Some people get the virus. Some don't. There are hotspots in enclosed spaces.
A theory of virus spread: Viral load.
The dose matters.
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| NY Subway. Share the air. |
So what are the risks?
There are theories that attempt to integrate the data. One is that humans seem to be able to shrug off small, incidental contact with the virus, but that when there is high viral load from physical contact or breathing large amounts of the virus, people get it. Then they take it home to family members, who get it.
Yesterday I was in a farm supply store. The staff all wear masks. I wore a mask but almost none of the other customers do. (This is rural, agriculturally oriented, pickup truck Trump country. They think this whole thing is a hoax, Democratic tyranny Trump-hating over-reach.) It is a big open store with high ceilings, and not particularly crowded in the aisles or checkout area. A mask-less customer about fifteen feet down the aisle from me from me sneezed. I immediately left the store, going the opposite direction from the sneezer.
Everything I wrote above is relevant to whether I will catch the virus.
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| Restaurant spread |
We observe virus hotspots, where infection spread widely to a discrete group of people. An infected person goes to choir practice and sixty people spend two hours in a large room, members having been careful to stay a distance from one another and not shake hands or hug. They breathed deeply as they projected their voices singing. Forty five of the sixty people in the choir were infected and two died. Singing spread virus.
People working closely in vigorous work in multiple meat packing plants spread the virus to one another. People attending weddings and funerals catch the virus from one infected person. Restaurant patrons sitting and talking at the table or downwind the HVAC air flow from an infected person's table gets the virus, while people upwind do not. Suggestive data.
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| This customer: Hand sanitizer, no mask |
Normal breathing projects a little virus. Coughing projects much more, approximately 3,000 droplets spread more widely. Sneezing projects an enormous amount--30 thousand droplets with 200 million virus particles.
The time of exposure to virus infused air seems to matter; more time around the virus means more load. The store employees at the farm supply store are at more risk than are customers, since they have a shift's worth of exposure while shoppers come and leave.
The article suggests it is probably low risk to shop for brief periods in a large uncrowded store with high ceilings and lots of air space for each shopper, if one avoids a cougher or sneezer. Ventilation matters and being in another's personal space matters. Proximity and time are key. Under this theory, personal care people are the most at risk themselves, and the riskiest to be around. They are close to other people's breaths. Do you really need that haircut?
Certain places are more dangerous than others. Public bathrooms tend to be small, enclosed, and have multiple touch surfaces: handles, doorknobs, latches. Viral load goes from surface, to hand, perhaps to car keys, to eye or face, to licked lips: a high viral load.
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| CDC paper: restaurant ventilation matters |
Is the viral load theory correct?
We don't know.
It does explain why it hit densely populated New York City, close workplaces, and religious and other affinity groups. It seems to explain the choir and workplace hotspots. It would explain why rural places like Jackson County Oregon with wide open spaces, airy grocery stores, and people traveling in cars and not subways, would have zero new cases for three weeks. We have natural social distancing, except in senior housing, where strict rules are in effect.
It does explain why it hit densely populated New York City, close workplaces, and religious and other affinity groups. It seems to explain the choir and workplace hotspots. It would explain why rural places like Jackson County Oregon with wide open spaces, airy grocery stores, and people traveling in cars and not subways, would have zero new cases for three weeks. We have natural social distancing, except in senior housing, where strict rules are in effect.
Still, it is just a theory. There may be other factors. Possibly some people or strains of the virus are simply way more infectious than others. That could explain hotspots
The viral load theory gives policy makers and individuals some guidance about how to mitigate risk. Classrooms are close clusters of people in spaces with desks and other high touch surfaces. Restaurants put people together at tables where they face one another to talk, also risky. Parks and spread-out outdoor events are perhaps low risk because concentrations of the virus are low.
