• This story is regularly updated for relevance. Last updated: Aug. 5, 2021

Multiple COVID-19 vaccines have been rolled out across the country, but with news of new, more contagious strains spreading, many potential recipients are wondering how long the COVID-19 vaccines will keep the inoculated safe from being infected with the coronavirus.

It is not yet known precisely how long the vaccines will remain effective, though you should be immune for an absolute minimum of six months. On April 1, Pfizer said its version lasts at least a half-year, and Dr. Susan Bailey, the president of the American Medical Association, told Healthline, “But it’s definitely longer than that—it’s not just going to drop off after 6 months. I would have been concerned if efficacy had dropped by a third or half.”

Pfizer, though, said in April that it’s possible people might need a booster at some point, possibly within a year of originally getting vaccinated. People then perhaps might need to get an annual vaccine shot.

Based on other vaccines for viruses similar to the novel coronavirus, however, the COVID-19 vaccines could last for at least a few years. The chief executive of Moderna confirmed this on Jan. 7, noting that Moderna’s COVID-19 vaccine is expected to protect against the coronavirus for “at least a couple of years.” 

By mid-July 2021, though, Pfizer and the U.S. government were engaging in a debate about whether a booster needed to be introduced, especially since preliminary data has shown the vaccine might start to wane after 6-8 months.

In early April, Moderna confirmed that, like Pfizer, studies showed the vaccine was good for at least six months (in early August, Moderna said it was still 93% effective six months after you receive the second shot). Meanwhile, Johnson & Johnson said its vaccine has been shown to last at least eight months.

“The nightmare scenario that was described in the media in the spring with a vaccine only working a month or two is, I think, out of the window,” Moderna CEO Stephane Bancel said. “The antibody decay generated by the vaccine in humans goes down very slowly … We believe there will be protection potentially for a couple of years.”

But some experts believe that people will need to receive vaccine boosters to keep the virus at bay. “We have to appreciate that we were always going to have to have booster doses; immunity to coronavirus doesn’t last forever,” Sharon Peacock, who heads up COVID-19 Genomics UK, told Reuters in March 2021.

Immunity for elderly patients may not last as long, due to their immune systems typically being less healthy than younger patients.

It is currently also unknown how long naturally acquired immunity from COVID-19 lasts. Reinfection is possible in as little as under a year, so the Centers for Disease Control and Prevention recommends that even those who have already suffered a case of COVID-19 still get vaccinated.

Moderna is in the process of proving its vaccine to be equally as effective against the new variant of COVID-19, according to Bancel. This new strain appears to be more contagious, but experts believe the vaccines will work just as well against it. 

In mid-March, it was revealed that Pfizer showed 94% effectiveness against asymptomatic transmission of COVID-19 and 97% effectiveness against symptomatic transmission. And Pfizer, which is now available for kids aged 12-15, keeps on showing that its vaccine works against variants, even the delta variant that has begun to spread across the world.

All of which means that this version of the vaccine keeps you safe and is effective in stopping you from spreading the virus to anybody else.

Read more on the coronavirus vaccines:

• When will COVID-19 vaccines get full FDA approval? And what will that mean?
• How to convince someone to get vaccinated
• Can the COVID vaccine alter your DNA?
• What happens to all the unused COVID vaccines?
• Can the COVID vaccine give you herpes?
• All U.S. adults now eligible for COVID-19 vaccine, but some are still holding out
• Will you need a COVID-19 booster shot? And an annual vaccine?
• If you got the COVID vaccine but didn’t experience any side effects, is it still working?
• Which COVID vaccine is the best?
• How long will the COVID-19 vaccines keep you safe from the coronavirus?
• Can you drink alcohol after getting the coronavirus vaccine?

Sources: Reuters, WebMD, CBS News, CDC

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