Doctor Wheat: the chance of detecting COVID-19 in the nasopharynx decreases on the 4-5th day of illness 
The work of the Central Research Institute of Epidemiology of Rospotrebnadzor, Professor Natalya Pshenichnaya explained why the test for the presence of an infection often gives a negative result with a coronavirus. According to her, this is due to the course of the disease, RIA Novosti reports.
The doctor explained that the chance of detecting COVID-19 depends on the duration of the illness.
“After 4-5 days illness, the likelihood of detecting a virus in the nasopharynx decreases, and respiratory symptoms may be in full swing at this time. If you test within these terms, you can get a negative result, “Pshenichnaya emphasized.
Earlier, geneticist Andrei Isaev advised to selectively test company employees for coronavirus by PCR. In his opinion, rapid studies for the presence of infection cannot become a full-fledged alternative to PCR testing.
The specialist believes that in order to effectively combat the incidence of coronavirus, it is necessary to selectively screen workers in collectives for infection. “This method was effective, but in the summer it was abandoned,” lamented Isaev.