BRUXELLES, BELGIUM - APRIL 20 : Illustration picture shows nursing staff handling corona test tube for polymerase chain reaction (PCR) pathogens.
Covid-19 test are used to screen infected people for the coronavirus. PCR tests work by detecting specif WASHINGTON (FOX 5 DC) - Asymptomatic COVID-19 patients are of great concern to public health officials and lawmakers due to their ability to spread the virus without knowing they're sick themselves.
Now, the Centers for Disease Control and Prevention estimates that more than a third of COVID-19 patients could be asymptomatic. RELATED: CDC: We could be wearing masks for another year The new guidance, which the agency says is "designed to help inform decisions by modelers and public health