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What to expect if you get a breakthrough COVID-19 infection

What are the symptoms? How sick can you expect to get? What should you do? Here's what you need to know.

What you need to know about breakthrough infections.
What you need to know about breakthrough infections.Read moreCynthia Greer

Getting vaccinated is the best way to slow the spread of COVID-19 and to prevent infection by delta and other variants. And as of Sept. 13, more than 178 million people in the U.S. have been vaccinated against the virus. As we all know though, COVID-19 is still alive and thriving, and the delta variant remains a major problem nationwide.

While the majority of people who are getting sick are unvaccinated, some people who are fully vaccinated are getting infected, too — a situation referred to as a “breakthrough infection.”

“We are seeing some breakthrough infections, but they are still very rare, and the most important thing is that this does not mean the vaccine didn’t work,” says Neal Goldstein, an assistant research professor of epidemiology and biostatistics at Drexel University. “If you recover and never had to go to the hospital, that is the vaccine working. That’s exactly what the vaccine is supposed to do — it’s supposed to save your life, and the folks that we’re seeing filling up hospitals are really the unvaccinated.”

Studies suggest that if you’re vaccinated, you’re eight times less likely to be infected with COVID-19, and 25 times less likely to be hospitalized or die. But given no vaccine is 100% effective, there’s still the chance of getting sick. Wondering what to expect if it happens to you? Here’s what you need to know if you’re vaccinated and get COVID-19.

» READ MORE: What are the symptoms of breakthrough COVID-19? And did I have it?

How sick will I get with a breakthrough infection?

No one likes to get sick. But here’s the good news: If you’re vaccinated, you’re significantly less likely to get severely ill if you get COVID-19. You might not experience any symptoms at all. If you do, your symptoms are likely to be milder than if you hadn’t been vaccinated, says the CDC.

“Everybody is a little different. It can range from you being asymptomatic to feeling pretty lousy, but typically it’s a shorter course than what we’re seeing for COVID without the vaccine,” says Meenakshi Bewtra, a Penn Medicine physician and an assistant professor of epidemiology and medicine at the University of Pennsylvania. “A friend I know got a breakthrough case, and he had one of the worst sore throats he ever had. But that lousy feeling typically goes away in less than a week.”

You might feel like you have a little sore throat and a runny nose and not initially realize you have COVID-19. Or you could feel similar to if you had the flu. COVID-19 symptoms like losing your taste and smell can also happen with breakthrough infections. But rarely do vaccinated people get very sick and die.

In a study published in June involving health-care workers and other frontline workers, vaccinated participants had a 58% lower risk of fever and reported two fewer days sick in bed after getting infected. Bewtra says those at highest risk of developing severe illness from a breakthrough infection are people who are immunosuppressed. “Usually these are folks who have underlying medical issues that may have prevented them from responding to the two-dose vaccine series appropriately,” she notes.

What should I do if I get a breakthrough infection?

Although your risk of getting infected after vaccination is low, if you have symptoms that are consistent with COVID-19, you should isolate yourself from others and get tested, says the CDC. Preliminary evidence suggests that fully vaccinated people can spread the virus if infected with the delta variant. And this means precautionary measures remain important. These include both testing and masking up in indoor public places where there’s substantial or high COVID-19 transmission.

If you’re not experiencing any symptoms, you don’t need to get tested unless you’ve come into close contact with someone with suspected or confirmed COVID-19. If this happens, get tested three to five days after exposure and wear a mask in public indoor settings for 14 days or until you receive a negative test result.

What if you have a mild cough and you’re not sure if you need a test? Reach out to your doctor, who can help you make that call.

“Part of it is, what have you been doing and where have you been — if you’ve been in an indoor setting with folks who you’re not sure of their vaccination status and there wasn’t mask-wearing, like indoor dining, concerts, and other venues, even a mild symptom would warrant getting tested,” says Bewtra.

You should also call your doctor if you test positive, and you’ll need to isolate at home for 10 days. You’ll want to call anyone you’ve recently seen or anywhere you’ve been in close contact with people, such as your workplace, too, says Bewtra.

» READ MORE: Where to get a COVID-19 test in the Philly region

Will I get ‘long COVID’ with a breakthrough infection?

Some people who get infected develop symptoms that last weeks or months, a situation that’s been coined “long COVID.” Symptoms range from brain fog to persistent fatigue to extended loss of smell or taste to numbness to shortness of breath. This can happen to anyone who has had COVID-19, even if the illness was mild, and unfortunately, even if you’re vaccinated.

Just how common it is for vaccinated people to develop long COVID, however, is still being researched. “This is an emerging area, and we’re still learning about whether folks who are vaccinated develop lingering symptoms, if they last as long, and if they are as severe,” says Bewtra.

Recently, a British study of more than 1.2 million people found that the odds of having symptoms for 28 days or more were approximately cut in half for vaccinated participants vs. unvaccinated participants. Although the reasons for long COVID remain largely unknown, experts say your best defense against COVID-19, and, in turn, long COVID, remains getting vaccinated.

“Indoor settings, yes, I’m still being cautious, but I would not put it on my top 10 list of things I’m worrying about right now,” says Goldstein.

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  1. Meenakshi Bewtra, MD, MPH, is a Penn Medicine physician and an assistant professor of epidemiology and medicine at the University of Pennsylvania.

  2. Neal Goldstein, Ph.D., MBI, is an assistant research professor of epidemiology and biostatistics at Drexel University.