How, exactly, does Covid-19 spread?

How, Exactly, Does Covid-19 spread?

The virus
that causes Covid-19 has infected more than 276,000 people since its emergence.
(Of them, at least 11,417 have died.) That’s just the confirmed cases.

Why has it
spread so fast? “The best explanation for this rapid spread is that the virus
is being passed through droplets from coughing or sneezing,” Vox’s Julia Belluz
explains. “When these virus-laden droplets from an infected person reach the
nose, eyes, or mouth of another, they can transmit the disease.”

But it’s
still unknown how significant other modes of transmission are in spreading the
disease.

It’s
possible that the virus can spread through feces. (The CDC says, though, “the
risk is expected to be low based on data from previous outbreaks of related
coronaviruses.” But if you weren’t already washing your hands vigorously after
defecating, please do so now.)

You may have
heard that the new coronavirus isn’t “airborne” — meaning that unlike extremely
contagious diseases like measles, it’s unlikely to linger in the air for hours
on end. But that doesn’t mean the virus can’t linger in the air for some amount
of time.

As Wired
explains, although some experts say the new coronavirus isn’t airborne, that’s
based on a narrow scientific definition of the term. The virus can possibly
still linger in the air for some time and under some conditions. As the journal
Stat reports, we don’t yet know precisely what those conditions are. It will
definitely be in the air in the moments after an infected person sneezes or
coughs, but it’s unclear when the particles eventually come to rest on the
ground or surrounding surfaces.

“The studies
suggesting that this virus can be aerosolized. i.e linger as small particles in
the air are only preliminary, and other research contradicts it, finding no
aerosolized coronavirus particles in the hospital rooms of Covid-19 patients,”
Stat reports. More research is needed.

So all three
transmission routes — droplets, airborne, and fecal — are still possible
contributors to the spread of the virus. “Almost certainly, one of these is
probably the predominant one, and the others might be minor modes of
transmission, but we don’t really understand this,” Hotez says. Some good news
is that scientists are figuring out how long the virus can live on some
surfaces. Here’s the latest:

It’s around
three days for plastic and steel,

about a day
for cardboard,

and less
than a day for copper.

This
information helps direct sanitation efforts to where they are needed most.