Researchers suggest that common testing methods would not detect all traces of the virus (Photo by Xinhua News Agency)
A Chinese study published in monthly peer-reviewed scientific journal Cell Research on Tuesday has found that COVID-19 patients discharged from the hospital could still carry the virus deep in their lungs, which is undetected by conventional testing methods. This could explain why a growing number of recovered patients had tested positive again.
The study was based on the postmortem examination of a 78-year-old woman who died after having had the coronavirus. She was admitted to Three Gorges Central Hospital in Chongqing on January 27 after a fall. She then also tested positive for the virus and developed its symptoms. After receiving antiviral treatment, she was deemed ready to be discharged on February 13, having returned negative results in three rounds of testing, and her condition had improved significantly, backed up by a CT scan. However, one day later, she suffered cardiac arrest and died.
The postmortem of the woman found no trace of the coronavirus in her liver, heart, intestine, skin or bone marrow. But the researchers found complete strains of the virus in tissue deep in her lungs. They put tissue samples under an electron microscope to confirm the existence of the intact coronavirus enveloped in a crown-like shell.
The lung tissue featured the damage typically caused by a viral infection, but the absence of the virus in the rest of the body made detection difficult because the testing methods in mass use do not retrieve samples from deep in the lungs.
The research team suggested flushing the lungs of patients before they are discharged from the hospital, for more accurate detection of hidden strains. This diagnostic procedure involves inserting a tube containing a washing fluid into the lungs via a patient’s mouth, which is more complex, time-consuming and costly than a nose or oral swab.
In South Korea, more than 160 recovered patients have later tested positive for a second time. Similar cases were also reported in mainland China, Macau, Hong Kong, Taiwan, Vietnam and the Philippines, with some positive cases arising as long as 70 days after the person was first discharged.
The World Health Organization warned last week that there was so far no evidence that people infected by the virus would not get infected again.
But Professor Zhong Nanshan, a renowned epidemiologist and leading scientific adviser for containing the pandemic, said there was no direct proof that a recovered patient could infect another person.
COVID-19 patients who are getting an experimental drug called Remdesivir have been recovering quickly, with most going home in days (Photo by Ulrich Perrey/Pool/AFP)
After all the time spent on effective vaccines for COVID-19, American researchers finally released some good news about a possible treatment on Wednesday. There is evidence that the experimental drug Remdesivir might help patients recover more quickly from the infection. Dr. Anthony Fauci, one of the world’s leading experts on infectious diseases, described the drug’s effect on the virus as “clear-cut and significant.”
The US Food and Drug Administration has not yet approved any drugs for the treatment of the coronavirus. But it plans to announce an emergency-use authorization for Remdesivir, according to The New York Times. This is the first time any medication has been shown to improve outcomes against COVID-19, and researchers say more work is needed.