More vaccines seems like one of the most straightforward future mitigations since viruses like Hepatitis/HPV/mono/HIV/herpes/etc cause almost a fifth of cancer cases:
That is a dubious claim. While links between HPV and cervical cancer are quite strong and well-defined, the associations with the other viruses you cite are only correlative. Also, Hep C, HIV and herpes have no vaccine, so unclear what your statement is referring to anyway? What has contributed to a drop in cancer mortality would be advances in treatment (like targeted therapies and immunoncology), better image/blood/genetic screening practices, and certainly the decreased popularity of smoking.
This particular virus has a solid link to various forms of cancer:
"[Epstein–Barr virus] has also been implicated in several other diseases, including Burkitt's lymphoma, hemophagocytic lymphohistiocytosis, Hodgkin's lymphoma, stomach cancer, nasopharyngeal carcinoma, multiple sclerosis, and lymphomatoid granulomatosis.".
The word "implicated" in science normally means "correlated with" and can't really be considered a "solid link".
Some of the articles cited in that section have sentences like "1 out 2 (50%) adult analyzed cases was positive, with 50% of stained tumor cells (this patient was a 22 years old female, coming from Napoli);" that don't follow the necessary standard of evidence. I continued to skim the linked articles and they are all clearly correlative.
It's a lot more subtle than that. First off let me say that historically, demonstrating that a virus causes cancer has been a major bit of work, and many times people have mistakenly seen associations and falsely believed they were causal. second, I don't deny there are some cancers which are caused by viruses. But, you're referencing extremely rare cancers, not the cancers that make up the bulk of US (or world) deaths from cancer. My complaint is about taking these relatively rare situations and implying there's some sort of general underlying well-understood cause, when the reality is, in many situations, the virus itself did not specifically "cause" the cancer, but for complex biological reasons, it's "associated" with the cancer (which could manifest as increased susceptibility to getting particular types, or worse prognosis, or even possibly better outcome).
> While links between HPV and cervical cancer are quite strong and well-defined, the associations with the other viruses you cite are only correlative.
HPV is merely correlative, as well. That's basically how all endogenous cancers work. With Epstein-Barr Virus the association is quite strong, though the incidence of EBV-induced cancers doesn't seem to be quite as large as HPV--~1% vs 2-3%.
HPV isn't correlative, it's causative. Additional co-transformation factors may be required, but it is well understood that E6 and E7 proteins directly lead to tumorigenesis. EBV pathogenic mechanisms are more autocrine and therefore a muddier picture, hence correlative.
> Also, Hep C, HIV and herpes have no vaccine, so unclear what your statement is referring to anyway?
OP is talking about more vaccines as possible future mitigations - more vaccines as in new vaccines, not more vaccinations using existing ones (though that wouldn't hurt either.)
https://en.wikipedia.org/wiki/Oncovirus