MIT Medical answers your COVID-19 questions. Got a question about COVID-19? Send it to us at CovidQ@mit.edu, and we’ll do our best to provide an answer.
I just found out that the friend I spent time with over the weekend tested positive for COVID-19 on Monday afternoon. I’ve been told to quarantine for 14 days.* When should I be tested? And if the test is negative, can I end my quarantine early?
We generally recommend that individuals be tested no earlier than five to seven days after a possible exposure. Research has shown that people who become ill develop symptoms, on average, between five and six days after becoming infected. This is about the same amount of time it takes for a PCR diagnostic test to be more likely than not to return a true-positive result, even if an individual doesn’t have symptoms. Researchers have estimated that as many as 40–45 percent of individuals who are infected with the SARS-CoV-2 virus never develop noticeable symptoms but are still able to spread the virus to others.
But while a negative test result may help to put your mind at ease, it does not end your quarantine period early. Since the incubation period for the virus can be as long as 14 days, a negative test result during that possible incubation period is no guarantee that you are not infected. It means only that, at the time of your test, your sample did not — or did not yet — show viral levels high enough to be reliably measured.
While quarantining, you should be actively monitoring yourself for symptoms of COVID-19, especially any change in your sense of smell or taste, one of the most common and predictive symptoms of the virus. Although the average person who becomes ill with COVID-19 begins showing symptoms a little more than five days in, 25 percent won’t become ill until more than a week has passed. And one large meta-analysis of observational data found that approximately five percent of infected individuals do not show symptoms until nearly 12 days post-exposure.
Unfortunately, if you develop symptoms, the clock gets reset. At that point, you will need to self-isolate for 10 days from the date of your first symptom(s) or until you’ve been fever free for 24 hours, whichever is longer.
But as long as you don’t develop symptoms, you’re free to resume your normal life once those 14 days have passed. Just make sure your normal life includes normal coronavirus precautions, like wearing a mask, keeping your distance, and avoiding spending prolonged periods of time indoors with people outside of your “bubble.”
There’s no way around it; quarantine is tough. Fourteen days cooped up with a thermometer and a Netflix account is nobody’s ideal staycation. But it’s one of those sacrifices we all need to make to keep viral spread under control. We hope that you remain symptom free and that what’s left of those two weeks flies by for you quickly.