Contaminated surface has under 1 in 10k chance of causing an infection
cdc.gov
cdc.gov
These are typical surfaces found on public transport, shopping malls, food courts. Three days allows for a lot of traffic to pass through and potentially come into contact with the infected surface. Of course, if the infection is coming from someone who is at that location on a daily basis (works there, takes the same bus/train each day) then the 3 days stretches out because surfaces are getting re-infected while the person is infected. Given that in densely populated areas such locations can get hundreds to thousands of people passing through each day, 1 in 10K may still translate to 1 infection every few days for a given "location". Each of those people would likely infect whoever they cohabitate with. So, while surface transmission is very low, it's not nothing, and can translate to real numbers in short order.
You may read the above and say "so what?". I should point out that I'm based in Australia, and the way we've handled the COVID situation and the numbers we've had and are having, means we are generally pretty highly sensitised to avoiding the kind of shitshow happening in most of the rest of the world. The numbers you are seeing in your countries are horrific to most of us.
Nobody is perfect but certainly our previous leadership did a great job of proving just how critical it is that world leaders understand or at least believe in science and facts.
I've seen some Australian news outlet coverage via YouTube and can draw some pretty close parallels to a well known news outlet ironically named after a clever animal in the US. In my mind, this means the seeds of misinformation and a rise in the same kind of political environment are quite possible there too.
I remember Zeynep Tufekci ranting about a school where they had strict procedure for doing a weekly deep cleaning, but no guidelines on ventilation.
Obsessively cleaning bags from the grocery store and cereal boxes may not be the explanation for why your COVID experience seems saintly compared to contiguous regions with 10x the population and 40-50x the population density.
Not saying it isn’t horrific out here, but not all of us live on a desert island in Oceania. :/ Greenland has faired even better than AUS but I doubt it’s because they have better surface disinfecting practices, just less surfaces and people in general compared to AUS.
All of this. So many people are holding up AUS and NZ as the way the rest of the world should have handled it. But as you correctly say, they're two isolated countries on the bottom of the planet, no land borders, no ferry traffic from neighbouring countries, low population density, and also largely self sufficient.
Stopping people entering and leaving AUS/NZ is trivial versus Europe or the USA. Shut down your borders for months and you've solved the problem. Do that in the USA or Europe, and you'll have empty shelves and chaos.
I live in Melbourne and went through 2 multi-month lockdowns. The first was 3 months, the second was 5 months. It may be comforting to think that it was "trivial" for us to control the spread of COVID, but I assure you it didn't fucking feel trivial 5 months into the 2nd lockdown.
I wrote that it is trivial to prevent people entering and leaving AUS/NZ, as you also stated in your comment "We shut our borders to people (mostly) not goods."
I did NOT write it was trivial "locking down" cities. Europe is under going similar lockdowns, so Australia is far from alone. According to the press, there are 30-40,000 of your fellow citizens that still have not been able to return home 12 months after all this started, precisely for the reasons above.
> population density of the whole country is irrelevant.
It's completely relevant. Even more so that if you live in Perth, you don't just jump in a car and drive to, say, Sydney, whereas in Europe you can drive from London to Birmingham in a couple of hours, or Paris to Brussels, and so on. Australian towns and cities are very widely spread compared to Europe and the USA. Which is reflected in the speed of transmission (and lack of) across the country.
[1] https://en.wikipedia.org/wiki/File:COVID-19_Outbreak_World_M...
Surface has been contaminated * chance of transmission * chance of dying
All three are (for most people here) similarly small numbers. Do you want to spend your time doing something that can save you with probability < 1/(10^15)?
The idea was to keep Covid out, any other contaminant you think you're getting rid of has already breached your security. In fact, bactericide usage will select for stronger and more resistant bacteria.
What you need is a clean room, otherwise it's a futile exercise.
the relative risk of fomite transmission of SARS-CoV-2 is
considered low compared with direct contact, droplet
transmission, or airborne transmission 1, 2. However, it
is not clear what proportion of SARS-CoV-2 infections are
acquired through surface transmission.Also it doesn’t stand to reason that you treat each item in your grocery delivery as having disjoint probability of harboring infectious virus. That’s clearly not true in the real world.
To be honest i massively underestimated how often i touch some of these items in the first few days, coffee jars alone get touched 40+ times, jam and butter 12+, bread 18+, diluting squash 14+. even if i wash my hands after stowing away and subtract that number I'd probably be left with an average number of touches well over 6 after stowing.
-To be honest i massively underestimated how often i touch some of these items in the first few days, coffee jars alone get touched 40+ times, jam and butter 12+, bread 18+, diluting squash 14+.
