There was a Sci-Fi movie I watched last year, can't recall its title, but the idea was there are two very powerful hidden extraterrestrial forces who have opposite goals - one of them to increase Earth's population, so it harvests human energy or souls, or something like that and the other force trying to prevent that based on the negative outcome of previously harvested planets.
I believe real world case isn't far away from that, just that those forces aren't extraterrestrial...

Generally I think vaccines have saved millions of lives but they don't always work as we are all unique creatures. Until the time comes when everyone is genetically tested and then a personalized vaccine is created and applied, there will always be risks.

However, I am afraid we are not getting close to this point as in our present world, profits are more important than human lives... :(

I hope it all goes well with you!