While the Centers for Disease Control and Prevention (CDC) recommends a five-day isolation period, some people still test positive after five days or more. Are you still contagious then?
According to Joseph Bailey, MD, a pulmonary and critical care specialist at Northwestern Medicine, the infectious period for COVID-19 begins one to two days before symptom onset, and viral loads should peak around two to three days after.
“However, the exact period of time someone is contagious varies based on the severity of the COVID infection, vaccination status, and the person’s immune system,” Bailey told Verywell. “People with suppressed immune systems may be contagious for weeks or even longer.”
The CDC guidelines state that patients with mild to moderate COVID-19 are likely no longer infectious about 10 days after symptom onset. But people who are severely ill might have a longer infectious period, and the agency recommends extending the isolation period to at least 10 days and up to 20 days.
Omicron BA.5—the now dominant variant in the United States—can evade immune defenses and reinfect people more easily. But scientists are unsure whether the duration of viral shedding in BA.5 is longer than that of previous variants, Bailey said.
A small study suggested that 50% of the patients who tested positive five days after symptom onset were no longer infectious.
However, studies like these are mostly based on data from the original Omicron, as it is too soon for similar studies on BA.5 to be published, said John P. Mills, MD, associate professor of medicine at the Rutgers Robert Wood Johnson Medical School.
If you keep testing positive on a rapid antigen test—for instance, even 10 days after symptom onset—you should continue isolating until you no longer test positive, he said.
“I would say that a persistently positive antigen test suggests that one may potentially still be contagious, and that should inform one’s behavior,” Mills said.
When Can You Stop Isolating?
According to the CDC, people with mild, symptomatic COVID-19 can stop isolating five days after symptom onset, given that their symptoms have improved and they’ve been fever-free for at least 24 hours without the use of medications. Meanwhile, those with moderate COVID-19 must isolate for 10 days.
“Many experts believe patients with COVID should have a negative antigen test before exiting isolation, however, the CDC currently leaves that as an option but does not say it is necessary,” said Beth Oller, MD, a family physician at Solomon Valley Family Medicine.
The best practice is to continue limiting contact and wearing a well-fitting mask around other people for at least 10 days after symptom onset, Oller added.
“If you must interact with others before testing negative, make sure to wear a high-quality mask and maintain as much distance from others when you can, and avoid spending time in enclosed spaces with other people,” Oller said. “And since there are so many nuances to the guidelines, if you have questions, reach out to your family physician.”
The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.
