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Comment by raz32dust | Hacker News Reader

> Which also makes me question about the effectiveness of lockdowns.

Lockdowns are definitively, absolutely effective in curbing spread. It is backed by solid evidence of reduction is spread in places where lockdown was implemented, AND we have logical scientific reasoning to explain why. The only debatable aspect is whether they are the best solution, given all the trade-offs. And that is a difficult choice. But given no other solutions, if you can afford a lockdown, it is the right first step while you figure out other options.

Countries have been able to avoid a lockdown if they have sufficient quarantine facilities, contact tracing and hospital capacity. But in the absence of these, lockdown is the most effective way to navigate this.

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Lockdowns were the wrong solution, imo. I think we've underestimated the spread pre-lockdown and the spread during lockdown (grocery stores etc.). We'll know once broad antibody tests are administered. But if the virus has already spread to 30, 40, heck 50 percent of the population, then what the heck are we doing in lockdown...

https://www.reuters.com/article/us-health-coronavirus-nether... 3% across Netherlands

https://www.bloomberg.com/opinion/articles/2020-04-24/corona... "in the most severely affected regions only about 10% to 15% of the population had been infected"

So, um, no, we are nowhere near the 50 percent, at least according to any data we might have. And, depending which expert do you heed and what is the definition of "herd immunity" they're after, we need 70%, 90% or 95% before this is over.

50-66% is most likely, and perhaps less. Estimates of R0 are mostly in the range of 2.0-2.5.

50% would lower a 2.0 R0 to 1.0. 66% would lower a 2.5 R0 to 1.0. And this ignores that we may have permanently changed behaviors (e.g. handshakes) that facilitate spread, so we may not even need this fraction to curb tramission.

New York City is presently somewhere past 23%, so that's a big chunk of the way to a 1.0 Rt without controls.

This is again missing the point. You cannot assume such things when lives are at risk. From the point of view of a leader, they knew the following:

- There is a deadly virus out there that is spreading very quickly.

- People who are not showing symptoms are spreading it.

- Community transmission has started

Given these data points, if one leader decided to lockdown sooner and another decided to wait it out, I think it is fair to say that the leader who picked lockdown made the right decision. Yes, if you add an additional data point that 50% of population is already infected, sure, you could argue that maybe it is doing more harm than good. But there is no evidence for this, and this almost certainly was not true when the lockdown decision was made in Washington and California.

What we were trying to do was to get the portion of the population that doesn't take this seriously to actually wash their hands, wear a mask (properly) in public to reduce their viral shedding and limit their trips out as well.

The why, as Washington State Governor Jay Inslee said, "The penalties are you might be killing your grandfather if you don't do it."

It's innocent others; our grandparents, those with known compromised health conditions, and those, even young and likely uninsured, with unknown health conditions, that are being saved.

Putting this another way, I don't care if someone is a smoker in isolation. That's their choice. I care when it spreads and affects others, including myself. The balance of freedom must be considered when conflicts exist, with a bias towards preventing tragedy of the commons.

> what the heck are we doing in lockdown...

Not overwhelming hospitals.

> But if the virus has already spread to 30, 40, heck 50 percent of the population

_If_ is the key part of this sentence. We simply do not know, which is why - as you point out - testing is key!

If we were strict on lock-down and on testing, we can be very effective with this:

After a few (say 6 or 8) weeks if lock-down we can know with high likelihood who is and who is not sick. Now test all the sick people (and their friends), and start testing the general public for anti-bodies. Then start tracing any new infections.

That requires folks following the lock-down and health measures and the mass availability of virus and anti-body tests.

So far, the highest estimates we are getting for antibodies are in the 20% range with dramatically flawed populations (NYC grocery).

Real number is less than that and could be way less than that.

Lockdowns create their own form of havoc, but I think they were the right decision at the time until we had more information.

Now we need to figure a low risk way forward

In addition, there's little doubt that the infection has spread far more widely in NYC area than elsewhere. The covid-19 death rate per capita in NYC is 3 to 20 times higher other areas of the U.S. So even if NYC area had 20% who had been infected, that would not mean the rest of the country was anywhere close to that; other areas would not be close to NYC infection rate unless there death rates were similar.

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