Two staff members at a tertiary hospital in north India tested positive for the new coronavirus and became reinfected several months later — both times without showing any symptoms of COVID-191.
During routine surveillance, researchers at the CSIR Institute of Genomics and Integrative Biology (IGIB) in Delhi and Academy of Scientific and Innovative Research (AcSIR) in Ghaziabad, Uttar Pradesh detected the reinfection in the healthcare workers — a 25-year-old-man and a 28-year-old woman, working in the COVID-19 ward.
Both the hospital employees tested positive for SARS-CoV-2 in May without displaying any symptom. They later tested negative and returned to work. Roughly three-and-a-half months after the first positive test, they both tested positive again. This time too they didn't have symptoms, but both had higher levels of virus than in May.
Genomic analysis by Vinod Scaria at IGIB and his colleagues showed that the second infection was by a genetically different SARS-CoV-2 than the first — confirming that it was a reinfection and not leftover virus.
The results suggest that asymptomatic reinfections are often underreported, the authors say.
1. Gupta, V. et al. Asymptomatic reinfection in two healthcare workers from India with genetically distinct SARS-CoV-2. Clin. Inf. Dis. (2020) doi: 10.1093/cid/ciaa1451