Hong Kong Researchers Report the First Confirmed COVID-19 Reinfection Case

Researchers in Hong Kong have confirmed the first patient to be reinfected with COVID-19, suggesting that those who recover may only have short-lived immunity to the virus.

A 33-year-old man in Hong Kong has just become the first confirmed patient reinfected with the coronavirus, according to researchers at the University of Hong Kong. The findings suggest that those who have been infected with the virus may be immune from reinfection but only for a short period of time.

Experts say that this result is not surprising given the millions of people worldwide who have become infected with the coronavirus. Researchers said that the reinfected man did not show any symptoms of having become infected the second time, suggesting that even though the prior exposure did not prevent the reinfection, his immune system kept him from becoming severely impacted. 

"The second infection was completely asymptomatic — his immune system prevented the disease from getting worse," said Akiko Iwasaki, an immunologist at Yale University who was not involved with the work but reviewed the report at the New York Times' request. "It's kind of a textbook example of how immunity should work."

The man had originally been infected with the virus back in March with mild symptoms. He was hospitalized on March 29, but his symptoms subsided and he was discharged on April 14, according to the study. The second infection occurred more than four months later, reportedly after the man returned to Hong Kong from Spain — where cases continue to rise after a recent surge. The patient tested positive on Aug. 15 and was hospitalized but remains asymptomatic. 

The findings that previously infected patients can become reinfected as an asymptomatic case underlines the importance of social distancing, face coverings and other restrictions to keep the risk of spread at a minimum. Doctors have said that when a vaccine becomes available, even those that have been infected in the past, should be vaccinated. While an initial infection may keep you from getting sick again, it does not keep you from contracting the virus once more and spreading it to others.

Doctors have reported several cases of presumed reinfection in the United States and elsewhere, but this Hong Kong case is the first to be confirmed with testing. 


About the Author

Sydny Shepard is the former editor of Occupational Health & Safety.

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