I mean, it's not nothing, but I wouldn't say "practically guarantee".
p(a') = 1 - 1/10000
1 - p(a')^14400 = 0.76308930063962
Now a 1/10k taken twice is 2/10k, so taken 14 thousand times it is 14k/10k. Okay so this isn't technically how you add statistics, but its close enough to see the utility in washing items.
It's a flawed analogy, I admit, but with the parcel you would have to palpate its entire surface and lick the finger after every touch to infect yourself. Just touching it for the second time doesn't double the chance of infection. You may touch the same uncontaminated part you'd touched already (crossing the same numbers twice), the number of virus particles you've moved might not be enough to infect you, that you might have washed your hands in between the touches, and so on... Obviously, the more you "interact" with an item the chances grow, but certainly not as fast as you suggest. Add a time limit to all of that, and the fact that for every next item it's all back to 1/10k (second draw) - practically there's no way this number will ever grow over 1/1.
Excuse the non-fact-checked argument as I can't find a link now but I recently read that couriers and mailmen actually get ill less often than factory workers (and most of them caught the virus via airborne transmission). I don't mind if you wash everything you bring home from outside, but I don't see point in that, and certainly I wouldn't recommend that to anyone. It's wiser to focus on preventing airborne transmission than to waste time and efforts on avoiding the least probable risk.
> Findings of these studies suggest that the risk of SARS-CoV-2 infection via the fomite transmission route is low, and generally less than 1 in 10,000, which means that each contact with a contaminated surface has less than a 1 in 10,000 chance of causing an infection [7], [8], [9].
How is that not only misleading, but "very" misleading? The headline appears directly in the text almost word-for-word.
And the conclusion I drew from the headline seems about right. At worst, I think someone could miss the context of "each contact" with a contaminated surface, but I still wouldn't call this very misleading.
EDIT: I mean if an infected postman gives you a package what is the ratio that you will get infected by direct contact versus the surface of the package? Assuming you won't wash your hands. 10:1?
Better (and based on the text): Few SARS-Cov-2 transmissions reported to have been via surface transmission.
And note: However, it is not clear what proportion of SARS-CoV-2 infections are acquired through surface transmission. Probably not many.
“SARS-CoV-2 and Surface (Fomite) Transmission for Indoor Community Environments”
According to the article, that's probably risky if all of those thousands of surfaces are infected.
But you make a good point: I have no idea how many infected surfaces I touched last week/month/year.
Note the paper suggest the real rate could be lower. For instance, a 10^-5 risk per contact would mean <0.4% risk for 365 contacts.
I haven't seen a single case of reported surface transmission.
There was this case in a New Zealand quarantine hotel, where they first suspected a rubbish bin lid, which the persons had touched 20 hours apart. But now they think it was air moving, by opening the hotel room door from the room to the corridor, and then to the next room, when that door was opened right after.
https://www.theguardian.com/global/2021/apr/04/how-new-zeala...
Businesses have "installed" sanitizers and clean a bit more often. Correct air ventilation is mostly too costly, too inconvenient or outright impossible. But since the business is already doing _something_, "complying", there is a false sense of security.
(Sorry for just pasting a link, but I think it’ll be more clear than any summary I could make.)
1. Basic safety principles mean that as long as we're not sure, keep doing it
2. You may have been enjoying a year surprisingly free of common colds, of flus, and many more other illnesses. These are absolutely transmitted through surfaces, and increasing hygiene standards is the best way to get rid of them.
Keep washing your hands you filthy animals.
There are diminishing returns in this caution principle, while the harm caused by the deluge of disinfection products on the environment and ourselves certainly adds-up.
You can never be 100% sure you won't get infected through surface. By this logic you should spray sanitizers everywhere all the time.
Disinfecting and cleaning your hands (even with soap. Noone's told you to douse your hands in alcohol every hour of the day) is as much for your protection as it is for others. Additionally, you can expect an average person to wash their hands maybe three to four times a day. Considering we have doctors and nurses that do this on the order of tens of times a day (and they all do it with hydroalcoholic solutions, which is the one thing that will damage your hands), the pretend harm caused to ourselves is bullshit.
My main concern really is the over-cleaning of surfaces. Those products are nasty.
There is little debate in the matter.
I would even bet that most people issuing the cleaning guidance know that it is almost useless, but we live in a world in which it is more important for your actions to make you perceived the way you want rather than being effective.
Shouldn't store B then be spending less money on "sanitary theatre" and can theoretically provide a marginally better service in ways that matter?
The federal government can spend however many billions of dollars for new TSA staffing and equipment, but that's because they're a monopoly in airline security. Not sure why in a free-market we'd have obviously sub-optimal outcomes like this.
(Sorry if this is naive, feel free to weigh in with harsh realities about how the real world works :) )
I don’t agree with that as a way to run policy that affects real people living their lives.
Because scientific guidance already involves debate within the scientific community, just with people actually qualified to debate it.
