Doctors in Wuhan have noticed a trend among a group of recovered COVID-19 patients: Between 3 and 10% of them test positive a second time, according to the South China Morning Post.

Wang Wei, who is the president of Tongji hospital, told China Central Television that doctors studied 147 recovered patients. Five of them, which is about 3%, tested positive for COVID-19 in nucleic acid tests after recovery.

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Quarantine facilities in Wuhan have reported between 5 and 10% of recovered patients testing positive again, Life Times reported.

Doctors are still trying to determine if recovered patients possess antibodies that would make them immune to the disease, and if they’re still able to infect people with the coronavirus that causes COVID-19.

Tongji doctors say they have found no evidence of the patients who again tested positive being infectious.


Wang said about 80 to 90% of similar patients had no trace of the virus in their blood a month after being discharged.

Wang said the sample size is too small to make a sweeping judgment about the new positive tests.

“These are just small samples and not enough to assure us of the validity of our initial findings,” Wang said. “We need a large-scale epidemiological study to guide our disease surveillance and prevention works.”

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Still, he said it’s crucial that patients with second positive tests be isolated until they can be tested again.

Tu Yuanchao, deputy director of Hubei health commission, told Hubei Daily that patients who tested positive again and are symptomatic would be readmitted to a hospital.

Asymptomatic patients are to be quarantined at at a facility for two weeks of observation, Yuanchao said.

RELATED: Asymptomatic individuals may be rapidly spreading COVID-19, according to researchers

Asymptomatic spread of the novel coronavirus has been a primary concern of global health officials as outbreaks explode in hot spots around the world, including the United States.

According to research from the National Institutes of Health, SARS-CoV-2, which causes COVID-19, and SARS-CoV-1, which caused the 2002 SARS outbreak that infected over 8,000 people, have a key difference that could explain why COVID-19 has become a much larger and seemingly more uncontrollable outbreak.

“Emerging evidence suggests that people infected with SARS-CoV-2 might be spreading virus without recognizing, or prior to recognizing, symptoms,” NIH researchers wrote.

The findings make control measures used for other known coronaviruses less effective against the new COVID-19 virus.

This story was reported from Atlanta.