The small study, which was published in the American Journal of Respiratory and Critical Care Medicine, determined that half of patients were still carriers of the virus even after symptoms resolved.
Researchers looked at 16 patients with mild cases who were admitted to the Treatment Center of PLA General Hospital in Beijing between Jan. 28 and Feb. 9.
“The most significant finding from our study is that half of the patients kept shedding the virus even after resolution of their symptoms,” co-author Dr. Lokesh Sharma from the Yale School of Medicine said in a statement.
On average, the patients still had the virus two-and-a-half days after no longer experiencing symptoms — but individual cases ranged up to eight days, the study said.
Researchers cited other studies in the report that found those carrying the virus could still be contagious to others. Given these findings, they warned that patients who have appeared to recover could spread the disease.
“This information can provide useful tool for clinicians and policymakers to ensure that recovered patients do not spread the virus,” researchers said.
The Centers for Disease Control and Prevention currently recommends that people with symptoms associated with coronavirus self-isolate for at least three days after the “resolution of a fever without fever-reducing medications.”
“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 two weeks after recovery to ensure that you don’t infect other people,” said co-author Dr. Lixin Xie of the Chinese PLA General Hospital in a statement.
The researchers, however, noted that more studies were necessary since the report was limited in scope. It’s unclear whether the same results would be found with an older group or among those with compromised immune systems.
“Our study is limited by the number of patients as there have been limited cases outside the epicenter of the coronavirus outbreak that has been successfully treated so far to be released from the hospital,” researchers wrote.