Can You Get COVID Twice?

Medically Reviewed by Zilpah Sheikh, MD on November 21, 2023
Written by Kim Painter
7 min read

If you’ve had COVID-19, you probably know the drill: the tests, the treatment choices, the days of social isolation and masking, and the concerns about whether you'll fully recover. Maybe you got vaccinated to lower your chances of going through all that again.

But now you have chills, a fever, a scratchy throat, and a runny nose. Could you have COVID-19 again?

It’s possible. Research shows you can get COVID-19 not just twice but multiple times.

COVID-19 reinfection and long COVID

A quick note: we're talking about getting COVID-19 and then getting it again. That's reinfection. Some people get COVID-19 and then have new, returning, or ongoing health problems for weeks, months, or years after their infection clears. That's something else, called long COVID.

But they are related in one way: research suggests that every time you get COVID-19, you face a new risk of getting long COVID. That's just one reason to care about whether you get COVID-19 again and again.

Here’s everything you need to know about COVID-19 reinfection.

 

Once you've had COVID-19, you get some protection against the virus. This protection tends to last several months, but it fades over time. In rare cases, people can get reinfected within just a few weeks.

Repeat infections usually are mild, but some people get very ill. Older adults and those with weak immune systems appear to be at an increased risk for a severe repeat illness. In general, your protection against severe symptoms lasts longer than your protection against a new infection. And any time you're infected, you can spread the virus to others.

Even if you stay up to date with COVID-19 vaccines, it’s possible to get reinfected and spread the virus. However, you're less likely to have serious symptoms or be hospitalized than people who haven't been fully vaccinated. When the coronavirus gets past your vaccine immunity, doctors call it a “breakthrough infection.”

You can thank your immune system for the partial protection you get naturally after a COVID-19 infection. This system springs into action whenever germs enter your body.

Here's how it works:

  • Bacteria and viruses (like the one that causes COVID-19) have proteins called antigens on their surfaces. Each type of germ has its own unique antigen.
  • White blood cells of your immune system make proteins called antibodies to fight the antigen. Antibodies attach to antigens the way a key fits into a lock, and they destroy the invading germ.
  • Once you've been exposed to a virus, your body makes memory cells. If you're exposed to that virus again, these cells recognize it. They tell your immune system to make new antibodies against it.

But the system isn't perfect. Viruses can mutate into new strains, making it harder for the immune system to recognize the invaders. And COVID-19 isn't the only virus you can get repeatedly. The length of protection varies from germ to germ. For example, influenza viruses mutate so much that scientists have to update flu vaccines every year.

Sharing your antibodies 

Since the early stages of the pandemic, researchers have hoped that people who recovered from COVID-19 could use their antibodies to help others, through something called convalescent plasma. Plasma is the liquid part of the blood. The idea is to give plasma rich in antibodies to people sick with the disease. But there's no firm evidence it helps. Some expert groups recommend trying it only in people who have poor immune systems. The World Health Organization says it should be used only for severely ill people in clinical studies.

You probably heard a lot about herd immunity in the early days of COVID-19. Herd immunity happens when a large part of the population, the herd, is immune to a virus. This can happen when many people get vaccinated or infected. Herd immunity makes it hard for a virus to spread. When the herd is well-protected, people who've never been sick or vaccinated are less likely to meet up with the virus. So are people who've already developed some immunity. Ideally, the virus peters out.

The size of the population that needs to be immune to create herd immunity differs. Some viruses are so contagious that they keep spreading even if just a small fraction of the population is vulnerable. That's the case with measles, for example. But herd immunity, created through vaccines, has worked for diseases including smallpox, polio, diphtheria, and rubella.

However, herd immunity for COVID-19 seems unlikely, despite early hopes. One reason is that COVID-19 continues to mutate, limiting protection from previous infections and vaccinations. Low vaccination rates make herd immunity even less likely.

Ever since the COVID-19 virus, SARS-CoV-2, began to infect people, it’s mutated and created variants. These mutations, or changes in the virus’s genes, can help it get past any defenses you've built up through infection or vaccination. Also, some variants have been more contagious, or easy to spread, than others.

For example, the Delta variant, which was widespread in early to mid-2021, was more contagious than earlier variants from 2020. And the Omicron variants, which first took hold in late 2021, have spread more easily than Delta or the original COVID-19 viruses.

Can you get Omicron twice?

Omicron variants have continued to evolve and dominate. If you got COVID-19 in 2022 or 2023, whether it was your first infection or not, it was most likely an Omicron variant. There's no reason to believe you can't get Omicron twice or more, but you probably won't know for sure. That's because standard COVID-19 tests don’t identify variants. Doctors usually assume you have one of the variants causing the most infections whenever you get sick.

Anyone can get COVID-19 more than once, but some are at a greater risk. They include:

Unvaccinated people. Studies find unvaccinated people are twice as likely as vaccinated people to get reinfected with COVID-19. The studies show that vaccines protect you longer than natural immunity.

Immunocompromised people. If you have a weak immune system, you’re more likely to get COVID-19 again, even if you’re vaccinated and you’ve had the virus before. That’s because the vaccine may not be as effective for you. If you are in this group, talk to your doctor about the best vaccine schedule for you.

To avoid getting COVID-19 again, follow the same steps that you can take to prevent it in the first place. You should:

  • Stay up to date with COVID-19 vaccines. Pay attention to public health messages about when to get your next dose. This is especially crucial for people with weak immune systems. If you have any questions about when to get vaccinated, talk to your doctor.
  • Improve ventilation. Keep the air moving in your home or workplace, as much as possible. To do that, you can open windows more often, use portable high-efficiency particulate air (HEPA) cleaners, and frequently change the filters on your heating and air conditioning system. Set your system's fan to “on” rather than “auto” to keep air circulating.
  • Move activities outdoors. COVID-19 spreads most easily in crowded indoor settings. So, it can help to move group activities outdoors, especially when there's a lot of COVID-19 in your community.
  • Avoid contact with infected people. If you know someone has COVID-19, it's best to stay away until they are less likely to spread the virus, which is at least 5 days under CDC guidelines. If that's not possible, wear a mask, frequently wash your hands, and try to improve airflow.

If there are a lot of people infected with COVID-19 in your area or you are at high risk for COVID complications, you can get extra protection by:

  •  Wearing a high-quality mask or respirator, such as an N-95 model. It should fit closely over your mouth and nose.
  • Avoiding crowds and keeping some distance between yourself and others in public.

Right now, there's no reliable test that can tell you if you are immune to a new COVID-19 infection. You might think that antibody tests would fit that bill. But they don't.

It's true that you can get a test that tells you whether you have antibodies to the virus, because of vaccination or a previous infection. (One thing to know: it can take days to weeks after infection for antibodies to show up on these tests.)

But antibody tests can't tell you whether you have immunity, whether a vaccine worked, or when you need another vaccine dose, according to the U.S. FDA. For one thing, your immune system doesn't rely on antibodies alone to fight infection. Also, the tests might miss the kind of antibodies created by vaccination.

The tests have some uses: For example, some people with COVID-19 complications might need these tests to confirm they had the virus. Also, scientists can use them to estimate levels of COVID-19 immunity in a community.