The effect will necessarily appear weak when incidence of HPV is over 80%. At 95% it would appear weaker yet. That any signal shows up under the circumstances means the effect is huge.
With respect, this isn’t an accurate interpretation of an odds ratio. If you look at other cancers with a clear viral cause (EBV and nasopharyngeal carcinoma, HPV and cervical cancer), you will see that nearly 100% of tumours show evidence of viral infection and the odds ratios are very high, even though the viruses are ubiquitous.
The data for HPV and prostate cancer suggest, at best, an indirect effect such as inflammation rather than direct viral oncogenesis.
In any case, how do you modify this potential risk factor? Celibacy or vaccination. As I said, I would encourage any teenage male to get the HPV vaccine. It is worth paying for, if you can.
For cancer categories that are caused only by HPV, the signal would be clear even at 95%. But many categories have multiple possible causes. A cancer that could be caused by HPV or something else is still sufficient reason to get vaccinated.
Everybody not already exposed to HPV should get vaccinated against it. All insurance companies should be obliged to pay for such vaccinations.