In day to day life, under this theory one considers everyplace to be a little "dirty" but some air and objects more "dirty" than others. It may not be dangerous for a shopper to breath the air in a grocery store or to be handed a receipt printed by the store's register, but the stainless steel bowl into which coins rattle when getting change has been touched by dozens of people, some of whom may have covered their sneezes with their hands. That is "dirty." Don't touch anything until you have washed your hands. Don't hug. Don't get close to another person's breath.
It could be that the way to think of the virus is that a little virus won't kill you or your customers. If it did, you and they would already have gotten it and have died. Perhaps the key is to avoid giving or getting a big dose.
6 comments:
Another big factor is how often you expose yourself. If one goes out daily it's seven times more likely than once a week, etc.
I don't know what to think about those who still think the epidemic or the response is a hoax or some kind of conspiracy to control us. Wearing a mask in public, even here in relatively "safe" Medford has been explained as the reason we are safe, as is staying home and washing groceries.
Social distancing scofflaws are having their fun, but if (or when) the cases start mounting again it may be time for more draconian measures to keep people from infecting themselves and more importantly, others.
I'm all Libertarian if you're not threatening me with your behavior.
We're all on our own. I suggest daily doses of vitamins C and D as self-protection.
Trump has obviously been negligent in botching a national testing strategy and provision of personal protective gear for doctors and nurses.
But Democrats have not proven themselves to be a viable alternative.
Tough to know whose negligence has killed more New Yorkers - Trump, or Cuomo's order to nursing homes that they MUST take back residents who had been treated for COVID19 in hospitals (Democratic governors in Pennsylvania and Michigan issued similar orders, with similar deadly results). Or De Blasio's early-March tweet telling New Yorkers to go to the movies, even giving them a movie recommendation.
America will go back to work and the virus will kill as many as it kills. We have no leaders, no functional culture, that could create any other possibility.
Let's face it, we live in a world where medical science takes a back seat to the funding of a deadlier nuclear weapon. And perhaps some of the unelected critics should be reminded that its very easy to criticize the actions of our local leaders in dealing with the Corona virus when actions, or lack of thereof, may result in deaths. We are burdened further by being politically naive. We proved that here in southern Oregon, where with the support of the local paper we were represented by a self-serving man for twenty years. A man who left no legacy, a man who stood for nothing in the way of improving the lot of his fellow man. Because of the seniority system in Congress whereby committee chairmanships are awarded on the basis of seniority, the southern states have benefitted greatly by returning the same career politician year after year.(The longest serving boob, usually a Southerner, thereby wields the power to send Federal dollars to his bailiwick) But even after 20 years, Greg Walden secured no such benefits for the citizens of southern Oregon. He was not there to reprseent our interests but rather his own. And now we have the spectre of Jimmy Crumpacker, the revolting Republican carpetbagger from Portland, eager to take over by capitalizing on the votes that elected Walden for those twenty wasted years.
Bob Warren
There is no way we can shut down the spread of the virus by testing and contact tracing. It is too widespread in this country. There was never any hope of that regardless of the hindsight that political actors on both sides indulge themselves in.
What we can do is limit its spread and “flatten the curve“ so that our medical facilities and personnel are not overwhelmed.
And we need to start reopening the economy, because failing to do that would also cost lives.
We need to find an optimal tradeoff, not insist on one side of a binary choice.
Posted here on behalf of Thad GuyerMy chances of dying of virus are next to nothing"
On my daily bike ride today, at the little place where I sit on the seawall near the golf course, I chatted with a golfer over the age of 60, he plays a foursome with others of his age. I was wearing a mask he was not. "My chances of dying of the virus are next to nothing" he explained when I ask why no mask. "That is a statistical fact", he said, and of course it cannot be disputed. Even by the worst case scenario projections, a white healthy person of any age like him who does not live communally with poor people or old people faces a chance of dying of "next to nothing". "If I get exposed my immune system will defeat it after regular flu symptoms, and I will move on". This too is not controversial.
Worst case scenario if we do not do social distancing has been put at about 5 million people. Even if it was three times that the golfer would still be right that his chances of dying of the virus are "next to nothing". His chances of dying, or yours, of the virus are many multiples closer to zero percent than even 10 percent.
