The Lancet Infectious Diseases
What reinfections mean for COVID-19
Akiko Iwasaki
Published:October 12, 2020
One of the key questions in predicting the course of the COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is how well and how long the immune responses protect the host from reinfection. For some viruses, the first infection can provide lifelong immunity; for seasonal coronaviruses, protective immunity is short-lived.
In The Lancet Infectious Diseases, Richard L Tillett and colleagues describe the first confirmed case of SARS-CoV-2 reinfection in the USA. A 25-year-old man from the US state of Nevada, who had no known immune disorders, had PCR-confirmed SARS-CoV-2 infection in April, 2020. He recovered in quarantine, testing negative by RT-PCR at two consecutive timepoints thereafter. However, 48 days after the initial test, the patient tested positive again by RT-PCR. Viral genome sequencing showed that both specimens A and B belonged to clade 20C, a predominant clade seen in northern Nevada. However, the genome sequences of isolates from the first infection (specimen A) and reinfection (specimen B) differed significantly, making the chance of the virus being from the same infection small.
What is worrisome is that SARS-CoV-2 reinfection resulted in worse disease than did the first infection, requiring oxygen support and hospitalisation.