How they lost their fertility...

There was a SARS type of virus that infected a majority of global population rendering men and women infertile. No vaccine or treatment was available to reverse infertility and as the movie shows us there is very little hope from the scientific community that there will be a cure. Being a fictional story it didn't need a "virus is a hoax" narrative unlike what we are seeing in the very real pandemic now.

you sound like a tin foil had nut.job