I believe more states would mandate HPV, but by definition it is not considered a communicable disease, and several states use a justification for K-12 student vaccinations that the disease be communicable in nature.
“I believe more states would mandate HPV”
First, none of them actually “mandate” any vaccine, because there are religious, philosophical, conscience or medical exemptions to all of them available in most states. I have conscience exemptions for my children, so they were not “mandated” to take anything during the few years they were in public schools. A home schooled child is more likely to be fully unvaccinated. Private schools are a mixed bag.