New
studies in several countries and a large coronavirus outbreak in
Massachusetts bring into question reassuring assertions by US officials
about the way the novel virus spreads.
These
officials have emphasized that the virus is spread mainly by people who
are already showing symptoms, such as fever, cough or difficulty
breathing. If that's true, it's good news, since people who are
obviously ill can be identified and isolated, making it easier to
control an outbreak.
But
it appears that a Massachusetts coronavirus cluster with at least 82
cases was started by people who were not yet showing symptoms, and more
than half a dozen studies have shown that people without symptoms are
causing substantial amounts of infection.
For weeks, federal officials have
emphasized that asymptomatic transmission can happen, but have said that
it's not a significant factor in the spread of the virus.
On March 1 on
ABC's This Week,
US Secretary of Health and Human Services Alex Azar told host George
Stephanopoulos that asymptomatic spread is "not the major driver" of the
spread of the new coronavirus.
"You
really need to just focus on the individuals that are symptomatic," he
said. "It [the containment strategy] really does depend on symptomatic
presentation."
"Some spread might be possible before
people show symptoms; there have been reports of this occurring with
this new coronavirus, but this is not thought to be the main way the
virus spreads," according to the website.
Spokespeople for Azar and the CDC did not respond to requests for comment from CNN.
But
during a press briefing at the White House on Saturday, the
administration's coronavirus response coordinator, Dr. Deborah Birx,
seemed to strike a somewhat different note on asymptomatic transmission.
She
said they're trying to understand people under the age of 20 who don't
have "significant symptoms" -- "Are they a group that are potentially
asymptomatic and spreading the virus?" she asked.
"Until
you really understand how many people are asymptomatic and
asymptomatically passing the virus on, we think it's better for the
entire American public to know that the risk of serious illness may be
low, but they could be potentially spreading the virus to others.
"That's why we're asking every American to take personal responsibility to prevent that spread."