In a paper accepted on [August 24] by the Clinical Infectious Diseases journal, scientists from the University of Hong Kong reported the case of a 33-year-old man who had an asymptomatic Covid-19 episode 4½ months after a symptomatic infection.
The findings, based on a single patient, would if replicated bolster the theory that immunity to SARS-CoV-2, the virus that causes Covid-19, could last only a few months, similar to coronaviruses that cause the common cold.
That would have implications for recommended precautions for recovered patients and for cycles of vaccinations once they become available. The case report also highlights the importance of widespread rapid testing and isolation of cases, experts said.
The paper didn’t specify whether the patient was infectious the second time around, but infectious-disease researchers and virologists have said for months that social distancing, good personal hygiene and masking would continue to be important for stemming the spread of the virus until more is known about how long immunity lasts, whether from natural infection or vaccination.
“This paper doesn’t answer the question of how long would [immunity] last if you had a more robust antibody response,” [infectious disease specialist at the University of California San Francisco Peter Chin-Hong] said. Still, “this is probably not the first case they’re going to find. This is only the beginning.”
