Science, Art, Litt, Science based Art & Science Communication
All these days we have been told that washing with soap and water will remove the corona virus that causes COVID 19. I have seen hundreds of advises - given by doctors, scientists, even WHO that this is the best option to avoid COVID 19 .
According to the article posted here:
Viruses such as coronavirus, influenza-causing viruses, Ebola, Zika have their genetic material encased in a layer of fat called the lipid envelop. Soap molecules are pin-shaped with a head that is water-loving (hydrophilic) and a tail that is oil-loving (oleophilic). Being oleophilic, the tail portion of the molecule tends to have an affinity for and ‘competes’ with the lipids in the virus envelope. Since the chemical bonds holding the virus together are not very strong, the long oleophilic tail gets inserted into the envelope and tends to have a ‘crowbar’ effect that breaks the lipid envelope of the virus. The tail also competes with the bond that binds the RNA and the lipid envelop thus dissolving the virus into its components which are then removed by water.
Regularly and thoroughly clean your hands with an alcohol-based hand rub or wash them with soap and water. Why? Washing your hands with soap and water or using alcohol-based hand rub kills viruses that may be on your hands.
Now contradicting these things a virologist says this: https://www.quora.com/Why-is-washing-hands-more-effective-than-hand...
I realize this answer may upset a lot of people, since it’s not what they read from 1,000s of websites and articles (some written by chemistry professors & medical professionals).
There are ZERO studies on COVID showing soap & water is better than alcohol-based sanitizer.
There is a study (3/15/20) which shows that 5 min of soaking in hand soap is not long enough to inactivate SARS-CoV-2 virus (15 min is long enough). Soaking is not the same as handwashing, but it’s the only hand soap and COVID study we have.
Washing with soap for 20 sec mainly washes most of the virus off your hands into the sink.
Washing with plain water helps
Washing with soap helps
Washing with alcohol-based hand sanitizer helps
But which works better? By how much?
Does it help to wash with soap for 60 sec? Or hand sanitizer for 20 sec?
How about soap for 20 sec compared to hand sanitizer for 60 sec?
60% alcohol vs. 70% alcohol vs. 50% soap vs. 75% soap?
Light rubbing versus heavy scrubbing?
Ethanol vs isopropyl?
Real data = Real advice
No real data = Guessing
Theoretically chemists know soap should attach to the SARS-CoV-2 outer shell and help inactivate the virus. But how long does it take in real life? If it takes longer than 5 min, then a 20 sec hand-washing may not do much “inactivation”.
(1) Washing hands with soap & water against COVID has not actually been tested and measured.
It may flush virus down the sink or onto sink/faucet/handle surfaces (where other people may be exposed, or you may catch it in the next 3–4 days), or the soap may attach to viruses and help deactivate the shell.
In tests with a non-COVID virus (rotavirus, without a shell), soap and water removed about 87+/-2%. Plain water removed about 84+/-3%. Difference is not statistically significant (“Liquid soap” and “Tap water” both in Tukey group D”)
Good news: For rotavirus, washing with tap water is almost as good as with soap. For COVID, it’s unknown. Hasn’t been studied yet.
Rotavirus (1989) - NOT COVID-19:
5 min of soaking in hand soap is not long enough to inactivate SARS-CoV-2 virus.
15 min of soaking in hand soap is enough.
5 min of soaking in 70% ethanol does inactive SARS-CoV-2.
Surprise! “Vigorous rubbing” while handwashing with soap & water may be more important than the soap. Maybe plain water will be almost as effective.
- Stability of SARS-CoV-2 in different environmental conditions (bioRxiv, 3/15/20)
(2) An alcohol-based sanitizer can inactivate 99%+ of non-COVID virus (I don’t know numbers for COVID). But you also have to scrub pretty well with the hand sanitizer.
5 min of soaking in 70% ethanol does inactivate SARS-CoV-2.
It’s unclear how quickly 70% ethanol works.
Is 2 sec long enough? 10 sec? 20 sec? 30 sec? 60 sec?
Instructions for wearing PPE (Personal Protective Equipment) for COVID-19:
(1.) “Clean gloves with alcohol-based hand sanitizer”
(3., 5., and 2nd 1.) “Clean hands with alcohol-based hand sanitizer”
Doesn’t say soap & water.
Personally, I sometimes just use plain water (84% is often good enough for me). I often don’t bother with soap, sanitizer, or disinfectant wipes when I haven’t been exposed to a lot of virus (Trying to be more environmental).
When visiting a grocery store with lots of people, I do use disinfectant wipes, hand sanitizer, and wash my hands.
A family member (doctor) told me about a contact tracing case where COVID was spread by the self-checkout machine at a grocery store. Yes, you can get sick from a surface at the grocery store. I use hand sanitizer or a disinfectant wipe on the self-checkout machine.
When I get home from the grocery store, I wash my hands, remove my N95 mask, wash my hands again, take my clothes off, take a shower, and put on house clothes (which never go outside). Then I wash any food which is going in the refrigerator or freezer (with plain water, no soap) - virus stays active longer at colder temperatures. Non-refrigerated food, I just leave untouched for a few days (for virus to inactivate).
(a) If you are taking care of a sick COVID patient, that’s a lot of virus exposure.
(b) If you take a walk outside, always 30 feet from anyone else, that’s not a lot of exposure.
NOTE: Something to watch out for in hand-washing studies:
They may be measuring 40 or 60 seconds of hand-washing (not 5 sec or 20 sec). Read the fine print.
P.S. Most people seem to catch COVID from the air (breathing within 20–30 feet of a sick person), but contact tracing has revealed cases where people caught it from a surface.
A family member (doctor) told me about a contact tracing case where COVID was spread by the self-checkout machine at a grocery store.
I personally have not read that report.
(3) Mitchell Tsai's answer to How long does CoV19 last on surfaces? This isn’t up-to-date. There’s newer data on clothing and insides/outsides on masks.
Hypothetical data from a soap and COVID-19 study would look like:
5 seconds soapwashing with X% soap: 80+/-5% COVID removed from hands, 50+/-20% deactivated
20 seconds soapwashing with X% soap : 90+/-2% COVID removed from hands, 75+/-5% deactivated
We would then make an informed decision to choose
(a) an amount of soap (X%)
(b) an amount of time to wash (vigorously or lightly).
Instead the amount of time we are supposed to wash hands is 20 sec.
Why? Many soap studies use 40 or 60 seconds of washing.
Real data = Real advice
No real data = Guessing
Also good would be a measurement of active & inactive virus left on sinks, faucets, and handles.
Now why did I post these contradictory things here?
To make you think about these things ....
Correlation isn’t causation
Even the experts can blindly repeat what others say without checking the facts themselves
In cases of desperation, we cling to all sorts of straws available, without giving our brains much work
Even experts differ in their perceptions and assessments
What we follow depends on what our perceptions are, not on what facts are