First off, you should definitely wash your hands or use hand sanitizers to defeat the Coronavirus.
That having been said, it isn’t always possible or practical to do that. Sometimes I’m on the road. And all I can do is splash on some water. Is that enough? Or is it at least better than nothing?
It might be helpful to note, viruses, and deadly viruses in particular, live in what is known as a symbiotic relationship with their human hosts. On some strange level they need us, and we need them. So they simply aren’t that virulent. Or else they’d kill off all their hosts. So usually it is relatively easy to kill them on surfaces. No?
I’m rather confused about when it couldn’t be possible or practical to reach in your pocket or purse, pull out the bottle of hand sanitizer you carry everywhere you go and use it.
Carrying and using water sounds like more effort and I can easily see where it wouldn’t be possible or practical to splash water around.
Viruses are not living organisms. They are a genome with a capsid (protein shell) and sometimes a lipid viral membrane which enters the cells of a living organism to replicate and for some to inject genetic material into the host genome. They are not symbiotes, and the reason they don’t survive well on surfaces is because they desiccate and break down into component proteins and amino acids. There are plenty of viruses that are virulent; prior to eradication, Variola minor, the vaccine that caused smallpox, had a mortality that was upward of 30% even in populations evolved with regular epidemics, and estimated to be in excess of 90% in the native populations of the Americas.
“Splashing on some water” does almost nothing. The point of using soap is that it mechanically removes virus, not that it kills it. We’re supposed to scrub our hands for 20 seconds not because that length of time kills the virus but because that much scrubbing removes most of the virus. Soap is much more effective at doing this than water alone.
If you don’t have hand sanitizer or soap, but do have water, rub your hands together under the water and dry them with a clean towel or air dry. Rubbing your hands under water will rinse some germs from your hands, even though it’s not as effective as washing with soap.
Note that this is only recommended as a “better than nothing” strategy to be used when you’re in a pinch. Also note that this is considerably more than just “splashing.”
Carry hand sanitizer with you. Buy one of the small bottles that fit in your pocket. When there’s no soap, scrub hands with water for at least 20 seconds, dry them, and use hand sanitizer. There’s no excuse for not doing this.
The other thing to realize here is that despite early messaging, coronavirus is largely spread by breathing in particles of various sizes, not by contamination of hands. So, sure, use some water without soap. It’s not as good as using soap, but it also probably doesn’t matter very much.
The continued focus on handwashing has likely been to our detriment. Not because handwashing is useless, but because there are many higher impact things you can do, like getting better masks (most people are still wearing cloth masks), staying out of buildings with other people and opening windows for better air circulation.
Aerosol transmission is the primary mode because for a pathogen that can be airborne it is a really easy to transmit from person to person, but that doesn’t mean that hand sanitation is not necessary or worthwhile. If you are wearing a good filtering non-woven mask correctly, getting infected by touching a contaminated surface and then touching your face or a food item is the next most likely mode of infection. However, your point that focusing on the wrong things is well-taken; early in the pandemic we saw some nations ‘santizing’ outdoor spaces with fumigants and antibacterial sprays that a) don’t disable viruses, b) may leave residual traces that can cause respiratory aggravation that may actually make people more prone to infection, and c) are pointless because virions that are outside in open, relatively dry air will rapidly desiccate anyway. The key measures to reduce transmission aside from mask-wearing and personal sanitation are, as you note, reducing indoor contacts and improving ventilation in buildings.
One of the frustrations I’ve had is watching even public health authorities take ineffectual and potentially even counterproductive measures like closing outdoor dining or parks despite the copious evidence that well-spaced outdoor contacts present an almost negligible likelihood of transmission and give people venues to meet under the best conditions for preventing spread. Instead, by closing off these outlets, it has caused people to meet indoors in private settings, both contributing to spread of contagion and not modeling or reinforcing good hygiene practices. And of course, it is inevitable that any number of these authorities and politicians get caught out violating the guidelines that they’ve advocated for because they just aren’t practical (e.g. Gavin Newsom at French Laundry or Deborah Birx traveling to a family gathering). I get that public health authorities are basically turning the few knobs they have legally available to control public behavior but they should really be modeling and encouraging low risk behavior by example, especially given how long such strictures are going to have to be imposed.
It’s likely helped reduce the flu we usually get this time of year. The only thing I’ve heard about the flu this year or last is that it’s way down from the usual. All the measures we’re taking for COVID are also helping with the flu. Well, most of them. As Stranger points out, the sanitizing of outdoor areas was a big waste of time and effort.
That phrase “Aerosol transmission” is sometimes used as distinct from “droplet transmission”.
Droplet transmission is the primary mode, and is blocked by masks and social distancing.
There is another form of transmission, involving aerosols that can remain suspended for hours and drift from room to room, which is less common. It is believed that this is less common, because if it was more common, we’d all be sick by now. It is believed that it exists, because sometimes people get sick who were only present later, at a distance.
