Researchers confirm first case of COVID-19 reinfection in Hong Kong

Kwok-Yung Yuen, the University of Hong Kong, and colleagues' manuscript has been accepted for publication in the above-mentioned journal but is yet to be published. 

Although there has been previous news of COVID-19 reinfection but such cases were never documented. As what appeared to be reappeared was simply prolonged infection according to many experts. But in this case, the researchers confirmed it to be a case of reinfection and not persistent viral shedding from the first infection, through epidemiological, clinical, serological and genomic analyses.

Whole genome sequencing found the first viral genome to be 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.

Other evidence that researchers offered that it was indeed reinfection was relatively high viral load with gradual decline and elevated C-reactive protein in the patient. Also, there was long period of 142 days between infections considering that viral RNA is undetectable one month after symptom onset, and prolonged viral shedding has only ever been documented up to 104 days after infection.

"Our findings suggest that SARS-CoV-2 may persist in the global human population as is the case for other common-cold associated human coronaviruses, even if patients have acquired immunity via natural infection," the authors wrote in a press release.