SARS-CoV-2 Shedding Shows Huge Interindividual Variation

Significant disparities in the infective potential of SCOVID-19 patients have been observed in a study conducted at a university center. Providing possible insight into super-spreading events — a large population infected by a few individuals— the study provides a possible explanation of why such events play a disproportionately big role in the spread of the disease. In their study, from late 2020 to early 2021, during the advent of Alpha and other SARS-CoV-2 variants, 60 unvaccinated individuals with SARS-CoV-2 were identified by Christopher Brooke at the University of Illinois at Urbana– Champaign and his colleagues. For a fortnight, they collected daily samples from mild to asymptomatic patients. They found significant disparities in the number of days for which the patients shed viruses bearing infective potential: one discharged viable virus from the nose for nine days, while nine other patients did not shed any recognizable viruses capable of causing infection during the testing period. Estimates made via statistical modeling showed that the least infectious individuals shed viruses a staggering 57 times less than the most infectious individuals. Their findings reveal that viral RNA load maxed a few days after in the nose than in the saliva, and became untraceable approximately 14-21 days later. Nature Microbiol. 7, 640–652 (2022)