How Soap Suds Kill the Coronavirus

A closer look at how washing your hands with soap and water for 20 seconds kills this lethal virus.

The new coronavirus has proven deadly, but it can also be defeated with something as simple as soap suds. In this animation, Health Matters explains how handwashing with soap kills the coronavirus and why it’s the best defense against the spread of COVID-19.

“Soap molecules disrupt the fatty layer or coat surrounding the virus, ” says Dr. David Goldberg, an internist and infectious disease specialist at NewYork-Presbyterian Medical Group Westchester and an assistant professor of medicine at Columbia University Vagelos College of Physicians and Surgeons. “Once the viral coat is broken down, the virus is no longer able to function.”

The best way to protect yourself from the coronavirus remains avoiding exposure — and helping to prevent its spread. That’s why the Centers for Disease Control and Prevention encourages social distancing, wearing a face mask in public places, and, of course, handwashing with soap. “Contaminated hands are one of the most important means of spread,” says Dr. Goldberg. “If you get the virus on your hands and touch your face, you can become infected. Also, if you touch someone else or some object which is then touched by someone else, the hands of that person can become contaminated, leading to further spread.”

In addition to soap and water, there’s one more thing to consider: time. That’s why the 20 seconds of handwashing with soap is so important. You work up a good lather, allowing the soap to do its magic. “The soap molecules need some time to react with the viral coat and break it up,” says Dr. Goldberg. “The process is reasonably fast, but it’s not instantaneous.”

To understand the science behind how handwashing with soap kills coronavirus, read the explanation in the animation:

You’ve probably heard that protecting yourself from COVID-19 means washing your hands for two rounds of the happy birthday song or 20 seconds of another favorite tune.

It may seem pretty mundane and simple, but a deep handwash is incredibly lethal to viruses. So why is soap such an effective killer against the novel coronavirus?

Let’s take a closer look at that dollop of soap in your hand. A soap molecule consists of a “head” that is hydrophilic — attracted to water — and a long hydrocarbon “tail” made of hydrogen and carbon atoms that is hydrophobic — or repelled by water.

When soap molecules dissolve in water, they arrange themselves into micelles, which are spherical clusters of soap molecules with the water-attracting heads on the outside and water-repelling tails on the inside.

The coronavirus has a core of genetic material surrounded by an outer sheath that’s a double layer of fats with protein spikes. This fatty sheath is water-repelling and protects the virus.

Let’s see what happens when we start washing our hands.

Back to the micelles: With a formation of water-attracting heads on the outside, and water-repelling tails on the inside that can dissolve fats, micelles become a lethal bundle of cells in water.

When they encounter coronaviruses, the water-repelling tails are attracted to the fatty envelope around the virus and insert themselves into the protective layer.

The virus shatters and is doomed down the drain.

But this doesn’t happen immediately. You need to take time to generate a good lather and cover all parts of your hands. That takes about 20 seconds.

And that’s why washing your hands is so effective in slowing the spread of the coronavirus.

Each time you create suds, you’re unleashing molecular assassins to attack and kill coronaviruses and, for that matter, nearly all other pathogens.

Read this story in Chinese or Spanish.