It seems some people are taken aback by their exclusion, but no one is stopping you from becoming a virologist and partaking in the debate.
Who were you thinking would be left to debate those guidelines when the guidelines are based on the debate of experts?
Guidelines change because the experts are still free to debate them, where there is little room for debate is following the results of said debate.
-
And what on earth are you asking me how the guidelines from virologists went for when you're the one arguing for leaving room for debate against them?
One would imagine you'd have some very clear pictures of missteps that can't be excused by the fact we were trying to fight an unknown virus killing people at an alarming rate if you're saying there's room for debating if we should follow their guidelines.
I mean go look at the evolution of discussion on COVID fomite transmission yourself.
In March we were getting studies showing long lived presence of COVID in some form on surfaces for weeks, but there was debate on if those were actually infectious amongst experts.
By April here's a virologist pointing out that the results showing weeks didn't mean it was infectious:
https://www.forbes.com/sites/coronavirusfrontlines/2020/04/0...
And for those who will not read the article but will try to respond based on the url... the conclusion was still supporting possible transmission, just for days instead if weeks. And it was still recommending aggressive disinfection:
> This suggests that risk of infection from virus on objects or surfaces in the environment can be minimized by diligent cleaning and disinfection practices.
-
The very nature of the guidelines is including the fact no all experts are going to agree, which is the point of an organization like WHO.
There is little room for debate in following what their guidelines. It's very easy to come up with armchair opinion showing how misguided that is where they were wrong, but their recommendations are based on accounting for the fact we had a global pandemic to deal with.
How do you think the science is done? The first step is to debate these things, to figure out possibilities and design experiments.
And how this new information is supposed to reach everyone without being twisted? I heard so much crap being said by doctors, scientists, professors etc. Not just hyperbole, and assumptions, but downright misinformation. I'm in Poland and since the beginning of the pandemic there were multiple lies coming from both government ministers and all the people representing "science" I mentioned. Some examples of lies:
"Masks don't work to protect normal people",(later)"a piece of cloth is all you need", "children don't transmit the virus(then when a new wave of infections was partially caused by children returning to in person learning - ok we fucked up, children were infecting people all along, but we need parents at work not sitting with their children at home) ", "incidence of infection in the workplace is low (then after few months data came out showing 40% of all infections are in the workplace) etc etc.
Now a year later same" leading scientists" are still being invited by the media to answer questions. All available media lie more or less. In this environment how a "typical" person is supposed to know the truth?
I can find published research articles in reputable journals, and actual data to find out what is true, but I have no idea what advice to give to my friends and family who don't have that capability. When they ask me how do you know what is true. All I can say is "read everything and make up your own mind" which is pretty poor.
Everyone can do the math. With 100 contacts to contaminated surfaces the chance of infection grows to 0.01. If the chance to become infected per contact are just 1/2000 with 100 contacts the chances of getting infected are now 40%.
It makes perfect sense to maintain surface hygiene since those contacts accumulate statistically.
Actual risk is likely much lower, as you have to touch contaminated surface, then transfer the virus to nose, mouth or eyes. For public areas, properly worn masks help prevent part of the transfer too, by making it mechanically less likely, and giving more time for evaporation to inactivate the virus (e.g. by airflow)
Fomite infection risk would be higher if a contaminated surface is brought to a presumed clean area, with low ventillation, with no additional precautions taken by people.
P(getting infected per touch) = 1/10000 = .0001
P(not getting infected per touch) = 1 - P(getting infected per touch) = .9999
P(not getting infected after 100 touches) = P(not getting infected per touch) ^ 100 = .9999 ^ 100 =~ .99
P(getting infected after 100 touches) = 1 - P(not getting infected after 100 touches) =~ .01 = 1%
Or, in other words:
1 - ((1 - .0001) ^ 100) =~ .01 = 1% chance of infection
By the same logic, your second estimation is a bit off:
1/5000 = .0002
1 - ((1 - .0002) ^ 100) =~ .02 = 2% chance of infection
That's a far cry off 40%.
To think about it another way, if the chance to get infected per touch is 1/10, and you touch a surface 20 times, is your chance of infection 200%? No, that doesn't make sense. It's 1 - ((1 - 1/10) ^ 20) =~ 87.8%.
That's the problem with statistics -- "everyone can do the math", but it's pretty easy to mix it up and reach the wrong conclusions and spread misinformation.
This sounds like gamblers fallacy to me. The number of trials doesn’t change the probability of individual trials in this case because each trial is statistically independent, I saw no mention of e.g. accumulating viral load via successive surface contacts.
From the article, emphasis mine:
> each contact with a contaminated surface has less than a 1 in 10,000 chance of causing an infection
And it isn't. We know that the infection happens when enough active viruses appear on the mucosa cells of the host. We know that there are a lot of viruses in every droplet from somebody's nose or mouth. Imagine how much viruses somebody leaves on the surface if he wipes his nose with a hand, for example, and then uses that hand to handle some item.
