This article discusses subjects that are scientific in nature. Therefore, a list of references is included at the end. When I say something that needs supporting through a reference, the name of the source and the year of the information is in braces ( and ).
Most of us were told to wash our hands, as children, before we started to eat dinner, after we came in from playing outside, and after going to the bathroom. Similarly, many of us will have seen signs in restaurant bathrooms, or the bathrooms of stores like Target or Tesco, which say “Employees must wash hands before returning to work”.
So that suggests we should wash our hands at those times, and not otherwise. But this is a problem for our health. Viruses, such as the currently-newsworthy COVID-19 are spread by droplets landing on surfaces [usually hard surfaces] where they can remain until touched by someone else, and then transferred to the nose, eyes, or mouth (CDC, 2019). If you are on a train, a bus or anywhere else where there are other people, there is a chance that a virus is sitting on that hand rail, turnstile bar, door handle, or cash register card reader (Telegraph, 2020).
When you should wash your hands
The CDC says that you should wash your hands after touching garbage [rubbish in UK English], using the bathroom, before eating and in other situations in which it should be obvious (CDC, n.d.).
In order not to pick up viruses from other people, we really should wash our hands whenever we touch a surface that someone else might have touched. Alternatively, we can avoid touching our faces after we have touched such a surface, and before we have washed our hands, but research suggests we touch our faces up to 23 times a day (Telegraph, 2020). I for one, definitely touch my face more often than that.
How you should wash your hands
The CDC says that you should make your hands wet using warm or cold water [hot water does not confer any benefit], turn off the faucet [tap in UK English] and scrub your hands for 20 seconds while you do so (CDC, n.d.). 20 seconds is how long it takes to hum “Happy Birthday” twice which, I hope, you can do silently. Just do it silently – no-one wants to hear Happy Birthday being hummed every time they go to a public bathroom.
Hand sanitizer is a useful additional measure, but it should never be used in place of soap and water, if it’s available (CDC, 2019).
Studies in hospitals show that too-frequent use of hand sanitizer can cause resistance to evolve in viruses and bacteria, but that is not a reason not to use it whenever appropriate (CDC, 2019; CNN, 2018).
CDC. 2020: https://www.cdc.gov/coronavirus/2019-ncov/about/transmission.html
CDC. n.d.: https://www.cdc.gov/handwashing/show-me-the-science-handwashing.html
CDC. (2019): https://www.cdc.gov/handwashing/show-me-the-science-hand-sanitizer.html
CNN. (2018): https://www.cnn.com/2018/08/02/health/hand-sanitizer-bacteria-resistance-study/index.html
Telegraph. 2020: https://www.telegraph.co.uk/science/2020/03/06/deadly-doorknob-science-coronavirus-contamination/