

Below, Dr. Roberts answers questions about this fall’s updated COVID vaccines.

SARS-CoV-2, the virus that causes COVID, continues to mutate and spawn new strains, so it’s important to keep up with vaccinations that match the strain that is circulating as closely as possible, says Dr. Roberts. This is why new COVID shots are called “updated” vaccines as opposed to “boosters”—they are expected to be updated annually; boosters, by comparison, are additional doses of the same—or previous—formula taken to “boost” immunity.

The COVID vaccine updated in 2023 was aimed at XBB.1.5, an Omicron subvariant that had been the dominant SARS-CoV-2 variant in the U.S. and the world at that time.

The shots aren’t meant to prevent every SARS-CoV-2 infection; rather, the aim is to protect against severe illness, hospitalization, and death. They also restore and enhance protection from previous shots, which has declined over time.

Avoiding serious illness continues to be a major concern, because even though COVID infections have declined dramatically since the beginning of the pandemic, there have been periods of upticks in hospitalizations. In 2023, for instance, more than 916,300 people were hospitalized in the U.S. due to COVID, and more than 75,500 people died from it. What’s more, most people who were hospitalized had not received last year’s updated shot, according to CDC data.

Studies have shown that people who are 50 or older are more likely to get very sick than younger people—and those 65 and older have a higher than average risk for hospitalization and death due to COVID. Severe disease is also a higher risk for anyone who has a compromised immune system or a chronic medical condition, such as diabetes or heart disease. But some young, healthy people have developed severe illness from COVID as well.

In addition, vaccination reduces the chance of suffering the effects of Long COVID, according to the CDC. Long COVID refers to the wide range of symptoms and conditions, which may last for weeks, months, or even years, that some people experience four or more weeks after an initial COVID infection.

New strains have emerged already—a variant called KP.3.1.1 has been the dominant strain since August, accounting for 57.2% of cases in mid-October, followed by the XEC strain, which makes up 10.7% of cases, according to the CDC’s Nowcast, which provides model-based early estimates. Both have surpassed KP.3 (which overtook KP.2 earlier this summer). But Dr. Roberts expects the new shots will continue to help protect against severe illness even if the virus mutates and additional strains appear.

“Obviously, the more closely the strain and the vaccine match, the better,” he says. “But if there is a significant change that makes a new strain very different, I would still expect the planned vaccine to work.”

It’s worth noting that, for the new 2024-2025 shots, the FDA changed course from advising pharmaceutical companies in early June to focus on an updated vaccine aimed at the JN.1 variant to, later that month, recommending one aimed at the KP.2 variant, which had recently been gaining ground.

Dr. Roberts also points to the monovalent vaccine introduced for the fall and winter of 2023, which targeted the XBB.1.5 strain. After the rollout of that updated vaccine, JN.1 surfaced with more than 30 new mutations, he explains. “Many of us were nervous that the vaccine would not work on JN.1. However, in spite of the large genetic distance between the two strains, the vaccine still elicited neutralizing antibodies against JN.1, and it was effective,” Dr. Roberts says.

The COVID vaccines remain safe and effective, according to the CDC, which notes that hundreds of millions of people have gotten the shots at this point and that the COVID vaccines have received the most intense safety monitoring in U.S. history.

One concern has been myocarditis (an inflammation of the heart muscle) and pericarditis (inflammation of the lining outside the heart). In rare cases, these conditions have been observed after vaccination, mostly in adolescent and young adult males. But research has shown that cardiac complications, including myocarditis, were significantly higher after a COVID infection than vaccination for both males and females in all age groups.

“All vaccines have side effects. The important thing is to weigh the benefits of vaccination against the risk of side effects—and to do so from an individual and a population level,” Dr. Roberts says. “In most cases, especially with the COVID vaccine, the benefits of the protection against COVID continue to outweigh the risk of side effects from the vaccine.”

Anyone can report an adverse event related to a COVID vaccine on the government Vaccine Adverse Event Reporting System (VAERS) site.

It is safe to get COVID and flu shots at the same time, according to the CDC.

September and October remain the best times for most people to get a flu shot, and vaccination continues to be recommended while the flu virus circulates, typically from October through May.

There still isn’t data to say for sure whether combining a COVID shot with a respiratory syncytial virus (RSV) shot is the best strategy. RSV is an illness that causes mild cold symptoms in most people, but can lead to hospitalization and death in older people and babies. RSV vaccines were brand new in 2023 for older adults, and are recommended for anyone 75 and older or those 60 and older who are at high risk of severe RSV disease. A new RSV vaccine also became available last year for pregnant women (who can pass the antibodies along to their newborns).

The CDC recommends that everyone get one of the updated 2024-2025 vaccines, especially if they have never received a COVID vaccine, are 65 or older, are at high risk for severe COVID, are living in a long-term care facility, or are pregnant, breastfeeding, trying to get pregnant, or might become pregnant in the future.

If you had COVID recently, the CDC advises waiting three months after you recover before getting another shot.

According to the CDC, the vaccines are covered by insurance, including private insurance, Medicare plans, and Medicaid plans. Uninsured children also have access through the Vaccine for Children Program.

To find a location near you that carries the vaccine and to schedule an appointment, go to Vaccines.gov. You can also call 1-800-232-0233 (TTY 1-888-720-7489). Be aware that current distribution and insurance issues may delay the availability of the vaccines temporarily in some places.

Information provided in Yale Medicine articles is for general informational purposes only. No content in the articles should ever be used as a substitute for medical advice from your doctor or other qualified clinician. Always seek the individual advice of your health care provider with any questions you have regarding a medical condition.