One very small study involving four patients from China suggests that some recovered patients may still be virus carriers.
“They’ve been screening patients after they recover to see how long they’re shedding some of the genetic material that’s very specific to the new coronavirus,” said Dr. Thomas Russo, an infectious disease expert with the University at Buffalo Jacobs School of Medicine and Biomedical Sciences.
Russo tells News 4 that researchers are discovering that even after people have recovered, there’s still a footprint, and that the virus’ genetic material is present for days, and in some instances as much as weeks afterwards.
“So, what the practical implications are, and we still don’t know a 100 percent for sure if this is live viable virus. But I think it likely will be the case,” Russo said. “And this means that when someone recovers, they potentially, and I think the key word here is potentially, could be infectious and transmit the virus to other individuals.”
For example, a research letter published in the Journal of the American Medical Association last month involving COVID-19 patients in China, suggests a “proportion of recovered patients still may be virus carriers.”
“The study was limited to a small number of patients with mild or moderate infections,” the paper stated.
“People are generally looking at three, four, five patients on that order of magnitude,” Russo explained.
He says more careful testing and research needs to be done to determine the true implications. In other words, how long could this particular virus be shed in an infectious form.
“And that information will be critical for us then being able to give the proper advice to minimize transmission and subsequent infections,” Russo said.
According to the research letter, “After hospital discharge or discontinuation of quarantine, the patients were asked to continue the quarantine protocol at home for 5 days. The RT-PCR tests were repeated 5 to 13 days later and all were positive. All patients had 3 repeat RT-PCR tests performed over the next 4 to 5 days and all were positive. An additional RT-PCR test was performed using a kit from a different manufacturer and the results were also positive for all patients. The patients continued to be asymptomatic by clinician examination and chest CT findings showed no change from previous images. They did not report contact with any person with respiratory symptoms. No family member was infected.”
There’s been talk and speculation about the possibility of reinfection. Russo says this is a question that really remains unclear.
“Our hope is that once you’re infected with this virus, you’ll develop protective immunity. And that immunity in a perfect world will last a lifetime. But this is something that we’re going to have to study and see,” Russo said.
He says even if infected patients don’t get durable or lifetime immunity, the hope is that the development of a vaccine could be used to boost immunity to protect people in the future.