Nearly 25 percent of people infected with the new coronavirus may not show symptoms, says Centers for Disease Control and Prevention of the US.
“This helps explain how rapidly this virus continues to spread across the country,” said Dr Robert Redfield, Director, CDC in an interview.
In light of the new data indicating a high level of symptom-free cases, the CDC is considering broadening its guidelines on who should wear masks, reports said.
The CDC and the WHO has recommended that only people who are unwell with infection wear masks. Earlier an analysis found about 18 percent of people infected with the virus on the Diamond Princess cruise ship never developed symptoms.
Meanwhile, China’s Global Times newspaper reported the transmission risk of asymptomatic patients was similar to those with symptoms. It said 6.3% of a confirmed case’s close contacts were infected with the virus, compared to 4.4% for an asymptomatic carrier, according to the Ningbo Center for Disease Control and Prevention in Zhejiang Province.
Experts said that between 20% and 40% of transmission events occurred in China before symptoms appeared.