I don’t want to come down against good hygiene practices, exactly, but my prior is that this is a completely unimportant change for most people to make. The waterline of sanitary practices in Western nations is high enough that increasing the frequency and thoroughness of the average person’s handwashing seems likely to be subject to serious diminishing returns.
Consider that we’re starting from a status quo where most people’s hands are washed 3-5 times a day, even if lazily. Yeah it’s not 100% effective, but I don’t think it has to be in most circumstances.
Is there good epidemiological data that estimates how many disease transmissions have insufficient hand hygiene as an important/necessary vector? Because I would bet that outside of unusual cases like food service and medical workers, the number is low.
“it’s not 100% effective, but I don’t think it has to be in most circumstances.”
Ineffective handwashing is basically useless other than removing visible dirt. The difference between doing a good job and doing a typical job is the difference between actually getting rid of the germs and preventing and infection or not.
“Is there good epidemiological data that estimates how many disease transmissions have insufficient hand hygiene as an important/necessary vector?”
Yes, and that’s why epidemiologists and health economists keep recommending people washing their hands, putting up posters to that effect, etc.
“Because I would bet that outside of unusual cases like food service and medical workers, the number is low.”
Yes, for food workers (who also do a bad job washing, and can’t/don ’t take time off when sick,) the impact is far worse.
Source: Forthcoming paper I wrote with Dave Denkenberger.
There’s enough variance that relative recommendations (“more often”, “more completely”, “more time spent”) are difficult to take seriously.
I wash my hands maybe 2-3 times per day and apply Purell (the brand provided at work) another 1-2. I don’t spend over 10 seconds, though I do try to get all surfaces. Will the marginal improvement of adding one instance or 5 seconds of additional scrubbing noticeably reduce my risk? I can’t find any study that has this level of granularity.
Is there good epidemiological data that estimates how many disease transmissions have insufficient hand hygiene as an important/necessary vector?
As opposed to what? Direct airborne transmission via breathing in droplets?
My model of the spread of colds and flu and so forth is that it is primarily down to bad hand hygiene. I’d predict (with pretty low confidence) that more people get infected through getting virus on their hands and then onto their face / into their mouth than by breathing in virus directly. I’ll look into this more when I get the chance, though, since lots of people are asking about this.
Droplets don’t usually float around very long. It seems most transmission would still require something going into a person’s mouth. A small portion of these droplets hang around in the air and can be breathed in, but poor hygiene seems like a far bigger issue given how often people touch their face, mouth, and food.
Also worth noting that, depending on the virus, particles outside a host can often survive for hours or sometimes days. To get infected by direct inhalation you’d need to be fairly close to a sick person when they were shedding virus into the air – i.e. to be very close to them in both space and time. To get infected through surface contamination the time requirement is much less stringent: you only need to be where an infected person was fairly recently. If you don’t have good hand/face/mouth hygiene, they can infect you without your ever seeing them or knowing they were there.
I don’t want to come down against good hygiene practices, exactly, but my prior is that this is a completely unimportant change for most people to make. The waterline of sanitary practices in Western nations is high enough that increasing the frequency and thoroughness of the average person’s handwashing seems likely to be subject to serious diminishing returns.
Consider that we’re starting from a status quo where most people’s hands are washed 3-5 times a day, even if lazily. Yeah it’s not 100% effective, but I don’t think it has to be in most circumstances.
Is there good epidemiological data that estimates how many disease transmissions have insufficient hand hygiene as an important/necessary vector? Because I would bet that outside of unusual cases like food service and medical workers, the number is low.
> Consider that we’re starting from a status quo where most people’s hands are washed 3-5 times a day, even if lazily.
Disagree, many people probably fall below this.
“it’s not 100% effective, but I don’t think it has to be in most circumstances.”
Ineffective handwashing is basically useless other than removing visible dirt. The difference between doing a good job and doing a typical job is the difference between actually getting rid of the germs and preventing and infection or not.
“Is there good epidemiological data that estimates how many disease transmissions have insufficient hand hygiene as an important/necessary vector?”
Yes, and that’s why epidemiologists and health economists keep recommending people washing their hands, putting up posters to that effect, etc.
“Because I would bet that outside of unusual cases like food service and medical workers, the number is low.”
Yes, for food workers (who also do a bad job washing, and can’t/don ’t take time off when sick,) the impact is far worse.
Source: Forthcoming paper I wrote with Dave Denkenberger.
There’s enough variance that relative recommendations (“more often”, “more completely”, “more time spent”) are difficult to take seriously.
I wash my hands maybe 2-3 times per day and apply Purell (the brand provided at work) another 1-2. I don’t spend over 10 seconds, though I do try to get all surfaces. Will the marginal improvement of adding one instance or 5 seconds of additional scrubbing noticeably reduce my risk? I can’t find any study that has this level of granularity.
As opposed to what? Direct airborne transmission via breathing in droplets?
My model of the spread of colds and flu and so forth is that it is primarily down to bad hand hygiene. I’d predict (with pretty low confidence) that more people get infected through getting virus on their hands and then onto their face / into their mouth than by breathing in virus directly. I’ll look into this more when I get the chance, though, since lots of people are asking about this.
Droplets would be number one on my list of transmission vectors for people other than the hand hygiene intensive cases I mentioned, yes.
Droplets don’t usually float around very long. It seems most transmission would still require something going into a person’s mouth. A small portion of these droplets hang around in the air and can be breathed in, but poor hygiene seems like a far bigger issue given how often people touch their face, mouth, and food.
Also worth noting that, depending on the virus, particles outside a host can often survive for hours or sometimes days. To get infected by direct inhalation you’d need to be fairly close to a sick person when they were shedding virus into the air – i.e. to be very close to them in both space and time. To get infected through surface contamination the time requirement is much less stringent: you only need to be where an infected person was fairly recently. If you don’t have good hand/face/mouth hygiene, they can infect you without your ever seeing them or knowing they were there.