But isn’t it also believed to be the method of infection for those who wear masks and practice social distancing? It seems that at least the mask wearing part is far more common than its opposite.
You’re half right: Not only does soapy water help to mechanically remove the virus from your skin, but it also attacks the lipid membrane on the virus itself, causing its destruction.
This is why hand sanitizers work. They don’t wash away the virus, but they do attack its lipid membrane; it’s just that they do it with alcohol instead of soap.
I am not confounding aerosol and droplet transmission. Aerosol transmission is a primary mode of infection of SARS-CoV-2 and is the reason that there is so much “community spread” among people who do not share households or are in direct contact with a known infected person.
There was denialism of an aerosol mode early in the pandemic by the US Centers for Disease Control and especially by the World Health Organization despite ample evidence of transmission that could only be explained by aerosol transmission. “Super spreader events” in particular are evidence of aerosol transmission outside of a food preparation environment or swimming pool/sauna because of how difficult it is to transfer pathogens to multiple people who are not otherwise in intimate contact.
SARS-CoV-2 is higher in the lungs compared to the upper respiratory tract (Zou et al., 2020). This is consistent with smaller aerosolized particles being emitted from the lungs. Infections with a higher viral load in the upper respiratory tract may be more likely to be droplet spread. A cough can produce approximately 3000 droplets while a sneeze releases about 40,000 (Dhand and Li, 2020), most of which were small droplets (1–10 μm). During normal breathing and talking, 80–90% droplet sizes are <1 μm that are subject to aerosol transport (Morawska et al., 2009). Since breathing and speaking occur more frequently than coughs and sneezes, they have a critical role in viral transmission, particularly from asymptomatic cases. For COVID-19, the average virus RNA load in oral fluid was 7 × 106 copies/mL (Wölfel et al., 2020), but some patients may exceed that by more than two orders of magnitude. There is a 37% probability that a 50 μm droplet prior to dehydration contains at least one virus, and this probability is reduced to 0.37% for 10 μm droplets (Wölfel et al., 2020). Although very few particles actually carry viruses, the number of small particles far exceeds the number of larger sized droplets (Wölfel et al., 2020; Rothe et al., 2020). By using a laser light scattering observation, at an average viral load of 7 × 106 per mL (Wölfel et al., 2020), 1 min of loud speaking could produce thousands of oral droplets per second, of these at least 1000 virus-containing droplet nuclei that could remain airborne for more than 8 min (Stadnytskyi et al., 2020). Thus, these are likely to be inhaled by others and hence trigger new infections.
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For the second criterion, the viability of SARS-CoV-2 has been demonstrated experimentally in air and on surfaces. As a hypothetical example, after 7 days, SARS-CoV-2 could still be found viable on the outer layer of a surgical mask (22 ℃; relative humidity 65%) (Chin et al., 2020). SARS-CoV-2 can survive for more than 3 h in the air, with a half-life of 1.1 h in aerosols (21–23 °C; relative humidity 65%) (van Doremalen et al., 2020). A more recent study found a UK variant of SARS-CoV-2 could remain viable in aerosols for at least 90 min under experimental conditions (artificial saliva and tissue culture media) (Smither et al., 2020). Another study suggests SARS-CoV-2 in respirable-sized aerosols could persist and maintain infectivity for up to 16 h (Fears et al., 2020). Santarpia et al. have reported measuring viable SARS-CoV-2 in air collected in hospital wards with COVID-19 patients(Santarpia et al., 2020), which consistent with detection of airborne SARS-CoV-2 RNA in patient areas. Altogether, these results indicate that SARS-CoV-2 could survive in aerosols for a relative long time under favorable conditions and potentially spread through aerosols.
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For the third criterion, epidemiological studies are difficult to interpret with respect to role of transmission unless other routes can be ruled out. In particular, when people are close together, they can be simultaneously exposed to an infectious disease through multiple routes. However, by analyzing the trend and mitigation measures in Wuhan of China, Italy, and New York City of USA, a recent study indicated airborne transmission contributed to the spread of COVID-19 (Zhang et al., 2020). Some outbreaks of COVID-19 in which aerosol transmission may have a role are summarized in Table 1 . For example, on Feb 3, 2020, in Inner Mongolia of China, a case of COVID-19 was reported in a person who passed the door of a symptomatic patient several times but did not have direct contact, suggesting airborne transmission (Wang and Du, 2020). Another study compared risks of COVID-19 outbreak among 126 passengers taking two buses (59 from Bus #1 and 67 from #2) on a 100-minute round trip in Ningbo, Zhejiang Province (Shen et al., 2020). Compared to individuals in the non-exposed bus (Bus #1), those in the exposed bus (Bus #2) were 41.5 times more likely to be infected. Evidence from this outbreak suggesting airborne transmission of SARS-CoV-2, particularly in this closed environment with air re-circulation and no contact between passengers. Air-conditioning ventilation also explained the aerosol transmission of a outbreak among diners at adjacent tables following the direction of airflow in a restaurant at Guangzhou, China. The distances between patient zero and patients at other tables in this outbreak were all >1 m, and in the review of video records from the restaurant, no evidence of direct or indirect contact were found between the three parties (Lu et al., 2020).
