Home News The science of soap – here’s how it kills the coronavirus

The science of soap – here’s how it kills the coronavirus



can be active outside the body for hours, even days. Disinfectants,
liquids, wipes, gels and creams containing alcohol are all useful at
getting rid of them – but they are not quite as good as normal
soap. When I shared the information above using Twitter, it went
viral. I think I have worked out why. Health authorities have been
giving us two messages: once you have the virus there are no drugs
that can kill it or help you get rid of it. But also, wash your hands
to stop the virus spreading. This seems odd. You can’t, even for a
million dollars, get a drug for the coronavirus – but your
grandmother’s bar of soap kills the virus. So why does soap work so
well on the Sars-CoV-2, the coronavirus and indeed most viruses? The
short story: because the virus is a self-assembled nanoparticle in
which the weakest link is the lipid (fatty) bilayer. Soap dissolves
the fat membrane and the virus falls apart like a house of cards and
dies – or rather, we should say it becomes inactive as viruses
aren’t really alive. The slightly longer story is that most viruses
consist of three key building blocks: ribonucleic acid (RNA),
proteins and lipids. A virus-infected cell makes lots of these
building blocks, which then spontaneously self-assemble to form the
virus. Critically, there are no strong covalent bonds holding these
units together, which means you do not necessarily need harsh
chemicals to split those units apart. When an infected cell dies, all
these new viruses escape and go on to infect other cells. Some end up
also in the airways of lungs.