"So why do you wear the mask, and if you are so afraid why are you out here bicycling and stopping and chatting with people", he asked. I answered that I agree with him that my chances of dying of the virus since I don't live in a crowded big blue city apartment or a nursing home are approximately 0%. But I said "I would feel stupid without the mask, and the disinfectants, should I find myself laid up in the hospital".
You see, I simply don't want to be humiliated in death. But I am in favor of throwing open the economy as broadly as possible and letting each individual make their own decision. I am an Oregonian, you have a right to die! You may be my brother's keeper, but I certainly am not. But even if I were, I have a shockingly low level of reliable empirical information to tell anyone else what they should do.
The virus is not a hoax. The assertion that you will probably die of it if you don't do what the government says, is .
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I have a different take from others on several points.
First: it’s not only what chance we have to die from the virus. Have you read about the horrendous damage some get to their organs that can affect them the rest of their lives? May not be a high percent. Doesn’t matter to me — because I don’t want to live that way. I don’t want to risk whatever chance there is for that — just because I want to go back to the way it was, or don’t like wearing masks, or whatever arguments the folks use who say they shouldn’t be told what to do. (My daughter had it. No permanent damage. But she said the cough was the worst she’d ever had, and she felt like her throat was being torn apart. She was isolated for 3 weeks on her bedroom.)
Second: it’s not just about us. And our “rights” to do what we want with our bodies, take our risks. Some (on FB) have said, “If you’re afraid, stay in.” But I don’t think of myself as afraid so much as rational. And their view is that of a bully. Think about this. If a bunch of people decided they wanted to swing bats around when ever they were out amongst people, and they should be free to do it, how would we react? Their rights stop at my nose. If they say, stay in if you’re afraid, them they’re asserting their supremacy, the “rights” of people who are physically powerful and don’t care if they hurt others. The potential victims need to lock themselves away. Nope, read the law-related definition of assault. It’s not just physically attacking someone, but doing something that threatens a person physically. This virus is unpredictable. The “right” to get close to people without wearing a mask means the right to threaten them. Not all would feel threatened. Doesn’t matter. It’s actually an ‘unnecessary’ risk. (vs. the necessary risks normal people must take to live.)
Third: Remember, this virus is new — and it has acted in unusually dangerous and unpredictable ways. We think it affects some groups and not others... until we learn we’re wrong. We think it’s just if we’re sneezed or coughed on — until we learn just talking towards a near person can do it. We think we don’t have it/ can’t stress it unless we have symptoms. Then we find at people can so read the largest viral loads before symptoms show. We said, “but is it a high fever? And found out not everyone gets a fever at all. Right now! We don’t know enough to be taking unnecessary risks because we “aren’t afraid” or don’t think we’re in a high risk group. We don’t know how much immunity or how long it might last from having recovered from it.
Fourth: Do we have any concern for others? We don’t wear our masks for us. We wear them for each other. If you have the virus and don’t know it, you could be spreading it to someone vulnerable. Who are you willing to kill? Your grandpa? Your grandchild? Your friend with heart disease or breathing difficulties? Or ... men friends — who have a higher mortality rate for the virus than women? Wear a mask. Stay your distance. Don’t make excuses. This won’t last forever. Practice patience. Remember when people risked their lives for others — and that’s not being asked for from us.
Lastly: Yes, there are problems tied to the shutdowns. Some people suffer from anxiety having to stay home most of the time. I’m an extrovert. I’m a hugger. I feel lost! Tough. I’ll talk to friends on the phone, attend church on zoom, and pop some marijuana mints. Some are affected financially. We should support help for them. We should share our money from the government if the virus hadn’t affected our income negatively. (Don’t know if you’ve heard this, but many have committed to donate the whole amount eve gave ours away before we got it. ). We can come back from an economic downturn, but not from death. And... if we foul it up, the restrictions — and financial damage — will be even worse. So... let’s encourage everyone we have influence on to take this seriously.
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