So while on a personal level, there may not be dramatic differences in death rates etc., on a population level the differences are huge.
The reduction in transmission rate for the vaccinated is 89%. Even for someone with a breakthrough infection of the more contagious Delta variant being vaccinated means a 63% reduction.
https://www.newscientist.com/article/2294250-how-much-less-l...
First thing I noticed is these result actually select people who had the antiviral administered to them within 3 days of the symptoms appearing. I have personally known people who unfortunately died in a week tops after contracting the virus (they had pre-existing conditions, namely hypertension and diabetes).
Which brings me to my next point: Suppose the antiviral exists and is viable to even beyond 85%. How much will it cost ? I'm not a US citizen, but I'm thinking insurances will rush to trying not to cover anyone who's not vaccinated or some shady shit because they always do. And how about 3rd world countries like the one I come from. We can't even get RNA vaccines, let alone an experimental drug like this.
And now my final and target point: Suppose you don't want to get the vaccine and you can afford the drug. We do have proof that even if the vaccine doesn't protect you from the virus completely, even in the unfortunate case where you do contract it, you'll end up infecting less people. Now if you choose to not get vaccinated, then you really do risk potentially contaminating more people that will either have no access to the antiviral within a reasonable effective timeframe(and that maybe not vaccinated either) or just plain infecting more people overall.
Not the cleanest reasoning, and not a mathematical proof by any means, but I believe it's one of those "mathematical" problems where the proof is finding an edge case (sorry studied in french, really don't know how they say it in english).
What is a "rational society" and what threatens it?
My default view is Rawlsian: I'd like to live in a society which maximizes the well-being of the least well-off people, even if that's not currently me. In that framework one threat from a pandemic is that some at-risk people might die (people with some health conditions will die when infected and may not respond well to vaccination); that threat can be mitigated if people develop treatments, apply nonpharmaceutical interventions like indoor masking, and participate in community inoculation.
There are other very different notions of a "rational society". In some, the premature death of people who are elderly, medically at-risk, or choose to avoid vaccination might be preferred outcomes. Hmmm.
Also, the vaccines work on a principle that's somewhat well understood, accepted and deemed safe: training the immune system by giving it something that looks like the virus so it can learn. The only novel part is how this "something that looks like the virus" is created (mRNA as opposed to weakened but real virus). On the other hand this new molecule has a totally different mechanism of action and the potential for side effects may be higher.