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The specific lab employee may not have even known they were infected. Many cases of Covid are asymptomatic. They may not even remember that they went to that we
by jmpman 2y ago
The specific lab employee may not have even known they were infected. Many cases of Covid are asymptomatic. They may not even remember that they went to that wet market on the way home from the lab. Just because we don’t have a smoking gun now 4 years later, doesn’t mean that this wasn’t the cause.
Again, go with the “wild” scenario in which a lab worker in the only lab in the city (country? World?) which studies Covid, got infected, and went to the wet market, just 800M away, and infected other people/animals.
Now, given that’s the reality in this “hypothetical” scenario, what would the data look like when analyzed by the talking heads in the YouTube videos?
Again, they would come to the same conclusion - that it was impossible. And you would still say that satisfiability and reality are orthoganal, even though, in this hypothetical scenario, this was reality.
Clearly their brilliant deductive approach would have been wrong in this scenario, and your dismissal would have been equally wrong.
Now let’s talk about another scenario, in which the Covid epicenter started not in Wuhan, but in some wet market in Laos. No Covid research center within 800M of this wet market. No Chinese government trying to avoid international embarrassment of causing the pandemic, and attempting to cover up. Would I suggest that a researcher from the Wuhan Covid lab caused the infection in the Laos wet market? Of course not. In that scenario, naturally infected animals are the most likely cause. But, just for amusement, let’s think about the reality where it actually was caused by a worker in the Wuhan Covid lab. They got infected in the lab, travelled 2000 miles to Laos, went to this specific market, and infected some people and animals in the market. In this scenario, that’s the reality. The person had to travel for likely days, and not infect anyone else. The person likely only had dense public transport to get from A to B. They would have encountered thousands of people, for a collective tens of thousands of “interaction hours”, and nobody else got sick. The probability of this happening is extremely low.. but in this scenario is did happen.
What’s the difference in these two scenarios? The distance and time to travel between the Wuhan lab and the respective wet markets, which then results in more interaction hours, and the number of times a worker from the Wuhan lab visits each of these wet markets. How many times has a Covid Lab worker visited a random wet market in Laos? Once? Twice? How many times has a Wuhan Covid lab worker visited the specific wet market 800 meters away from the lab? I’m going to go with more than once or twice. Probably thousands of times.
I don’t live in Wuhan, or any city likely close to the same density, but I can walk out my front door, and walk to one of two coffee shops. One is 500 meters away, the other 800 meters away. There are some days in which I can walk to the coffee shop and not pass a single person. There are other days in which I pass 50 people. It takes roughly 5 minutes to walk to either coffee shop and the interaction with each of those 50 people take less than 2 seconds, for roughly 100 interaction-seconds. During the entire Covid lockdown, I make this walk daily, likely passing people with Covid, and never got infected.
An infected Wuhan Covid lab worker could walk from the lab to the wet market, and not infect anyone along the way.
While they were in the lab, wearing their faulty PPE which allowed them to get infected, their coworkers were properly using their PPE and were protected.
The worker walked to the wet market, infecting nobody along the way, because it was a walk outdoors, and there was a breeze, and it was an unusually empty time of the day, and he/she only passed a few people and only briefly.
- kelseyfrog 2y agoCarving out a geographic region of zoonosis improbability around virology centers is not unbiased. That's the issue with starting with "it could have been any wet market," and then subtracting "but it couldn't be wet markets around virology centers," because then it would be "virology centers." Probability doesn't work like that.
- tripletao 2y agoI'm not sure what you mean here? The presence of the world's biggest collection of novel sarbecoviruses in Wuhan doesn't decrease P(Wuhan|natural), but it does increase P(Wuhan|research-related). So it absolutely should change your estimate of P(research-related|Wuhan) in the obvious way, unless your prior for a research-related pandemic is zero. I don't see how that prior could be zero, since the 1977 flu pandemic already killed ~700k people and is uncontroversially accepted to be of research-related origin. The arguments today are much more sophisticated, though. The debate that you linked relied heavily on Pekar's "The molecular epidemiology of multiple zoonotic origins of SARS-CoV-2". It took those conclusions at face value, apparently since nobody on the other side had the mathematical skills to go deeper. But not only is their fundamental approach questionable (why would you trust a model that complex with no opportunity to validate it?), but their implementation was filled with careless mistakes: https://pubpeer.com/publications/3FB983CC74C0A93394568A373167CE#6 https://pubpeer.com/publications/3FB983CC74C0A93394568A37316... https://gillesdemaneuf.medium.com/backstage-story-the-oct-2023-correction-to-pekar-et-al-e167080e957d https://gillesdemaneuf.medium.com/backstage-story-the-oct-20... They partially addressed this in their erratum, but made minimal changes to the language of their conclusions despite the Bayes factors changing by factor of ~10.
- kelseyfrog 2y agoAssuming P(Wuhan|natural) and P(Wuhan|research-related) are mutually exclusive, exhaustive, and sum to unity then can you explain how one probability can increase without the other decreasing? If the presence of virology institutes lowers the probability of zoonotic spillover then a great defense against zoonotic spillover is simply building a bunch of virology institutes.