People without CCP virus symptoms should get tested if they think they were exposed to the virus, said Dr. Robert Redfield, director of the Centers for Disease Control and Prevention (CDC).
Cases of infection were overall on the rise in 34 states over the past week, with 12 recording an increase of more than 50 percent, according to data from Johns Hopkins University. Three states—Kentucky, New Hampshire, and Vermont—are reporting a decline in cases.
Redfield said it's difficult to use traditional methods of tracking outbreaks because of the number of asymptomatic cases of infection. He said a large number of infected people, particularly those younger than 45, don't show symptoms, according to studies.
"Another study of skilled nursing facility residents who were infected with SARS-CoV-2 after contact with a healthcare worker with COVID-19 demonstrated that half of the residents were asymptomatic or pre-symptomatic at the time of contact tracing, evaluation, and testing," said the CDC.
The federal agency also noted that virologic studies have reported that a large quantity of viral RNA and viable viruses have been cultured from asymptomatic carriers.
"We're challenged with this virus," Redfield told ABC News.
"Expanded testing might include testing of individuals on the same unit or shift as someone with SARS-CoV-2 infection, or even testing all individuals within a shared setting (e.g., facility-wide testing)," said the CDC.