I think you misread the story. It says

"we have come very close to the creation of so-called cancer vaccines and immunomodulatory drugs of a new generation. I hope that soon they will be effectively used as methods of individual therapy"

I think you misread it as "we will create comprehensive, all-purpose oncovaccines", when in fact it just says "we will create oncovaccines", which is pretty likely given that it's 2024 now. To use your analogy, it's like saying they're close to creating some vaccines for some respiratory viruses, which is plausible.

I don't get why you say, "any and all... all kinds of cancers developed in secret and finished and released at the exact same time." There is nothing like that in the story – besides which, it just doesn’t make sense for a real set of vaccines.

I also don't understand why you said they'd be "developed in secret", as there's no reason to think that and it doesn't make sense.