The vaccine was mandatory, like in pretty much every army base of every half developed country, because not having it mandatory led to infection waves and in the army that's even worse than in genpop.

The reasons for not doing the vaccine anymore were, essentially, "the vaccine is more dangerous than the sickness" and "the vaccine is not necessary to avoid the sickness".

Both of those statement are, factually, scientifically, not true. That's reality. Which is what parent meant, no matter the deep conviction and the political innuendo, ultimately reality is you either do the vaccine and are safe for no risk or you don't and you get infection waves.