When I was in grad school, I was working on general game playing AI. Unfortunately, I was in a "pure logic" research group, founded on the old-school AI principles that believed AI could be derived from deterministic logic.
Of course, this limited the games that we could simulate to purely deterministic games (checkers, chess, go, etc.). Any games that included an aspect of chance required a hack like a "dice player" or a "deck player" that would add the random aspects of the game. Of course, this led to other problems, since the engines would try to calculate the current state of the game based on the "optimal" play of the random player.
This is a much more interesting approach, and I imagine will prove to be far more useful.
Many of the comments here seem to be missing the point. It is an object moving into the path of the car, and if the safety systems work as advertised, it should avoid that object. Whether it's a person, shopping cart, bike, go kart, etc. doesn't matter.
Barring concrete evidence that is the case, it's a very dangerous assertion to make. It would also mean that the transmissibility of SARS-CoV-2 is much higher than we originally thought, amongst those without "natural immunity".
Even if it were the case that half the population was naturally immune, we would want to understand why. The leading explanation at the moment is T-cells and previous exposure to other coronaviruses. Problem is, there's a good chance that previous exposures would be less likely in certain populations, like children, which could be especially problematic as we're debating sending kids back to school.
At the very least, we need more data on T-cell prevalence/reactance to SARS-CoV-2 before we can jump to the conclusion that people are already immune.
But right now, it's far more likely that we've seen drops because of the drastic measures that have been taken and the changes in daily behavior across the population.
The distinction comes down to factors that change (behaviors, mandates, regulations, etc.) and those that don't (age, gender, etc.).
Saying we've reached herd immunity given behavioral changes is largely meaningless, as most people do not want to continue these behavioral changes indefinitely. One of the biggest changes that you failed to acknowledge is that people are not in contact with nearly as many people in their day to day life as they were before. Working from home, kids not in school, limited social interactions, etc.
It's not herd immunity if a return to previous behaviors negates the immunity.
> Back in February, Lipsitch gave a very rough estimate that, absent intervention, herd immunity might happen after 40 to 70 percent of the population had been infected.
Which is actually a mischaracterization of what the previous article[1] said:
> Lipsitch predicts that within the coming year, some 40 to 70 percent of people around the world will be infected with the virus that causes COVID-19.
At no point does he mention herd immunity. So, no, he's not saying herd immunity at 40%.
68% tested positive at a clinic in one neighborhood. Getting tested, without proper controls, is highly subject to self-selection bias. People were sick, couldn't get a test at the time, want to know if it was COVID, go in for an antibody test later. The people who were healthy, unless selected for a prevalence study, would much less likely to be tested in the first place.
Even in your first link, the highest percent positive is the Bronx reporting 33%. Not sure where you're getting 51% from, but it very much seems like you're trying to cherry pick data to support your argument.
Just because you and your friends weren't tested, doesn't mean the statistics are invalid. The link above was from random antibody testing and has a high confidence interval.
I've been sick twice during this time. Thought it had to be COVID, but two PCR tests and an antibody test all came back negative. Maybe the tests are flawed, sure, but it's far more likely I just had something else.
And even if mask laws are lifted and infection rates continue going down, it does not show that masks are ineffective nor that the OP was correct. After a mask mandate, some people will continue wearing masks and social distancing. As with immunity, the efficacy is in the numbers, with a critical mass necessary to protect the "herd".
Beaches are outdoors and while they make look crowded, people often maintain more than 6 feet between each other at the beach anyway.
The numbers are going down in Florida because people finally got a taste of how serious it is and changed their behavior.
The fact that you keep downplaying behavioral changes and completely ignoring other changes like people working from home and schools being out shows you are wedded to your conclusion. Unfortunately, it is fundamentally flawed.
You've made a extraordinary claim, the onus is on you to back it up with extraordinary evidence. A couple graphs of new cases going down and a photo of a boardwalk (where nearly everyone is in a mask) is not sufficient to support your claim.
I find it hard to believe, with the R0 numbers we were seeing initially, that 40% had a significant level of immunity. If the numbers were that high, then R0 among those without memory T-cell immunity would have been significantly higher, which suggests that the level of exposure/immunity necessary for herd immunity to set in would be significantly higher as well.
While true, that map and a photo of an outdoor space with people in it are poor pieces of data to hinge your entire argument on.
You completely failed to take into account people working from home, schools delaying opening and not having been in session since March or April, and all of the other measures that have been put in place to decrease transmission (masks, barriers, decreased social interactions, restaurant closings, other indoor spaces being closed, etc, etc, etc).
Your conclusion is flawed because you left all of these factors out of your analysis.
Also, the JHU map is a poor indicator, as they are clearly basing the colors on suspect data, as in this case in Nebraska, which apparently had negative new cases yesterday.
NYC had only 20% prevalence in mid-June[1], after they had contained the initial outbreak[2]. Therefore, the drop in new cases is very unlikely to be from herd immunity, which would need prevalence to be in the 80% range.
The author seems to ignore that most people are interacting with far fewer people because they are working from home, kids mostly aren't in school, and our other interactions with people outside our household have been limited and altered to decrease the chances of transmission.
It's nice to think that some people had memory T-cells that could deal with the virus, and it seems some people do, but based on the original R0 numbers, it would be foolish to think that is the case for enough of the population to conclude that we've reached herd immunity.
CDC Data from mid June had NYC at only 20% prevalence. Considering their low new daily cases since then, it's hard to believe they are anywhere near 68%.
Seroprevalence studies[1] in Italy, France, and Spain indicated we were a very long way off form herd immunity. They were in the range of 11-15%, where herd immunity would only start kicking in at about 70%. Based on cases per capita, the US might be 2-3 times higher than western Europe, but not yet at 70%.
I think the flaw in the piece is the author greatly underestimates the impact of the drastic measures we've taken to get those trends down. A lot of people are working from home, kids largely aren't back in school, and many of our other contact points outside of our households have been modified to minimize the risk of transmission. Seeing what happened to Israel when they reopened schools does not bode well for the US. [2]
Edit: NYC had ~20% prevalence in mid-June [3], after they had come back down from their peak. They've had many more cases per capita than anywhere else in the US, but their new cases have been flat since then, meaning prevalence has not increased significantly. Prevalence elsewhere in the US is likely in the 5-10% range.
1. Online learning is a poor substitute for classroom learning.
2. Online learning is much harder on parents and kids.
3. We're in the middle of a pandemic, in a country that has handled it very poorly.
4. Israel tried opening schools in May, when their daily new cases were at an all time low. New cases skyrocketed after opening schools [1], with nearly 50% of new cases being traced back to schools[2].
5. Closing schools in the spring is estimated to have saved 40,000 deaths in the US[3]. At that time new daily cases were significantly lower than they are now.
Unfortunately, classrooms undo a lot of the measures that have kept new daily cases from going significantly higher. They create contacts between families that would not have been in contact otherwise, and as new data comes out, it's clear that children are just as contagious as adults.
With what we know, as hard as it is, I don't see how we can proceed with opening schools until new daily cases are much more contained. The alternative is to have a massive spike in new cases, have schools close again, and be in the same position with online learning, but with many, many more cases out there.
Of course, this limited the games that we could simulate to purely deterministic games (checkers, chess, go, etc.). Any games that included an aspect of chance required a hack like a "dice player" or a "deck player" that would add the random aspects of the game. Of course, this led to other problems, since the engines would try to calculate the current state of the game based on the "optimal" play of the random player.
This is a much more interesting approach, and I imagine will prove to be far more useful.