Hong Kong researchers announced that a man was reinfected with the novel coronavirus, suggesting that immunity doesn’t last very long.
The man was diagnosed with COVID-19 on March 26, hospitalized, then recovered. He tested positive for SARS-CoV-2 again on August 15, and whole genome sequencing of viral isolates from the two episodes indicated they were from different clades, reported Kwok-Yung Yuen, MD, of the University of Hong Kong, and colleagues in a manuscript they said had been accepted for publication in Clinical Infectious Diseases, but not yet published.
“We report the first case of reinfection of COVID-19,” they wrote. “Epidemiological, clinical, serological and genomic analyses confirmed that the patient had reinfection instead of persistent viral shedding from first infection.”
Indeed, whole genome sequencing found the first viral genome was most closely related to SARS-CoV-2 strains from the U.S. or England collected in March/April strain and the second viral genome was most closely related to strains from Switzerland and England in July/August. There were 24 nucleotide differences suggesting different strains.