It's difficult to achieve 90% vaccination rate because our societies are male dominated. I am a bit more optimistic about feminization of all males. Women are now surpassing males in academics and are gaining more and more power. It is only a matter of time when women will have taken over power and make the rules.
And not to forget males are easy to manipulate. Sissification has become such a powerful tool already that women can feminize males whether they want it or not. The knowledge is out there on the internet and it stays there. And there are more and more women sharing this knowledge with other women. Given how easy it is for an empowered woman to emasculate a male today I am optimistic that we will see feminization of all males in our lifetime.
It's not just males that are easily manipulated, people in general believe too much that's on social media, too easily.
The issue on Vaccination, comes from an English Doctor, Andrew Jeremy Wakefield who said Vaccinations cause Autism, even though his findings were discredited, and he was struck off English Medical Register, he later committed Suicide, Social Media started this anti-Vaccination crusade that people take as gospel, even if no one has verified this information.
Feminization or Sissification will not happen in one generation, it will have to be slowly approached and done under the radar.
check out "2088, it's a Sissy World" by RH Music on fictionmania is a sci-fi sissification story.