How Long After Having COVID-19 Are You Contagious?

Learn what the official guidelines of quarantine and isolation are.

In the early months of the COVID-19 pandemic back in 2020, there were more questions than answers. One of these questions was: How long after someone has COVID-19 are they contagious?

Initially, the guidelines relied on what experts knew about viruses mixed with a little bit of trial and error since COVID-19 was a novel coronavirus (meaning it was a new strain that had not been previously identified in humans).

For example, in July 2020, epidemiologist Supriya Narasimhan, MD, from Santa Clara Valley Medical Center in California, told Health that an early paper out of China suggested sicker patients could be contagious for up to 21 days. And infectious disease expert Amesh A. Adalja, MD, senior scholar at the Johns Hopkins Center for Health Security in Maryland, told Health that someone who has had COVID-19 stopped being contagious approximately 10 days after symptom onset and after at least three fever-free days.

Some of this initial advice may have stemmed from the fact that after you've had COVID-19, it can still be detectable in the upper respiratory tract for up to three months, per the Centers for Disease Control and Prevention (CDC). But in September 2021, the CDC stated that you are "not likely infectious," despite it still being detectable.

If you've tested positive for COVID-19 or have symptoms of the virus, the advice from the CDC, as of March 2022, is clear: Don't leave your home unless you need medical care, and wear a well-fitting mask if you must be around others, even at home. But how long should you keep taking these precautions after you've recovered from COVID-19?

That depends on your symptoms and how long they're lasting, states the CDC. As of March 2022, the CDC recommends that if you've tested positive or have symptoms of COVID-19, regardless of your vaccination status, you should stay home for at least five days and isolate yourself from other people in your household. Wear a mask if you have to be around anyone during those first five days. You can end quarantine after five days if you haven't had a fever for at least 24 hours (without the use of fever-reducing medication, like ibuprofen or acetaminophen), and your symptoms are improving. For the next five days, you should wear a well-fitting mask around other people and continue to monitor your symptoms.

If you were asymptomatic but had a positive test, you can also end quarantine after five days. Just remember to wear a well-fitting mask for the next five days, and monitor any symptoms that may pop up.

And if you get very sick with COVID-19 or have a weakened immune system, the CDC recommends you isolate yourself for at least 10 days and talk to your doctor about when it's safe for you to end it.

"It is fair to say that sicker people will take longer to recover from their symptoms, and will need to stay isolated to prevent transmission to others for a longer time period until they have shown symptom improvement, as per the CDC recommendation," explained Dr. Narasimhan.

When you do go out in public or mix with other people after recovering from COVID-19, it's still important to take preventative measures to help reduce the spread of the virus. Wear a well-fitting mask for at least five days following your initial five days of quarantine, and as always, practice good hand hygiene.

Dr. Narasimhan stressed the importance of wearing a mask because it provides "source control." In other words, it helps prevent infectious particles that may come out of a person's mouth when they cough, sneeze or talk from getting into the surrounding airspace.

"It's important that all of us—including those who have recovered from COVID-19—maintain these safety precautions until we stop the spread of this pandemic," said Dr. Narasimhan.

The information in this story is accurate as of press time. However, as the situation surrounding COVID-19 continues to evolve, it's possible that some data have changed since publication. While Health is trying to keep our stories as up-to-date as possible, we also encourage readers to stay informed on news and recommendations for their own communities by using the CDC, WHO, and their local public health department as resources.

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