I never worried about getting Covid by touching something and never wiped anything down to prevent catching it. My reason for not worrying about it is partly because I’m not much of a worrier, and partly because the incidence of the disease in my area is fairly low. Plus, there are no documented cases of the virus spreading by way of contaminated surfaces. Now, scientists have figured out why that’s the case.
Covid is spread by aerosols—the fine mist we exhale as we
breathe, talk, laugh, cough, and sneeze. Early in the pandemic, some studies seemed
to show that the virus was viable on surfaces for days and even weeks. It turns
out those studies were wrong, and here’s why: the researchers used water to
simulate sneeze droplets, which does not mimic real world conditions. As
Jessica Kramer, a biomedical engineer at the University of Utah says, “…people don’t sneeze out
water. They sneeze out mucus.” Big difference, it turns out. In fact, the spit
that helps spread the virus in the air actually blocks it from later infecting
someone via surfaces.
It turns out that mucus has protective effects because of
two characteristics: it evaporates slower than water and it contains sugar and
proteins. These characteristics make a huge difference when it comes to preventing
virus transmission via a surface. What happens is, when an infected person
coughs and the virus lands on a tabletop, the virus grabs all the proteins it
can from the mucus as the surrounding fluid begins to evaporate. By the time
the virus is dry, it’s spikes—which cause infections—are full. The process, called "binding," renders the virus impotent.
So, you can stop worrying about touching surfaces and wiping
them down. It’s all been wasted effort.
For an introduction to this blog, see I Just Say No; for a list of blog topics, click the Topics tab.
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