Getting the flu shot has become an annual tradition for many of us and provides annual protection against a virus that has killed an estimated 12,000 to 61,000 Americans each year since 2010, according to the CDC. Annual shoots are the norm for influenza, but for other dangerous diseases, such as measles, only one or two shoots can provide lifelong protection. The big question in 2021: where does the COVID-19 vaccine fall? Will one or two doses (Pfizer and Moderna require two shots every few weeks) be enough to last a lifetime or at least several years? Or will COVID-19 become the “new flu shot” that requires a dose every year?

Do I need a COVID-19 vaccine every year?

Pfizer CEO Albert Bourla said in April that we probably “need a vaccine booster shot within six to 12 months,” and from there there will be an annual re-vaccination, but all of that needs to be confirmed. “He noted that depending on how quickly and effectively the virus can mutate, which experts agree is one of the key factors in determining whether we need an annual shot. The other? How long does immunity last.

How long does COVID-19 immunity last after vaccination?

Right now, vaccines appear to trigger an immune response that lasts longer than natural infection, according to Andrew Pavia, MD, an infectious disease specialist at the University of Utah Health, in an interview with Rochester first. That means the vaccine provides immunity “may last longer than a year,” he said, “but it is unlikely that it will be permanent, as two doses of measles vaccine are.” Dr. Pavia said it is likely that “at some point” we will need to receive another COVID-19 vaccine; we do not know exactly when or how often. There is just not enough data yet to know exactly how long the immunity lasts.

But researchers are already working to answer this question. According to New York Times, researchers are likely to track down vaccinated people to see who comes down with COVID-19, even after receiving a vaccination. Both the Pfizer and Moderna vaccines are over 94 percent effective in preventing COVID-19, and Johnson & Johnson are 66 percent effective, meaning that some “breakthrough cases” are possible no matter what vaccine you receive. If vaccinated people start to get sick, it is a sign that the protection is getting weaker, which tells researchers about how long the vaccine remains effective. Researchers will also monitor the level of antibodies and T cells in the blood of vaccinated people to see if and when a new shot is required.

Are COVID-19 vaccines effective against new variations?

Potential mutations are also a factor in whether we need follow-up vaccinations, and we know that SARS-CoV-2 (the virus that causes COVID-19) has already begun to mutate. While the current vaccines appear to be effective against strains from the UK and South Africa, Drs. Pavia that the virus is likely to continue to mutate, potentially making it more resistant to the vaccines we have. According to the CDC, current data show that the Pfizer, Moderna, and Johnson & Johnson vaccines “offer protection against most variants. However, some variants can cause disease in some people after they are fully vaccinated.”

As the virus continues to mutate, “we will have to adapt the vaccine just as we do with the flu vaccine,” said Dr. Pavia.

Although the United States has been distributing the COVID-19 vaccines since December, this is a reminder that we still have much to learn about their long-term effectiveness. As research continues to come in, it looks like we’ll have to get vaccinated again at some point – we’m just waiting to find out when. Meanwhile, and as Americans continue to be vaccinated, it is important to continue to do what we can to protect ourselves and others: wash your hands often and for at least 20 seconds, stay away from crowds and indoor events, and wearing a face mask in public if you are not fully vaccinated.

POPSUGAR aims to provide you with the most accurate and up-to-date information on coronavirus, but details and recommendations regarding this pandemic may have changed since its publication. For the latest information on COVID-19, please see resources from WHO, CDC and local public health departments.