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I have been hearing a lot of people say that it is recommended to wash your hands thoroughly in order to maximise protection against COVID-19 infection. I also heard that the washing hands rumours are just a way to make people believe that they are protecting themselves and that the washing hands thing is actually not backed up by real data.

Question:

Is washing hands really that useful? And if yes, is there any data backed up to defend this?

The reason i'm asking this is because an expert in this field said that the "data is very week behind this" and "it's not going to have a big impact on preventing infection" (https://www.youtube.com/watch?v=E3URhJx0NSw) 43:32 and that the data behind the virus being infected through the eyes is very sparse (https://www.youtube.com/watch?v=E3URhJx0NSw) 44:00

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    You do realize that hand washing as a disease prevention method has been firmly established since the 1800s, right? It's a rock solid medical fact and I'm not going to watch a 90 minute video to see someone question it. Please at least provide the time mark in the video where he makes these statements. – Carey Gregory Mar 13 at 15:15
  • @CareyGregory so sorry, i thought the links already included the time. Edited – The Poor Jew Mar 13 at 15:19
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    His comments seem to suggest he thinks its only transmission route is airborne, but I've seen no evidence to support that. Most respiratory viruses are spread by droplets and by viruses on the hands being transferred to common surfaces (door knobs, handrails, etc). There is ample evidence showing that hand washing is highly effective against such transmission routes. – Carey Gregory Mar 13 at 20:00
  • Is this question more suited to skeptics? – Graham Chiu Mar 18 at 5:48
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Here's an article that I found helpful, to understand why washing hands with soap is so helpful, and how it helps (Pall Thordarson is a professor of chemistry at the University of New South Wales, Sydney):

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.

When you cough, or especially when you sneeze, tiny droplets from the airways can fly up to 10 metres. The larger ones are thought to be the main coronavirus carriers and they can go at least two metres.

These tiny droplets end on surfaces and often dry out quickly. But the viruses remain active. Human skin is an ideal surface for a virus. It is “organic” and the proteins and fatty acids in the dead cells on the surface interact with the virus.

When you touch, say, a steel surface with a virus particle on it, it will stick to your skin and hence get transferred on to your hands. If you then touch your face, especially your eyes, nostrils or mouth, you can get infected. And it turns out that most people touch their face once every two to five minutes.

Washing the virus off with water alone might work. But water is not good at competing with the strong, glue-like interactions between the skin and the virus. Water isn’t enough.

Soapy water is totally different. Soap contains fat-like substances known as amphiphiles, some of which are structurally very similar to the lipids in the virus membrane. The soap molecules “compete” with the lipids in the virus membrane. This is more or less how soap also removes normal dirt from the skin.

The soap not only loosens the “glue” between the virus and the skin but also the Velcro-like interactions that hold the proteins, lipids and RNA in the virus together.

Alcohol-based products, which pretty much includes all “disinfectant” products, contain a high-percentage alcohol solution (typically 60-80% ethanol) and kill viruses in a similar fashion. But soap is better because you only need a fairly small amount of soapy water, which, with rubbing, covers your entire hand easily. Whereas you need to literally soak the virus in ethanol for a brief moment, and wipes or rubbing a gel on the hands does not guarantee that you soak every corner of the skin on your hands effectively enough.

So, soap is the best, but do please use alcohol-based sanitiser when soap is not handy or practical.

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    Rule of thumb: alcohol-based sanitizers work on enveloped viruses like COVID-19 and herpes, but not on non-enveloped viruses like polio, rhinovirus (common cold), and HPV. Soap works on everything. Bleach works on everything. – Charles Mar 19 at 21:04
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Yes, the virus can be made un-harmful by soap and water. From the Economist:

The outer proteins sit athwart a membrane provided by the cell in which the virion was created. This membrane, made of lipids, breaks up when it encounters soap and water, which is why hand-washing is such a valuable barrier to infection.

This should give you enough key terms to read further about why this is effective.

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There are obvious sufficient data and enough evidence that all virus are transmitted by droplet infection (body contact) and shake hands. Washing hand makes sense as the infection is happening mostly yourself if you have contact with your hands in your face, mouth, nose, eyes.

So don't shake hands, clean your hands by washing or desinfecting after touching the cars and bags in a supermarket or any other objects, as you can transport a virus with your hands in body openings - as everybody touches his face may be 100's of times a day unconsciously.

https://www.healthline.com/health-news/how-to-not-touch-your-face

In normal times we can be overprotective to ourselves. "More dirt" could be an option or devise in education, but not in times when schools and kinder gardens have to be closed because of an epidemia or a pandemia.

https://www.medscape.com/viewarticle/926373

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    Thank you for your answer, but the answer I'm really looking for should be backed up by research publications. ie publication whether the virus can infect people through their eyes or from contact of hands containing the virus. The reason i'm asking this is because an expert said that the "data is very weak" behind this. youtube.com/watch?v=E3URhJx0NSw – The Poor Jew Mar 13 at 9:04
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    actually "we" don't know very little - but covid19- also named SARS-2 - is similar to SARS 1 - there is evidence that it is also in a similar way transmitted, but even faster, as it can be reproduced already in your throat and not only from lunge to lunge. If you doubt that there exist studies you can consider the epidemia in Italy or China as the biggest field study we ever had. thelancet.com/action/showPdf?pii=S1473-3099%2820%2930144-4 – Albrecht Hügli Mar 13 at 9:20
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"Situations Leading to Reduced Effectiveness of Current Hand Hygiene against Infectious Mucus from Influenza Virus-Infected Patients", a study published in "MSphere", compared using "antiseptic hand rubbing" (hand sanitizer) against "antiseptic hand washing" (washing hands with antiseptic or antimicrobial soap), and found that washing hands is effective at killing the Influenza A virus.

