Some People Recovered From Coronavirus Are Testing Positive Again: Why This May Happen
COVID-19 has spread across the world at an unprecedented rate, affecting several lives. Today it has infected over 150,000 and claiming lives of over 6000. But today, over 73,000 people (according to Here Maps COVID-19 tracker) have recovered from the novel coronavirus.
While this might sound like good new (and it surely is), reports around the world reveal that people around the world are contracting COVID-19, even after fully recovering and going home.
People are getting infected again
According to a SCMP report, a 36-year old Chinese man lost his life in Shanghai due to respiratory failure in Wuhan, five days after being discharged.
Osaka’s prefectural government on Wednesday revealed that a female tour bus guide who was first diagnosed in January recovered in a few days, but three weeks later she contracted COVID-19 for the second time.
Another man in Japan has shown case of contracting coronavirus again after being recovered, for the second time, according to an NHK report.
And there are several other cases that make us fear the worst. But why is this really happening?
Why are people getting infected again?
There is no definitive answer for this yet. Zhan Quingyuan, director of pneumonia prevention and treatment at the China-Japan Friendship Hospital in Beijing, Chinese National Health Commission briefing that while many COVID-19 patients are seen to create antibodies to fight against COVID-19 after getting infected, in some individuals the antibodies are not lasting as long as they should.
The Coronavirus can come once again into our body either through a relapse or if we get it from some other host. And the only way one can differentiate between the two is through a full viral sequence.
Today tests that detect COVID-19 presence are called RT-PCR (Real-time reverse transcriptase-polymerase chain reaction) that takes pieces of the virus’s genetic code, but not the whole thing. The test is designed to only take chunks that are unique to COVID-19.
According to Donald Burke, an international health expert at the University of Pittsburgh, in a conversation with Wired, theoretically, if doctors completely sequenced the virus in a patient’s nose or mouth swap, every time the test comes positive, they could compare the genetic letter with the help of genome reading software to determine if its the same strain of coronavirus or a new one. But there’s no way to surely know that.
Maybe it isn’t contagious anymore
Reported by CIDRAP, some researchers, however, feel that the presence of infection doesn’t really mean that it would be contagious. According to Stanley Perlman, MD, PhD, professor of Microbiology and Immunology at the University of Iowa, “Genomic material comes from virus, of course, but it does not indicate that infectious virus is present. Certainly (RT-PCR) is useful diagnostically; it is less useful for telling us whether someone is contagious.”
He added, “The patients may be patient carriers or they may just have viral genomic material without any infectious virus. It is hard to know—and hard to know if they are infectious as well. This is all murky at present.”
A similar thought is also shared by Florian Krammer, PhD, virologist and vaccinologist in the Department of Microbiology at the Icahn School of Medicine at Mount Sinai in New York City who tweeted that RNA of several kinds of viruses surface months after viral shedding has ended.
She said, “Follow-up tests can turn positive after a few negative tests, eg because sampling was better. Also, and this is a very important point, just because somebody still tests positive in a nuclei acid-based test does not mean they are still shedding infectious virus.”
Is there a solution to this problem?
As of now, the criteria involves normal temperature for at least three days, resolved respiratory symptoms, improvement in lesions on CT scans of the chest as well as negative RT-PCR tests, at least one day apart.
While all the studies are in nascent stages, researchers from a recent study in JAMA (involving one hospitalised patient and three home-quarantined, who were treated at Zhongnan Hospital in Wuhan University) has shed light on altering the current criteria where a hospital denotes a person fit for discharge, at least till we get access to vaccines to contain this entirely.