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Comment by gpmcadam | Hacker News Reader

As per CDC, survival rates by age group are as follows:

   0-19: 99.997%
   20-49: 99.98%
   50-69: 99.5% 
   70+: 94.6%

What would be the benefit for people 70 years or under taking vaccine that has "95% protection". Can anyone elaborate on what that figure actually means?

For example, of the <1% of people who would die with the virus, is a vaccine that is 95% effective going to save 95% of them? Or is this just about reducing severity for the few who have more than mild symptoms?

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95% protection means you get 95% less infections in a test group that got the vaccine compared to a placebo test group. It doesn't have much to do with the mortality rate.

But if you use that number on the whole population: Instead of a 5.4% mortality in 100.000 infected people of 70+, you end up with 5.4% mortality in 5.000 infected people of 70+, or basically having 270 death instead of 5400.

For the other age groups the mortality rate looks good, but "not dying" doesn't mean you're having a great time. A sizable amount of people end up in the hospital (in some places more than there are beds available), that costs huge amounts of money. So if we could reduce that by 95% there is going to be way less pressure on the hospitals and less costs.

Thanks for clarifying instead of downvoting. There's a lot of confusion about these numbers and it seems asking a question about them here is being taken as inherent criticism.

For HN that usually gets you upvotes. But apparently the virus is heavily politicised, particularly in America from what I can tell. So the result now is a thread full of dead/buried comments.

Thanks again.

No problem. I think a lot of people respond very strongly to the "mortality on young people is only 1%" data, because it can be taken as a reason not to take the virus serious.

Small correction: it means you get 95% fewer cases. People might still get infected, but never show enough symptoms to prompt them to get tested - and therefore never become a "case." This is the difference between "protective" (no disease) and "sterilizing" (no infection) immunity. The latter is the gold standard that you'd ideally like to shoot for, but the former is what the studies are actually measuring.

The distinction matters because there are vaccines (such as the original polio vaccine) that protect individuals against disease, but which still allow the vaccinated individuals to act as carriers and infect others. Those vaccines do not create herd immunity, because vaccinated people still contract and spread the virus. They do, however, protect the people who get vaccinated.

It means the population as a whole would have herd immunity (on average, every infected person would infect significantly less than 1 new person).

Result=> epidemic dies out.

Isn't that what happens now with normal exposure to the virus?

At huge societal cost. The virus has already killed almost 250,000 people in the United States.

Vaccines get you the individual protection (and eventually herd immunity) without all the death.

Right. We have about 3% of the US population who has had COVID, and 235,000 deaths. To get to herd immunity, we need about 50% of the population to be immune (exact numbers vary depending on the study). So to get there with the virus, we would expect around 4 million people to die in the US alone.

Not if you can get re-infected. That's why the cold and flu virus are still doing the rounds every year despite pretty much everyone you know having had a cold or flu at some point.

No, because for herd immunity to set in, far too few people have SARS-CoV-2 antibodies simultaneously (even if we let COVID-19 run rampant). That, in a nutshell, is the main reason why the “herd immunity”-based mitigation strategies are being dismissed by the vast majority of immunologists and epidemiologists. In fact, “natural” herd immunity (without the help of vaccines) might never have eradicated a single disease — at best, it leads to a temporary reduction in numbers.

The “standard example” for natural herd immunity eradicating a disease is the black plague, but most experts now believe that herd immunity isn’t actually responsible for its disappearance from Europe.

The protection figure is the based on the comparison between the people who received the placebo and people who received the vaccine. The group who received the vaccine had 95% fewer cases.

Also while improving the immune response of at-risk groups is of course important, the main goal is to reach herd immunity. Eg, if all the people _under_ 70 got the vaccine then the virus would never reach the aged care home in the first place.

And if those people under 70 were exposed gradually to the virus, they'd survive in higher rates than the vaccine? So would it be more effective to expose them to the virus instead?

By "expose somebody gradually to the virus" you're describing certain vaccine technologies.

Live viruses have a nasty habit of reproducing, spreading uncontrollably and killing a lot of people along the way. The people who survive do gain an immune response though.

Some virus technologies use "live-attenuated" vaccine, which are weakened (but living) versions of the virus which promote an immune response without causing illness.

No, the virus can kill and cause long term problems to people under 70, at a rate that would be unacceptable for any vaccine.

It could be a last resort solution if we had no hope of an effective vaccine, but it looks like the results are quite promising so far, so no need to go to such extremes.

"get people sick in a controlled manner" is a form of vaccination. Just a particularly dangerous kind, because you are using live viruses instead of non-infectious lookalikes. It is like training soldiers by putting them in real gunfights.

What are you going on about?

The vaccine doesn't kill you in the cases where it doesn't work.

If you are in the group with 0.5% chance of death without the vaccine, then with a 95% effective vaccine, you would have a 95% chance of being immune (0% chance of dying from the virus) and 5% chance of having the normal 0.5% chance of dying.

For my own self, I'm less concerned about mortality and a lot more concerned about lung and brain damage.

For society, I'm concerned about being able to get back to life without becoming an asymptomatic spreader.

This idea that only the deaths matter is mind boggling.

Beyond the damage the virus does without killing, there is also a massive pressure on health care. Keeping someone with a severe case of Corona (I think 5% of cases are this?) from dying requires a lot of care. I know that in my country (the Netherlands) this has caused significant delays to other forms of care.

Hence, even if people who get Corona get out without any long-term damage, their en-masse admission to hospitals still has long-term health effects. Just not on them, but on others that were denied care.

R0 would drop to nothing if they all vaccinated, pandemic over. Furthermore it's genuinely awful to have even if you survive it, and there is evidence of lung damage to healthy young survivors.

Lung and heart damage and very long recovery seem to be all somewhat common.

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