Viral kinetics in SARS-CoV-2 infected asymptomatic patients

Introduction: As the daily number of patients diagnosed with SARS-CoV-2 infection by PCR increases, necessity to identify truly infectious cases becomes more significant. We aimed a cut-off Ct value COVID-19 RT-PCR assay for likely infectivity assessing IgG status and investigating utility Rapid Antigen Test (RAT) in identifying among asymptomatic individuals. Methods: Nasopharyngeal/throat swabs were simultaneously taken RAT from 552 individuals at De Soysa Maternity Hospital, Colombo, 23rd November 19th December 2020. In addition, (against nucleoprotein) positive was evaluated when sera available. Results: rate 14.3% (n=79). The overall sensitivity 30.4% but increased 73.9% values below 25 considered. response 37 subjects seropositivity 40.5%. optimal thresholds discrimination 30.5 30.29 E S gene respectively. There significant correlation between ratio (r=0.345, p<0.05). positivity 26.5 26.06 genes respectively, negative (p<0.001). Conclusion: conclude that it is possible define cut off (with some error margin practical purposes) non-infectivity. It also deduced rapid antigen result seems be predictive comparison result.