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Contaminated surface has under 1 in 10k chance of causing an infection

cdc.gov

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Re: Contaminated surface has under 1 in 10k chance of causing an infection

#101

Post by 1_player »

baud147258 wrote: post #97
turing_complete wrote: post #91

Earlier quoted context omitted.

Opportunity cost. Keep in mind that those conditional probabilities multiply: 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)?

I think the idea is that you're cleaning not just Covid-19, but also any other kind of contaminant

There is bacteria everywhere in your house, on your skin, inside of you, on every single surface on planet Earth.

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.

Re: Contaminated surface has under 1 in 10k chance of causing an infection

#102

Post by sokoloff »

baud147258 wrote: post #97
turing_complete wrote: post #91

Earlier quoted context omitted.

Opportunity cost. Keep in mind that those conditional probabilities multiply: 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)?

I think the idea is that you're cleaning not just Covid-19, but also any other kind of contaminant

People largely weren’t doing this 18 months ago and many started doing it around 12 months ago; what changed their mind?

Re: Contaminated surface has under 1 in 10k chance of causing an infection

#103

Post by pbourke »

cortic wrote: post #98
abtinf wrote: post #55

Earlier quoted context omitted.

“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.”

120 items on my average delivery, assuming a driver or stacker is infected that could mean every item is contaminated. I touch them 1-2 times to put them away, 3-4 times as i open and use the items.. So that could be 720 'touches', and that may be cheating as i am counting my many fingers as 1 and i don't live alone. So each contaminated delivery could risk infection as much as 1 in 14 (10,000/720). Through this pand…

Do you also sanitize your door knob, handle, pantry door handle, fridge/freezer handle, faucet controls, etc? Merely washing your hands when you’re done stowing items seems to be a better strategy.

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.

Re: Contaminated surface has under 1 in 10k chance of causing an infection

#104

Post by bgarbiak »

cortic wrote: post #98
abtinf wrote: post #55

Earlier quoted context omitted.

“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.”

120 items on my average delivery, assuming a driver or stacker is infected that could mean every item is contaminated. I touch them 1-2 times to put them away, 3-4 times as i open and use the items.. So that could be 720 'touches', and that may be cheating as i am counting my many fingers as 1 and i don't live alone. So each contaminated delivery could risk infection as much as 1 in 14 (10,000/720). Through this pand…

I’m not sure you can count the probability this way. Each touch is a separate event, and for each touch you have 1 in 10000 chance of infection. So, it’s 1 * 720 / 10000 * 720.

Re: Contaminated surface has under 1 in 10k chance of causing an infection

#105

Post by approxim8ion »

elisaado wrote: post #86
approxim8ion wrote: post #67

Earlier quoted context omitted.

Yeah, same. It's kind of become a mindset now, and the way I see it, the habit is a net positive so I will likely retain it for years to come.

Care to tell me how it is a net positive? What kind of germs/virussus are you cleaning off that you wouldn't have come in contact with in the grocery store itself?

I was mostly talking about deliveries, but fair point.

Re: Contaminated surface has under 1 in 10k chance of causing an infection

#106

Post by acqq »

sixstringtheory wrote: post #93
fsloth wrote: post #17

Earlier quoted context omitted.

One in 10k per contact is still non-neglible imo. 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.

> the chance to become infected per contact are just 1/5000 with 100 contacts 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…

That thought, that "the number of trials doesn’t change the probability of individual trials in this case because each trial is statistically independent" is based on a false assumption that the mathematical statement, observed alone, is all we know about the issue.

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."

Re: Contaminated surface has under 1 in 10k chance of causing an infection

#107

Post by bryanrasmussen »

pengaru wrote: post #96
bryanrasmussen wrote: post #42

Earlier quoted context omitted.

the point was that the brown m&ms have an important signalling effect? and I said well there could be a case in which the signal you thought you were receiving from the m&ms being present was wrong?

The point is only to detect whether they read enough of the contract to find that buried, arbitrary but highly visible detail, not to ensure they execute everything within it.

In the versions of the story if they didn't execute that point Van Halen's roadie would go on the warpath and go through everything to determine stuff was done correctly, so I mean the point was not that they read the contract? No one cares if you read the contract, they care that you do what is in the contract - of course doing what is in the contract requires that you read it first, but it is the doing that people care about. If you have not done the M&Ms correctly you have not read the contract that means you could not have done the important things they require.

Re: Contaminated surface has under 1 in 10k chance of causing an infection

#108

Post by sampo »

asplake wrote: post #20

Not a great headline. What if I touch thousands of surfaces? 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.

> Few SARS-Cov-2 transmissions reported to have been via surface transmission.

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...

Re: Contaminated surface has under 1 in 10k chance of causing an infection

#109

Post by aksss »

phs318u wrote: post #29

"Data from surface survival studies indicate that a 99% reduction in infectious SARS-CoV-2 and other coronaviruses can be expected under typical indoor environmental conditions within 3 days (72 hours) on common non-porous surfaces like stainless steel, plastic, and glass." These are typical surfaces found on public transport, shopping malls, food courts. Three days allows for a lot of traffic to pass through and pot…

You had me nodding along until last paragraph, where I can’t help but ask you to remind me what the population of AUS is, and the population density. Aren’t you also on an island with relatively harsh immigration policies?

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.

Re: Contaminated surface has under 1 in 10k chance of causing an infection

#110

Post by cortic »

pbourke wrote: post #103
cortic wrote: post #98

Earlier quoted context omitted.

120 items on my average delivery, assuming a driver or stacker is infected that could mean every item is contaminated. I touch them 1-2 times to put them away, 3-4 times as i open and use the items.. So that could be 720 'touches', and that may be cheating as i am counting my many fingers as 1 and i don't live alone. So each contaminated delivery could risk infection as much as 1 in 14 (10,000/720). Through this pand…

Do you also sanitize your door knob, handle, pantry door handle, fridge/freezer handle, faucet controls, etc? Merely washing your hands when you’re done stowing items seems to be a better strategy. 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.

I sanitize the items in the garage, as i fill a sanitized crate, then my hands, then lift them into the house. Its quick and easy, it also allows me to reduce contact with the driver.

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.

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