They are going to charge the US ~$40. So $800,000 to prevent 150 cases. That's incredibly cheap, and doesn't factor in an increase of social activities.

if it's targeted at the elderly/at risk (at first?), the reduction in hospitalisation should be higher; and I'd think that would pay back pretty quickly.

Yes, it's likely a net reduction in spending, and then on top of that a bunch of harm and death is prevented. Super cheap.

Already answered two days ago:

https://news.ycombinator.com/item?id=25111284

In short, we still don't know which measures would have to be kept even when a lot of people are vaccinated. It will be much better known in some time, but it's still not known at this moment. It depends on sterile immunizing properties of the vaccine, which are still unknown.

Edit: re the Moderna protocol mentioned in sanxiyn's comment below: even if they will measure sterilizing immunity (as one of their "Secondary" objectives), as far as I know, they still haven't published something on that topic (1) From them we still have only data on the level comparable to those from Pfizer/BioNTech:

90 cases in placebo, 5 in vaccinated, 11 severe cases, all in placebo group. Where "cases" could simply be defined "those who were recognized of having Covid-19" (as the illness). (Also see my other comment here for more general references about the primary objectives of all Phase 3 trials).

Here's what Moderna only writes about their secondary objectives in the only release: "Key secondary endpoints include prevention of severe COVID-19 disease and prevention of infection by SARS-CoV-2. The trial will continue to accrue additional data relevant to safety and efficacy even after an EUA is submitted." Meaning, eventually, we should be able to know more.

I didn't know that Pfizer doesn't even have that kind analysis written in their protocol, thanks. I'd hope they can add that in some later phase.

1) https://investors.modernatx.com/news-releases/news-release-d...

If I am reading Moderna's protocol right, it does evaluate sterilizing immunity. You are right Pfizer's protocol doesn't collect data to evaluate it.

https://www.modernatx.com/sites/default/files/mRNA-1273-P301...