A large percentage of COVID-19 patients may never show symptoms of the virus at all, which is a major factor helping to spread the virus, according to a senior US medical official.
The director of the Centers for Disease Control and Prevention, Dr. Robert Redfield, said that up to 25% of people with the new coronavirus are asymptomatic.
“This is important, because you now have individuals who may not have any symptoms that contribute to the transmission of the disease,” Redfield said.
Even more, even if people get sick, they may conceal the virus for up to 48 hours before they develop symptoms, he added. “This helps explain how quickly this virus spreads across the country, because we have vectors without symptoms and we have individuals transmitting the virus 48 hours before symptoms appear,” Redfield said.
Recent studies from other countries also show that a non-symptomatic transmission of COVID-19 is possible. For example, a study published on April 1 in a journal issued by the CDC found that among more than 150 non-travel-related COVID-19 cases in Singapore, 6.4% appeared to involve asymptomatic transmission. In another study, published on March 19, scientists reviewed data on COVID-19 in China outside Hubei Province, and found that 12.6% of cases appeared to involve asymptomatic transmission.
In the light of these data on asymptomatic spread, Redfield said, the Centers for Disease Control and Prevention “strongly” reviews its recommendations on the use of face masks and whether people should wear them if they have no symptoms.
Currently, the agency recommends face masks only for healthcare providers and people with COVID-19.
However, there is concern that changing these recommendations by expanding use could reduce the availability of medical face masks to health-care workers who need them most.
Source: Life Science