In recent weeks, a number of countries started urging people to wear masks, as did state and local officials in America. But the Centers for Disease Control and Prevention (CDC) continued to tell people to wear masks only if they were sick or were a frontline worker like a doctor or police officer.
What changed?
Earlier recommendations were “based on the best evidence available at the time,” Adams told reporters in Washington on April 3 as officials announced the new recommendations. The evidence showed wearing a mask wouldn’t have a significant impact on whether or not a healthy person would contract COVID-19.
“We now know from recent studies that a significant portion of individuals with coronavirus lack symptoms,” Adams said. Even people who eventually develop symptoms can spread the virus before they show symptoms.
“We are constantly looking at new data and one of the new information [sic] that became clear is: there is a greater number of people that are asymptomatically infected than we previously thought,” Redfield told reporters at the White House.
Officials said the younger a person is, the more likely they are to be asymptomatic. They also urged people to follow social distancing guidelines, claiming the virus can’t jump from one person to another if it has to go more than six feet.
- A February 19 study examining asymptomatic cases in a family in China
- A February 21 letter from researchers saying they found a presumed asymptomatic carrier
- A March 5 study looking at transmission from a person showing no symptoms to a healthy Germany businessman
- A March 16 research article that estimated 86 percent of all CCP virus infections were undocumented, meaning patients showed mild, limited, or no symptoms
- A March 19 study that found a similar amount of the CCP virus in asymptomatic patients than that found in symptomatic patients
- The April 1 report from CDC researchers looking at patients in Singapore
- An April 3 report from the CDC that found approximately half of residents in a Washington nursing home who tested positive were asymptomatic or presymptomic on the day of testing.