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Generally if someone only infects 1 person they're going to infect someone that they're close to. The lab leak of SARS-CoV-1 back in 2004 put two of the resear

Generally if someone only infects 1 person they're going to infect someone that they're close to. The lab leak of SARS-CoV-1 back in 2004 put two of the researchers in the hospital and killed the mother of one of the researchers. That is what a lab leak looks like. The two researchers had taken the train home and nobody really worried about that and there was no subsequent pandemic from that casual contact. So for SARS-CoV-2 you have to add up the probabilities for: 1. This researcher has never been identified [okay, its China so maybe they suppressed this] 2. This researcher did not infect anyone close to them [now you're talking about a lot more suppression] 3. This researcher infected one or more people at one site through casual contact [this is much more unlikely than people think] 4. That infection happened to be exactly in the location most likely for zoonosis (not at a bar, church, restaurant, shopping mall, etc or any other place in the city). [this is quite unlikely, now we're talking many thousands of possible sites] When you compare it against the coincidence that it spilled over in the same city as WIV that isn't going to actually be all that unlikely. You don't have the total area of China in your denominator for probabilities. The virus wasn't terribly good at replicating in humans initially and needed a city and not a rural population. Then you look at cities in southern/central china near where the bats are and the odds are probably closer to 1-in-12 than 1-in-a-million. It also isn't any coincidence that WIV was built closer to the bats and not in Beijing. So, SARS-CoV-1 spilled over in Foshan in the 12th largest city in China in Guangdong province, while SARS-CoV-2 spilled over in Wuhan in the 7th largest city in China in the Hubei province. Those are places you expect for a pandemic epicenter. As an exercise, roll 1d12 (or 1d20 if you're more skeptical) twice and if you get a '1' on either throw there's your coincidental spillover in the same city as WIV. A bit weird, but not even p < 0.05. Stuff like that happens.

Vecr 3y ago
> 1. This researcher has never been identified [okay, its China so maybe they suppressed this] > 2. This researcher did not infect anyone close to them [now you're talking about a lot more suppression] >3. This researcher infected one or more people at one site through casual contact [this is much more unlikely than people think] See, this is what I have a problem with. It assumes that the symptoms this person/these people had were bad enough for samples to be tested later (pretty much hospitalization at that point, or maybe a hospital visit if they saved samples for some other reason), and it assumes things about the transmission of the virus that I'm not sure were correct at the time. It's a different disease from SARS, it's demonstrably harder to track and contain. People don't need obvious symptoms to transmit, and by the time most people end up in the hospital the transmission probability has gone down, due to various things including better precautions, but mostly because their immune system has started clearing the virus. What kills people most of the time is off-target immune responses, not the virus itself.
- lamontcg 3y ago
  The SARS-CoV-2 early strains were pretty bad at transmitting. Most chains of infections actually died out. It was estimated that it took several introductions of the virus before outbreaks actually started. It still mostly infected people you had close contact with over a sustained interval. People who were out jogging weren't actually infecting the people they were running past, it was people in the same household, or people who were eating dinner together. And it is still quite severe and lethal once it finds a few people who are over 50 with comorbidities or anyone over 70 (it doesn't take anything particularly special to kill you if you're over 70). If the researchers were all in their 20s and never had any cross generational contact then it could transmit undetected, but people mingle across generations more than the average college student or young adult working in a FAANG/startup (particularly in China). And if you hypothesize cryptic spread then you have to explain the geographic clustering of the initial cases around the wet market. Now you have a worse problem because the lab worker gave it to someone who gave it to someone who gave it to someone else who somehow spread it in the wet market to make it look exactly like that was a spillover event and all the other chains died out without putting anyone in the hospital.

Vecr 3y ago

> 1. This researcher has never been identified [okay, its China so maybe they suppressed this] > 2. This researcher did not infect anyone close to them [now you're talking about a lot more suppression] >3. This researcher infected one or more people at one site through casual contact [this is much more unlikely than people think] See, this is what I have a problem with. It assumes that the symptoms this person/these people had were bad enough for samples to be tested later (pretty much hospitalization at that point, or maybe a hospital visit if they saved samples for some other reason), and it assumes things about the transmission of the virus that I'm not sure were correct at the time. It's a different disease from SARS, it's demonstrably harder to track and contain. People don't need obvious symptoms to transmit, and by the time most people end up in the hospital the transmission probability has gone down, due to various things including better precautions, but mostly because their immune system has started clearing the virus. What kills people most of the time is off-target immune responses, not the virus itself.

lamontcg 3y ago
The SARS-CoV-2 early strains were pretty bad at transmitting. Most chains of infections actually died out. It was estimated that it took several introductions of the virus before outbreaks actually started. It still mostly infected people you had close contact with over a sustained interval. People who were out jogging weren't actually infecting the people they were running past, it was people in the same household, or people who were eating dinner together. And it is still quite severe and lethal once it finds a few people who are over 50 with comorbidities or anyone over 70 (it doesn't take anything particularly special to kill you if you're over 70). If the researchers were all in their 20s and never had any cross generational contact then it could transmit undetected, but people mingle across generations more than the average college student or young adult working in a FAANG/startup (particularly in China). And if you hypothesize cryptic spread then you have to explain the geographic clustering of the initial cases around the wet market. Now you have a worse problem because the lab worker gave it to someone who gave it to someone who gave it to someone else who somehow spread it in the wet market to make it look exactly like that was a spillover event and all the other chains died out without putting anyone in the hospital.