The coronavirus that causes COVID-19 may
spread through the air in tiny particles that infected people exhale during
normal breathing and speech.

Until now, experts
have said
that the virus, called SARS-CoV-2, doesn’t spread through the air
in that way, but rather through relatively large droplets released when people
cough or sneeze. Those droplets can contaminate surfaces or objects and infect people
who touch the surface and then touch their faces.

Large droplets are still a means of
infection, but researchers now say that tiny airborne particles may also carry
infectious virus. “Currently available research supports the possibility that SARS-CoV-2
could be spread via bioaerosols
generated directly by patients’
exhalation,” researchers from the U.S. National Academies of Science,
Engineering and Medicine wrote in an April 1 report to the White House Office
of Science and Technology Policy.

If the coronavirus is airborne, that could help explain why it is so contagious, and can spread before people have symptoms (SN: 3/13/20).

As of April 2, more than 1 million
people worldwide are confirmed to have COVID-19, with nearly a quarter of those
cases in the United States, according to tracking by Johns Hopkins University.
More than 50,000 people have died worldwide, including more than 5,600 people
in the United States.

Wearing surgical masks can cut down on the
amount of virus that infected people spread, the expert panel says, citing an
unpublished study from the University of Hong Kong. The letter does not address
whether wearing
a mask
will protect the person wearing the mask from catching the illness (SN: 3/27/20). How much virus a person
must breathe in to get infected isn’t known.

The report also notes that genetic material from the virus was detected more than two meters (six feet) away from patients’ hospital beds. That finding could indicate that physical distancing by at least two meters may not be enough to limit spread of the virus. Whether infectious virus could be carried that far or if the genetic material is from dead viruses isn’t yet known.