Religious handwashing rituals have been around for thousands of years in Islamic, Jewish and other cultures, but the notion of disease spreading by hand has been part of the medical belief system for only about 130 years. вЂњBeing a historian of this kind of pandemic event and then experiencing this one,вЂќ she says, вЂњis kind of like being a passenger on the Titanic and watching it all unfold.вЂќ It also feels, she says, like going back to the early 20th century, when infectious diseases such as tuberculosis and smallpox were the No 1 cause of death, and the new science of germs had led to the first mass obsession with hand hygiene.

To Nancy Tomes, a distinguished professor of history at Stony Brook University, New York, seeing this basic advice headlining the public health agenda has felt even more strange. A website for generating handwashing infographics to the song lyrics of your choice has gone viral.

Judi Dench and Gyles Brandreth have posted themselves online reciting The Owl and the Pussycat with sudsy hands. The KillersвЂ™ frontman, Brandon Flowers, tweeted a video of himself lathering up while crooning his hit Mr Brightside to 4 million followers. And all our leader had was this?ДЄs one of the few things we can do to significantly stop the spread of coronavirus while out in the infectious world, the new rules for this everyday habit have become the meme du jour. The preppers among us had panic-shopped while awaiting his pronouncements, and others fretted about vulnerable loved ones, travel plans, the nightmare of simultaneous homeworking and home-schooling, and not being able to work at all. I t felt strange when Boris Johnson emerged from the first Covid-19 Cobra meeting on 2 March and told us to wash our hands while singing Happy Birthday.

Keep it clean