COVID-19 Redux: Re-infection Confirmed by Whole Genome Sequencing

Reviewed by James “Brad” Cutrell, MD, FIDSA; UT Southwestern Medical Center

Despite prior reports of COVID-19 “re-infection”, these early cases were based on persistent or repeat positive PCR without viral genome analysis to definitely establish a second infection. Kelvin Kai-Wang To and colleagues recently reported the case of an immunocompetent patient with a second asymptomatic COVID-19 infection which occurred 142 days after the first symptomatic infection. Whole genome sequencing, comparative genomic analysis and phylogenetics confirmed that the viruses from the first and second episodes came from two different SARS-CoV-2 clades, establishing a true “re-infection” rather than persistent viral shedding. Although the correlates of protective immunity and the frequency of true “re-infection” is unknown, this case raises important questions regarding herd immunity via natural infection or vaccine to stem the COVID-19 pandemic.


To KK, Hung IF, Ip JD, et al. COVID-19 re-infection by a phylogenetically distinct SARS-Coronavirus-2 strain confirmed by whole genome sequencing. Clin Infect Dis. 2020 Aug 25: ciaa1275.

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