In Hong Kong, a patient was diagnosed a second time positive for the SARS-CoV-2 coronavirus, more than four months after his first infection.

In recent months, several hospitals around the world have reported positive cases after recoveries. The following question inevitably arose: can we catch this coronavirus twice? Many quickly dismissed the idea, favoring more the thesis of the presence of “traces of viruses not completely eliminated”. Like Florian Krammer, virologist at the Icahn School of Medicine at Mount Sinai in New York.

“I am not saying that reinfection is impossible, but in this short period of time, it is unlikely,” he explained last May, when interviewed by The New York Times. Even the mildest forms of infection should leave at least short-term immunity to the virus in the recovering patient. “

The growing concern over these possible cases of re-infection had nevertheless prompted the WHO to seriously consider the matter. At the time, the organization was reassuring today, explaining that affected patients were actually expelling “the remains of material from their lungs, as part of the recovery phase.”

A first confirmed case

And yet. Researchers in Hong Kong announced on Monday that they had diagnosed the world’s first proven case of reinfection with the new coronavirus. The researchers insist this is a new infection, not the first one four months earlier, reports The New York Times.

Although the patient – a 33-year-old man – had experienced symptoms (cough, headache and throat pain, fever) during his first infection, this time he had no symptoms. A drug test at Hong Kong airport, while returning from Spain via the United Kingdom, made it possible to make the diagnosis.

It should also be noted that, according to genetic analysis, these two successive infections were caused by two different strains of SARS-CoV-2.

“SARS-CoV-2 could persist in the population”

Experts had hoped that this new coronavirus behaves more like its cousins SARS and MERS which, after infection, seem to produce lasting immunity for a few years. Unfortunately, this report suggests that this may not be the case. “Our results suggest that SARS-CoV-2 may persist in the population, as is the case with other coronaviruses that cause common colds,” the researchers explain.

Therefore, it appears unlikely that herd immunity can eliminate SARS-CoV-2, “although it is possible that the following infections are less severe than the first, as was the case for this patient” , write the researchers in their study accepted for publication by the journal Clinical Infectious Diseases.

Even so, “since immunity may not last long after infection, vaccination should be considered even for people who have already been infected,” they add.

However, some specialists temper these results. Like Dr. Jeffrey Barrett of the Wellcome Sanger Institute. “It’s difficult to draw firm conclusions from a single case,” he explains. Considering the number of infections around the world, seeing a case of reinfection is not that surprising. “

Hugues Louissaint

Hugues Louissaint is an entrepreneur and writer, living in the US for over a decade. He has launched successful products such the Marabou Coffee brand, which has been highly successful in Florida. He has also been a writer for more than 5 years focusing on science, technology, and health. He writes part-time for the Scientific Origin and provides valuable input on a wide range of subjects.