Researchers identify first case of COVID-19 reinfection

By Paul Basilio
Published August 24, 2020

Key Takeaways

A 33-year-old man in Hong Kong appears to be the first confirmed patient to be reinfected with SARS-CoV-2, according to researchers at the University of Hong Kong.

“An apparently young and healthy patient had a second case of COVID-19 infection [that] was diagnosed 4.5 months after the first episode,” the researchers said in a statement.

During the patient’s first infection in late March, he reported only mild symptoms. He tested positive for the second time following a trip to Spain in August, and the sequenced virus closely matches the strain circulating in Europe at this time. He is currently asymptomatic.

“Our results prove that his second infection is caused by a new virus that he acquired recently rather than prolonged viral shedding,” said Kelvin Kai-Wang To, MD, a clinical microbiologist at the University of Hong Kong.

While scattered reports of reinfection have been documented, those reports have typically relied on anecdotal evidence and have been attributed to problems with testing. 

The current findings raise alarms over the durability of immunity following infection with SARS-CoV-2, but some experts are hesitant to comment on the extent to which the case can be applied to the global pandemic at large.

“There’s been more than 24 million cases reported to date,” said Maria Van Kerkhove, PhD, COVID-19 Technical Lead at the World Health Organization. “And we need to look at something like this at a population level.”

The robustness of the immune response triggered by SARS-CoV-2 infection has been a hot topic since the beginning of the outbreak. While protection against SARS-1 and MERS can last several years, infection with common cold coronaviruses trigger an immune response that can wane in less than 1 year.

The type of immune response mounted by the body in response to infection with SARS-CoV-2 is also largely unknown. Some patients fail to produce a high enough level of neutralizing antibodies that block the virus from infecting cells.

“The fact that somebody may get reinfected is not surprising,” Malik Peiris, MBBS, a virologist at the University of Hong Kong who is not affiliated with the current report, but who is familiar with the case, told STAT News. “But the reinfection didn’t cause disease, so that’s the first point. And the second thing is that it is important to know whether the patient mounted a neutralizing antibody response to the first infection or not. Because the vast majority of patients in our experience do mount a good neutralizing antibody response. So is this person an outlier or is he likely to be the average person infected?”

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