Most HPV infections clear alone; a few drive five percent of cancers
Human papillomavirus is a DNA virus family with more than two hundred types. About ninety percent of infections vanish within two years without symptoms, yet high-risk strains cause roughly five percent of cancers worldwide and about 37,300 U.S. cancer cases yearly.
HPV is the most widespread sexually transmitted infection on the planet, and almost everyone who is sexually active catches it at some stage. Over forty of its numbered types can pass between people through genital or anal contact, usually skin to skin. It infects only humans, a person can carry several types at once, and it can pass from mother to baby during pregnancy. Ordinary hand sanitisers and disinfectants do not kill it, which is why some researchers think contaminated surfaces could in theory carry it, although evidence for that route is limited. Starting sex young, having many partners, smoking and weak immunity all raise the chance that an infection lingers.
Persistence is the problem. A lingering infection can produce warts or precancerous changes, and roughly a dozen high-risk types, among them 16, 18, 31 and 45, are tied to cancers of the cervix, vulva, vagina, penis, anus, larynx and oropharynx. Nearly all cervical cancer traces back to HPV, with types 16 and 18 behind about 70 percent of cases; type 16 alone accounts for close to 90 percent of HPV-linked mouth, throat and tonsil cancers. Estimates for 2020 put cervical cancer at about 604,000 fresh diagnoses and 342,000 lives lost, around nine in ten of them in low and middle income countries.
Other types are far gentler. Types 6 and 11 cause genital warts and laryngeal papillomatosis, types 1 and 2 cause ordinary warts, and type 5 can sit in the body for life without any sign at all. Skin warts come from fast cell growth in the outer skin, are most common in children and often fade on their own within weeks or months, though they tend to return. Plantar warts grow inward on the soles and hurt when walking.
Warts were described in ancient Greece, but their viral origin was only shown in 1907, when Giuseppe Ciuffo injected wart extract into skin. Today vaccines protect against the commonest types, and direct HPV testing lets doctors catch changes early, when treatment works better.
Source: Human papillomavirus infection
