Characterization of SARS-CoV-2 Omicron variant shedding and predictors of viral culture positivity on vaccinated healthcare workers with mild COVID-19.

In this prospective cohort of 30 vaccinated healthcare-workers with mild Omicron variant infection, we evaluated viral culture, rapid antigen test(RAT), and RT-PCR of respiratory samples at days 5,7,10, and 14. Viral culture was positive in 46%(11/24) and 20%(6/30) of samples at days 5 and 7, respectively. RAT and RT-PCR(Ct≤35) showed 100% negative predictive value(NPV), with 32% and 17% of positive predictive values(PPV), respectively, for predicting viral culture positivity. A lower RT-PCR threshold(Ct≤24) improved culture prediction(PPV = 39%; NPV = 100%). Vaccinated persons with mild Omicron infection are potentially transmissible up to day 7. RAT and RT-PCR might be useful tools for shortening the isolation period. [ABSTRACT FROM AUTHOR]