Study Finds COVID-19 Can Persist After Symptoms Disappear


The length of time patients remained contagious after the end of their symptoms, however, ranged from 1 to 8 days.

Researchers have found that approximately half of their patients treated for mild cases of the novel coronavirus (COVID-19) still had the virus for up to 8 days after their symptoms disappeared, according to a research letter published in the American Journal of Respiratory and Critical Care Medicine.

The study included 16 patients with COVID-19 who were successfully treated in a Beijing hospital between January 28 and February 9, 2020. The patients had a median age of 35.5 years. The patients were discharged after confirmation of negative viral status by at least 2 consecutive polymerase chain reaction tests.

The patients’ primary symptoms included fever, cough, pharyngalgia, and dyspnea. They were treated with a range of medications. The incubation period was 5 days for all but 1 patient, and the average duration of symptoms was 8 days. The length of time patients remained contagious after the end of their symptoms, however, ranged from 1 to 8 days.

“The most significant finding from our study is that half of the patients kept shedding the virus even after resolution of their symptoms,” said co-lead author Lokesh Sharma, PhD, in a statement.

Sharma added that more severe infections may result in longer shedding times, but the authors said more research is needed to confirm this theory. All of the included patients had mild infections and recovered fully. Furthermore, they added that it is unclear whether their results would be consistent in more vulnerable populations such as the elderly and immunosuppressed.

Their findings, if confirmed in broader studies, could result in updated recommendations for quarantine periods as well as recommendations for handling asymptomatic patients.

“If you had mild respiratory symptoms from COVID-19 and were staying at home so as not to infect people, extend your quarantine for another 2 weeks after recovery to ensure that you don’t infect other people, said corresponding author Lixin Xie, MD, in the statement.

The authors also urged medical professionals to exercise caution when interacting with asymptomatic or recently recovered patients, and to treat them as carefully as those who are symptomatic.


Some COVID-19 Patients Still Have Coronavirus After Symptoms Disappear [news release]. American Thoracic Society; March 27, 2020. Accessed March 31, 2020.

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