Finally, we know how much time it takes for half of the viruses to become non functioning (half life) -- something like three days, it is, they remain in the similar numbers for quite a while on the surface. Multiple touches of the same surface on which there is certain number of viruses is nothing like a series of "independent trials."
Not in my area. That is, scientists here would beasically say: we don't know yet how well surface transmission works, so better take precautions. Which in hindsight still is the best approach in my opinion. Took a couple of months (IIRC) before it became well-accepted that chances (while existing) were fairly low. Not sure, but 'free and open' debate sounds like you want to have laymen have their say in things like this which is, again in my opinion, a bad idea. Only biologists/chemists/virologists/... have the fundamental knowledge it takes to reason about this without making mistakes. And between them there definitely was a debate, and they came to the same conclusion.
How is that possible?
And I'm sure that not all came to the same conclusion. You can probably find some that think 5G is a major contributor. But a broad consensus forms, where people start to think of surface sterilization as somewhere between "not important at all" or "only mildly important" as a measure to prevent COVID spread.
But the precautionary principle means, until the evidence is in--- maybe using protective measures that are effective against other viruses is a sane thing to do until we know more.
No, but you also didn't specify the people taking part in the debate. So I just tried to interpret it and suggested 2 possibilities.
All biologists/chemists/virologists came to the same conclusion?
How is that possible?
Because it makes most sense. Note that the conclusion was not "the virus spreads by surface all the time". It was: "we don't know for sure (which was completely correct at the time), so better safe than sorry".
Those two assumptions don’t make sense to me, sorry.
I wanted to have heard from the biologists/chemists/virologists who had it right from the start. I don’t recall hearing all sides of the issue. Somebody out there surely saw this coming.
Actually I am not assuming anything. I clearly said I wasn't sure, which leaves the possibilities open.
assuming that every biologist/chemist/virologist came to the same conclusion
Not really, because I don't know every single scientist. I am still talking about the ones in my area. A couple of which I've talked to and those all agreed. And again: the conclusion at the start was not "there is high risk", it was "we do not know how high the risk is". The default mode of scientists is "we do not know" so I hope you see it's pretty easy for a group of scientists to all agree on that. Much, much easier than agreeing on something else because that requires thorough research. But basically you are right on this one: I obvisouly do not have hard evidence all possible scientists agreed they didn't know the actual risks for surface transmission, I just assume they all admit that.
I don’t recall hearing all sides of the issue.
There are many factors which influence that of course. Media in general can be problematic passing through everything.
Somebody out there surely saw this coming
Of course, but that still doesn't mean those people wouldn't agree with "we do not know for sure".
All that really bought me was seeing the 'debate' was between people that knew far less than the little I knew. Worse what most of what they thought they knew was wrong.
The big mistake was assuming that this new virus is just like this other virus they were more familiar with. Lay people and a lot of doctors used influenza as a model. Wrong. People who knew better thought the virus would behave like a not as bad SARS-Covid1 or MERS. Also wrong[1].
My conclusion a year ago was the best strategy was to take all the precautions until further notice. I thought of the doctors quip that the problem with medicine is half the treatments we give patients doesn't work. The real problem is we don't know which half. Taking all reasonable precautions then is always the correct answer.
[1] Public heath officials in the west[2] assumed that SARS-Covid2 only spread between symptomatic people like MERS and SARS-Covid1 does. That bit them on the ass but hard.
[2] Public health officials in China highly suspected asymptomatic transmission early on. But western officials categorically dismissed Chinese researchers opinions. (Big mistake #2)
Paper: https://www.nejm.org/doi/full/10.1056/NEJMc2001468
Story: https://www.nytimes.com/2020/06/27/world/europe/coronavirus-...
https://www.washingtonpost.com/goingoutguide/playground-safe...
Whilst there's no doubt you could catch from touching a surface, it's a respitory disease that you catch by breathing in water droplets contaminated with the virus.
Wash your hands, fine. Leaving your shopping in the garden or spraying with bleach? Seems a touch hysterical to me. And I say that as someone that was in a high COVID area, grocery shop frequently, and still haven't caught it from touching a tin of beans on a shelf.
> They are hiding, scared, waiting for the government to officially announce that it is once again safe to return to the world.
If it were a leveled discussion of facts, without the obvious agenda and judgment attached, people would not react so negatively.
Would you believe that many of us are not scared, but rather that we decided based on facts about aerosol transmission that nonessential travel/social events put other people's grandparents at unneccesary risk?
The winning move actually is not to play the social game for a few months. Currently, the best people are the ones you do not meet at all.
Doing it in a snarky way is particularly not cool.