Coronavirus reinfection is possible but here’s what you should know

When The World Health Organization officially classified the novel coronavirus crisis a pandemic back in March, officials launched an international clinical trial to collect all relevant data.

It soon after became apparent that host–SARS-CoV-2 interactions vary wildly depending on a growing list of factors. Somewhere among these factors are the means that define an optimal auto-immune response.

Those who recover from COVID-19 develop antibodies that bind to the novel coronavirus responsible for the respiratory disease before it can penetrate healthy cells.

Initial reports suggested that protective immunity may be lost by six months post-infection.  This conclusion was supported by an analysis conducted on rhesus monkeys.

Others have posited transient immunity: our immune response is geared against SARS-CoV-2 reinfection during and immediately after viral clearance but not for much longer than that.

There wasn’t much of a consensus on outcomes linked to re-exposure among human populations.

New data published in the journal, Clinical Infectious Diseases, confirms that SARS-CoV-2 reinfection is possible based on the first recorded case that emerged this month in Hong Kong.

“This is the world’s first documentation of a patient who recovered from Covid-19 but got another episode of Covid-19 afterwards,” the authors said in a media release.

The 33-year-old man developed symptoms in March (cough, sore throat, fever, and headache), tested positive for the novel coronavirus, recovered, and then tested positive again just last week–although this time he remained asymptomatic.

As previously covered by Ladders, a positive COVID-19 antibody test indicates that your immune system has encountered SARS-CoV-2 but it says very little else beyond that.

In addition to the 10% chance for false positives and negatives associated with most novel coronavirus testing kits, it’s also believed that genetic remnants linger after recovery. This new report documents the first instance of someone completely dispelling of SARS-CoV-2 and contracting it again. The authors know this because the patient tested positive for two separate strains.

On balance, reactions to the new paper among the academic community range from optimism and mild alarm.

“There’s been more than 24 million cases reported to date,” Maria Van Kerkhove, a coronavirus expert at the World Health Organization, said at a briefing Monday, when in reference to the new Hong Kong report. “And we need to look at something like this at a population level. What we are learning about infection is that people do develop an immune response, and what is not completely clear yet is how strong that immune response is and for how long that immune response lasts.”

“There’s no need to panic over this reinfection news. Even though he got reinfected…this is a good example of how immunity should work in a person,” Akiko Iwasaki, a professor of immunobiology at the Yale School of Medicine said of the analysis.

The closer researchers get to uncovering all of the instructive elements related to COVID-19 immunity, the sooner establishments can assess risk for patrons, students, and workers looking to get moving again.

“What you would like is to have some blood measure that serves as a correlate of that protective efficacy or immunity,” said Sarah Fortune, the chair of immunology and infectious diseases at Harvard’s T.H. Chan School of Public Health. “Which sounds like it’s simple, but it’s much more complicated than you’d think.”