A review of 79 studies on viral loads in people — specifically, SARS-CoV-2, SARS-CoV-1 and MERS-CoV — has shown that (1) ‘viral RNA can persist in and be shed from the body for long periods of time (more than 80 days in some cases)’ although ‘SARS-CoV-2 only remains viable and infectious for approximately one week after the onset of symptoms’ (2) ‘Viral load was at its highest approximately 3-5 days after the onset of symptoms, and there was a positive correlation between prolonged viral shedding and disease severity. Older patients also experienced prolonged viral shedding compared to younger patients, even when accounting for disease severity...
‘While there are fewer studies on the kinetics of viral load for asymptomatic infections, viral shedding appeared to be of a shorter duration, and overall viral load appeared to be lower compared to symptomatic cases.’
The authors conclude that (1) ‘PCR testing is likely not a good tool for evaluating patient recovery, because viral RNA is detectable long after the end of the infectious period’. (2) ‘Early case detection and isolation should be prioritised in order to maximise control efforts during the time when patients are the most infectious.’ -- Center for Health Security, John Hopkins University
https://www.medrxiv.org/content/10.1101/2020.07.25.20162107v2.full.pdf
Read here (Medrxiv, July 25, 2020)
