That wouldn't be hard to believe IF you understood the science associated with viruses (especially) and vaccines,
"Thus, we cannot reject the assumption that the effect of the filtered lymph is not due to toxicity, but rather to the ability of the agent to replicate." F. Loeffler 1898 Principles of Virology 4th edition Flint, Skalka et al. 2015.
Yeah champ, IF people actually knew the history of virology, & had the basic intelligence to revisit or at least question the basic ASSUMPTIONS underpinning the field, then we would probably be, as a society, in a far better place.
That wouldn't be hard to believe IF you understood the science associated with viruses (especially) and vaccines, and bothered to do some basic reading about how human bodies fight pathogens - and sometimes itself. While you were gazing longingly into your mirror or possibly re-arranging your navel fluff collection medicine has been developing wonderful new things like anti-virals and targeted seasonal flu shots, for example.
As a general observation, every human on earth can benefit from ongiong upgrades, and most do. Those upgrades can come in many forms - sustenance, exercise, relaxation, opening your mind, learning to get perspective and at least a semblance of balance. As the saying goes, with knowledge and experience comes wisdom. Obviously that wisdom varies hugely, as even a cursory perusal of comments here show only too well.