The Food and Drug Administration (FDA) issued an emergency use authorization (EUA) last week for the Pfizer-BioNTech vaccine.
Cases of reinfection with the virus that causes COVID-19 have been reported.
Even if you’ve developed COVID-19, getting the vaccine may help prevent reinfection and lower your risk of getting sick again.

COVID-19 is currently the leading cause of deathTrusted Source in the United States — killing more people each day than heart disease or cancer.

To help stem the tide of this life-threatening disease, scientists around the world have been working to develop vaccines.

Last week, the Food and Drug Administration (FDA)Trusted Source issued an emergency use authorization (EUA) for the first of these vaccines, developed by Pfizer and BioNTech.

The EUA allows for the distribution of the Pfizer-BioNTech COVID-19 vaccine across the United States. This vaccine has been developed to prevent COVID-19 in people age 16 years and older.

Getting 2 doses of the vaccine may drastically reduce your chances of developing COVID-19.

Even if you’ve had COVID-19, getting the vaccine may help prevent reinfection and lower your risk of getting sick again.

“We’re really happy to have a safe and effective tool [against COVID-19],” Dr. Iahn Gonsenhauser, chief quality and patient safety officer at The Ohio State University Wexner Medical Center in Columbus, Ohio, told Healthline.

“We’re encouraging everybody to explore their opportunity to access the COVID vaccine as soon as that’s made available to them,” he said.
Natural immunity may wane

When someone develops COVID-19, their immune system learns to recognize the virus and begins to produce antibodies to fight against it.

If that person recovers from the disease, they may have immunity against reinfection with the virus for a period of time afterwards.

However, questions remain about how long that immunity lasts.

“We don’t know how long the immunity triggered by infection persists, and someone infected in the spring may no longer be immunologically protected now in December,” Dr. David Hirschwerk, an infectious disease specialist at Northwell Health in Manhasset, New York, told Healthline.

“It does stand to reason that somebody with COVID-19 infection is likely immune for 3 to 4 months at least,” he said, “but we don’t have firm data to support this yet.”

Cases of reinfection with the virus that causes COVID-19 have been reported.

Vaccination may raise immunity

Getting vaccinated may help to strengthen immunity against COVID-19.

In an ongoing clinical trial, Pfizer and BioNTech have studied their vaccine in people with and without a history of exposure to the virus.

Their research to date has found the vaccine is 95 percent effective at preventing COVID-19.

Their findings suggest it may help prevent reinfection in people who have already been exposed to the virus, as well as lowering the risk of infection in people with no history of exposure.

“Data from the phase 2/3 trial for the Pfizer-BioNTech vaccine suggest that the vaccine is safe and likely effective in persons with previous evidence of SARS-CoV-2 infection,” said Dr. Miriam Smith, chief of infectious disease at Long Island Jewish Forest Hills in Queens, New York.

“[The] vaccine should be offered to all persons regardless of history of prior symptomatic or asymptomatic infection,” she said.

The Centers for Disease Control and Prevention (CDC)Trusted Source currently advises that people with a known history of COVID-19 may wait up to nearly 90 days after their prior infection to get vaccinated, if they prefer to do so.

While more research is needed, available evidence suggests that reinfection with this virus is rare within 90 days of initial infection.

If someone currently has active symptoms of COVID-19, the CDC recommends they wait to get vaccinated until they’ve recovered and met the criteriaTrusted Source for ending isolation.

Weighing the benefits and risks

The Pfizer-BioNTech COVID-19 vaccine carries some risk of side effects.

However, ongoing research suggests the side effects tend to be mild and short-lived.

“The way that we generally approach these questions in healthcare is through risk-benefit analysis,” Gonsenhauser said.

“In this case, the risk of some adverse response to the vaccine is low, and the benefit of knowing that you have a potentially extended or refreshed immunity to COVID is significant,” he said.

“With that, we’re recommending that people get the vaccine, even if they’ve already had a COVID exposure and infection,” he continued.

The most commonly reported side effect associated with the Pfizer-BioNTech COVID-19 vaccine is pain around the injection site.

Some people who received the vaccine developed other side effects such as fatigue, headache, and muscle aches, which tend to resolve within a day or so.

The risk of severe adverse events following the vaccine appears to be very low. However, some groups of people might face higher risk of adverse reactions than others.

For example, if you have a history of severe allergic reaction to any of the ingredients contained in the vaccine, the FDATrusted Source recommends that you not receive it.

Talk with your doctor to learn more about the potential benefits and risks of getting vaccinated against COVID-19.