"Reducing viral contamination from finger pads: handwashing is more effective than alcohol-based hand disinfectants", a study published in the "Journal of Hospital Infection", found that hand washing for 30 seconds is effective against MNV1 and noroviruses.

"Epidemiologic Background of Hand Hygiene and Evaluation of the Most Important Agents for Scrubs and Rubs", a study published in "Clinical Microbiology Reviews", found that "simple hand wash reveals the best results compared with other possible hand treatments".

I believe that these findings, plus other research, have been generalized to all viruses, including COVID-19.

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There is a report from Taiwan where it was described that installing hand wash stations in the emergency department was the only infection control measure which was significantly associated with the protection from healthcare workers from acquiring the SARS-CoV, indicating that hand hygiene can have a protective effect

Healthcare workers are at risk of acquiring a SARS infection while caring for SARS patients. Many rational ICMs were implemented to protect HCWs during the panic of the SARS epidemic. For example, NPIR, PPE, and hand washing were all implemented by each hospital as required by the health department. However, nosocomial transmission still occurred despite the above-mentioned measures [1,5,6,14]. Yen et al. formulated the concept of traffic control, an integrated infection control strategy involving triaging patients (using barriers and zones of risk) and checkpoint spots for hand washing [7]. Traffic control was shown to significantly reduce the rate of SARs in HCWs (0.03 cases/bed vs HCWs in other hospitals 0.13 cases/bed) during the 3-week study period [7]. However, there were limitations in the study; the authors were unable to demonstrate that traffic control was the key factor in reducing the number of HCWs acquiring the SARS infection. Understanding the causal relationship is important to validate the effectiveness of each ICM among so many integrated measures.

Our analysis showed that the timing of the ICM implementation was critically important. Hospitals in which HCW SARS transmission did not occur implemented ICM B earlier than those experiencing SARS transmission to HCWs (Figure 1). The hypothetical causal relationship model between the ICMs and the HCWs acquiring SARS was supported by our SEM analysis in which the following ICMs were the causes of preventing SARS transmission: traffic control in the ED (including triage on patients with fever of unknown aetiology, increasing installation of hand washing facilities in the ED, bleach disinfection performed after cross-contact in patient transfer, and mandatory body temperature surveillance), installation of a fever screening station outside the ED, availability of an outbreak standard operation protocol, mandatory body temperature surveillance in hospital, hand washing setup at each checkpoint in the hospital, standardized patient transfer procedure, availability of a simplified isolation room. It appears that successful control of SARS infection is not based on an individual measure, but on the integration of several measures.

Installation of a fever screening station outside the ED was the most important factor, and contributed 51% of the effectiveness towards the prevention of SARs in HCWs. During the SARS epidemic, as patients overwhelmingly flooded into hospitals and caused chaos within the ED [6,18] it was rational for each hospital to screen the patients outside the hospital. The outside fever screening station was first developed by the Singaporeans [19]; this was done in accordance with the ancient concept of quarantine against the black plague during the 14th century. Our finding quantitatively validated this approach. The fever screening station acted as the security guard in the front line of protection.

The second most important factor was the traffic control measures in the ED (19%). HCWs in the ED are at the front line of contact with SARS patients and the most likely to be infected [6,18,20]. The environmental survey also found a high sample positive rate for SARS coronavirus RNA in the ED [6]. Our finding validated the need to protect HCWs in the ED using traffic control, as this is an important factor for protecting all HCWs from hospital-acquired SARS. The retrospective observation also confirmed our finding that the nosocomial transmission of SARS in Taiwan declined significantly after the implementation of traffic control in the ED of hospitals as mandated by the Department of Health. By implementing traffic control in the ED, direct contact of SARS patients and contamination of the environment can be minimized by screening patients with fever, transferring and isolating patients, and disinfecting the environment.

Hospital management is important since it affects the other factors associated with protecting HCWs from SARS, including availability of outbreak standard operation protocols (12%), mandatory body temperature surveillance in hospital (9%), hand washing setups at each checkpoint in hospital (3%), availability of a simplified isolation room (3%), and standardized patient transfer protocols (3%). During the SARS epidemic, body temperature measurement and hand washing were encouraged spontaneously, and the compliance rate was higher during the non-epidemic period. Standardized outbreak control and patient transfer procedures were part of the hospital standard operation protocols. Hospitals with better management are less likely to have HCWs acquiring SARS or any other nosocomial infections. The Six Sigma process may be implemented into the hospital infection control procedures to prevent further unknown infections [21–23].

https://www.journalofhospitalinfection.com/article/S0195-6701(20)30046-3/fulltext

Quantitative evaluation of infection control models in the prevention of nosocomial transmission of SARS virus to healthcare workers: Implication to nosocomial viral infection control for healthcare workers https://www.tandfonline.com/doi/full/10.3109/00365540903582400

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