All I know is that back when I worked at Roche Labs, now known as Lab Corpe, they felt that we all should be educated on different forms of STD's. Human papillomavirus at that time was an STD. Small flat warts on a male's privates. Easily removed. Didn't affect the male in any way but passed on to the female caused cervical cancer.
Without looking it up, it’s 4 strains; 16 & 18 and 2 others with lower numbers. The ones that cause warts are different strains than the ones that could cause cervical cancer.......