Ok. In Australia, the ‘denialism’ still exists, because if aerosol transmission was the primary mode of transmission, our hotel quarantine system and lockdowns would not have worked at all.
We’ve just had an outbreak linked to aerosol transmission, which has re-emphasized the point.
Handwashing has likely reduced COVID at least a little, given one mechanism of infection is thought to be “get germies on your hands, then rub your eye / suck your thumb / pick your nose”. As a substitute for masks / distancing, vs an adjunct, oh hells no.
Back in October, I actually did the “splash water” approach: I was driving from DC to Vermont, stopped to get gas, tried to use the restroom - and it was out of order. No way to wash up - and hand sanitizer isn’t as useful if your hands are actually visibly dirty. I had brought a 2 liter soda bottle, filled with water, and was very happy to be able to stand beside my car and get rid of the surface grime. Dunno if I rinsed away any viruses but it kept me from going nuts the rest of the trip.
A related question: I loathe the feeling of hand sanitizer. I won’t refuse to use it if asked, of course, but my hands always feel tacky afterward. Is it still working after it dries? My tendency is to wash my hands with water afterward (if I can) but am I basically destroying any benefit to having used it?
By the time it dries, it’s done doing everything it can. When sanitizer dries, the active ingredient is evaporated away.
Unless you’re doing something to force the sanitizer to evaporate much faster, it’ll be in contact with any viruses stuck to your skin long enough to do the job long before it dries off. Although I’d love to see hard evidence of how long is long enough.
Isopropyl alcohol is a very effective solvent for lipids and it will essentially break down the M-protein (membrane) of coronaviruses on contact. There are some viruses that are more robust (specifically noroviruses like the Norwalk virus) but coronaviruses in general are not that durable in the environment.
If you saturate your hands (palm, fingers, and back down to wrist) with alcohol and leave it until it evaporates (20-30 seconds) it should deactivate essentially all of the coronavirus you might have on your hands. Wetting your hands slightly before applying hand sanitizer actually improves the solvent action of isopropyl alcohol on bacteria, and washing your hands after letting hand sanitizer dry does nothing to reduce its effectiveness once it has sterilized your hands. Soap and water is more effective yet but obviously not as convenient as bottled sanitizer.
Last year was actually a somewhat worse flu season than usual. The peak of flu season was before COVID and its associated mitigation efforts really took off, so they didn’t have much effect on it.
This year, though, flu has absolutely been way down, because, yes, most of the things we’re doing to protect against COVID also protect against flu. And a lot of other diseases.
That’s the difference between good hand sanitizer and bad hand sanitizer. Almost all of the stuff on the market meets guidelines for effectiveness, but there are a lot of newcomers on the market that don’t have much experience making skin products, and a lot of them feel really gross. I’m fortunate that I still have a supply of pre-COVID sanitizer (I realized a few years back that it was much cheaper to buy it in bulk), and so I carry my own with me everywhere and use it preferentially to what others provide, for that reason.
I was thinking of the reports from the southern hemisphere when I mentioned last year’s flu season. The flu season in Australia and NZ was almost nonexistent, IIRC.
We had a presentation in the preschool where I work, and we got a sort of hierarchy of things to do the get COVID off our hands. #1 was washing thoroughly under running water, with a soap that had a certain anti-microbial ingredient, the name of which is eluding me.
Rinsing with clean water without scrubbing your hands together at length was actually less effective than wiping your hands thoroughly with a clean, dry towel.
Using a new, anti-“bacterial” (ie, microbial) wet wipe was more effective than plain water, even if it was running, and you scrubbed you hands together. But you really had to wipe, all over your hands, between your fingers, etc., for like, half a minute at least.
(bolding mine)
Unless the “antimicrobial” wipe also had antiVIRAL properties, you’d have done just as well to wipe with a damp towel for that same amount of time. I have to assume that’s what they meant, as an antibacterial wipe would do zilch against coronavirus. If anyone said “antibacterial” in that presentation, I sure hope someone raised the question and called them out on the terminology.
Interesting that a rinse under plain water is less effective than a plain dry towel (w/o pre-rinse). I’d be hard to convince that it’s worse than doing neither. I guess the real answer is to rinse your hands then wipe them off on your pants :).
“Antibacterial” or “antimicrobial” wipes usually contain a broad-spectrum toxin like alcohol, bleach, or an ammonia-based compound whose full name I can never remember, which are effective against pretty much everything, viruses included. I suppose that someone could make one with just a specifically antibacterial agent, but I don’t think anyone does.
