Positive Test Results for Recovered Patients
As China prepares to relax lockdown measures in Wuhan, the epicenter of the coronavirus outbreak, a new cause for concern has arisen. Some recovered COVID-19 patients are receiving positive test results for the virus a second time. (1)
The city of Wuhan houses recovered COVID-19 patients in quarantine centers after discharging them from the hospital. Data emerging from these centers shows that 5% to 10% of previously recovered patients are again testing positive for the virus. (1)
This raises the question of whether or not it’s possible to be reinfected by the coronavirus quickly after recovering from it. Virologists say that this is unlikely. But we don’t yet have enough information about the disease to know for sure. (1)
The culprit of these concerning results may be that the tests themselves have a high rate of inaccuracy. China has used nucleic acid tests to evaluate patients, and they are estimated to be accurate only 30% to 50% of the time. So, although a patient may have tested negative for COVID-19 and been discharged from the hospital, it’s possible that their test results were incorrect. (1)
And the inaccuracies don’t only extend to false negatives. “There are false positives with these types of tests,” Dr. Jeffrey Shaman told NPR. Dr. Shaman is a professor of environmental health sciences at Columbia University. He recently co-wrote a modeling study about how infected but asymptomatic people were one of the main causes of the early spread of coronavirus in Wuhan. (1)
China Not Counting Asymptomatic Cases
On Thursday, March 23, 2020, Wuhan officials announced that they had gone four days without any new cases of COVID-19. Many considered it a sign of hope that the tide of the disease was turning. (1)
But the independent Chinese news outlet Caixin was reporting something different. They learned from a health official that Wuhan hospitals continued to have positive test results for asymptomatic virus carriers. The health official said that he had seen up to twelve cases daily. (1)
When China shares its daily count for new and total coronavirus cases, it does not include asymptomatic ones. Nor do they include patients who test positive a second time after recovering. (1)
“I have no idea why the authorities choose not to count [asymptomatic] cases in the official case count. I am baffled,” said a Wuhan doctor who retested positive after recovering from COVID-19. The doctor asked to remain anonymous in his interview with NPR because the Chinese government has been detaining people who push back on how they have handled the coronavirus outbreak. (1)
Asymptomatic COVID-19 Carriers
When asymptomatic carriers in Wuhan test positive for coronavirus, they go to special facilities for a 14-day quarantine. If they develop symptoms during their quarantine period, the government adds their case to the daily counts. (1)
The Wuhan health commission shared their reasoning for not including asymptomatic positive patients in the daily case counts. “Based on available World Health Organization data, new infections are mainly transmitted by patients who have developed symptoms. Hence, [asymptomatic cases] may not be the main source of transmission,” the commission said, as reported by NPR. (1)
But this statement from the health commission is in direct opposition to research about the coronavirus outbreak in Wuhan and other Chinese cities. This research looked at patients who received COVID-19 diagnoses early in the outbreak. It shows that asymptomatic carriers can infect people that they’re in close contact with, like family members, contributing to the spread of the virus. (1, 2, 3, 4)
“In terms of those who retested positive, the official party line is that they have not been proven to be infectious. That is not the same as saying they are not infectious,” an anonymous Wuhan doctor told NPR. “If they really are not infectious, then there would be no need to take them back to the hospitals again.” (1)
Is China Ready to Lower Lockdowns?
Hubei province began allowing its residents to leave their cities on Wednesday, March 29, 2020. Wuhan, Hubei’s capital city, said that it would lift its quarantine restrictions and allow residents to leave starting on April 8, 2020. (1)
In order to leave Wuhan, residents will need to test negative for COVID-19. But because coronavirus tests result in so many false negatives, it’s possible that asymptomatic cases of the virus will slip through. The concern is that carriers of the virus, after testing negative for it, could further spread it after the lockdown measures are lifted. (1)
