Coronavirus relapse: Wuhan patients test positive for the second time weeks after recovering
Wuhan has reported second-time infections of COVID 19, as many recovered patients retest positive for coronavirus. The city, which was the epicenter of the outbreak in China, was gearing up for a lift in the quarantine measures to allow the residents to venture out of their homes, come April. However, the relapse in COVID-19 cases is now posing serious questions about the diagnostic process for the disease and also hinting at a possible second wave of cases, said NPR.
Between March 18 and 22, no new cases of the deadly virus through domestic transmission (spread of the disease from person to person) were reported in Wuhan. This was a lauded achievement for the country for managing to contain the virus that has infected about 82,000 people in China, as of March 29. Wuhan was the worst affected region and comprised more than half of the total confirmed cases in the country.
New data shows that Wuhan residents who had previously tested positive and recovered from COVID-19 have tested positive a second time around. NPR said that many quarantine facilities in the city that have been observing recovered patients even after their discharge from hospitals have reported that about five to ten percent of patients deemed 'recovered' have tested positive yet again.
Some of the patients that retested positive for COVID-19 seem to be asymptomatic carriers (they carry the virus and can transfer it to others, but don't show any of the specified symptoms for the disease), which goes to show that Wuhan is far from being in the clear.
NPR sought out four contacts in the Chinese city through texts and phone calls, who responded in the affirmative. They said they have retested positive for coronavirus in March after they had been infected the first time and went through treatments to recover from it. They were released upon a clean bill of health after testing negative.
Among the four individuals that NPR contacted, two are front-line doctors who contracted the disease after treated infected patients in their Wuhan hospitals, and the other two are residents of the city. One of the residents told NPR that they had been hospitalized during their first time when they'd shown severe symptoms of the disease. The second resident showed milder symptoms and was quarantined in one of the makeshift centers that Wuhan had constructed as an emergency during the peak of the outbreak.
The two residents retested positive for coronavirus on March 22, even though they hadn't exhibited any typical symptoms for the disease when they sought medical care for unrelated health issues. The four residents tested positive the second time after weeks of recovering from the first diagnosis. While many Virologists say that patients re-contracting the disease is highly unlikely, it is also too soon to know if this could mean a second wave of the epidemic outbreak.
China announced that it will not include retested positive cases (after being released from health centers) in its overall daily count for new cases, in its new COVID-19 prevention guidelines, and neither will it include asymptomatic cases. "I have no idea why the authorities choose not to count [asymptomatic] cases in the official case count. I am baffled," one of the Wuhan doctors who tested positive for the second time after recovering said to NPR
These four individuals have been isolated and are under medical observation. It is yet to be confirmed if they are infectious and why they tested positive merely weeks after testing negative since they recovered from the first bout of the disease. There is also possible that the test that obtained negative results may have been false, which can happen when the swab used for ample collection misses bits of the virus. The same happened in the case of Dr Li Wenliang, who warned of the virus when it first broke out and died in February after getting infected amid treating patients. He'd tested negative for the virus several times before being diagnosed accurately.
Nucleic test acids used in China displayed accuracy identifying the positive coronavirus only about 30-50 percent of the time, Wang Chen, a director at the Chinese Academy of Medical Sciences estimated in February.
Another theory for the second time diagnosis is that residual virus from the initial infection had magnified in the tiny bits of DNA used in the testing.
In an email to NPR, Dr Jeffrey Shaman, a professor of environmental health sciences, Columbia University said, "There are false positives with these types of tests".
Shaman has co-written a modeling study that illustrates the transmission of the disease by asymptomatic individuals was what intensified the Wuhan outbreak.