You know those little warts you have on hands and knees in childhood? They are a type of HPV. The human papillomavirus is a common skin virus, but only some strains or varieties are really dangerous.

Common warts often develop in childhood because there are breaks in the skin of active kids and the immature immune system can’t shrug off the virus. We used to squeeze sap from the milk thistle on them and I swear it made them go away. (We mostly grow out of these warts.)

Then there are plantar warts. Did any one else have them? I developed them on the soles of my feet, having caught them in ideal conditions – the changing rooms at the Tepid Baths. Talk about painful. They were awful until one doctor soaked my feet in a toxic chemical solution and they peeled away like magic.

There are about 150 varieties or strains of HPV. Genital warts for example are nastier again than the plantar and common wart and are are caused by strains 6 and 11 of the HPV virus.  Caught during sexual intercourse, they can take two years to go away with treatment. They are usually visible and knobbly like the common skin warts. Although they are genital, they have nothing to do with the strain or type of the virus that causes cervical or head and neck cancer. However, the Gardasil 9 vaccine that protects us from a number of HPV strains also protects us from these beggars. Incidences of genital warts are decreasing as more and more people have the HPV vaccines.

These HPV types, and more not mentioned here, do not lead to cancer. There are two strains that do, HPV 16 and HPV 18. 

These strains of the HPV virus are spread by sexual contact where the virus burrows into the cells in the cervix, the tonsils or the base of the tongue and sits there for years, maybe decades, slowly changing the DNA of the cells. (The penis, anus and other genital areas are also affected but not as frequently.)

Most of us are exposed to the more unpleasant types of HPV once we have been out in the world for a while. 80 to 90 % of us! We shake it off over a couple of years. But for the unfortunate few, the immune system does not destroy the virus and it remains to turn into a cancer in middle age or later.

Cervical cancers are usually HPV related but can be detected early in the precancerous stages by the Pap smear. The same cannot be said for the oropharyngeal or throat cancers which are usually not detected until they have spread to a lymph node in the neck or a visible lump can be seen or felt within the throat.

Most head and neck cancers are cancers of the squamous cells or flat cells that line our skin and mucosa. They are referred to as SCCs or squamous cell carcinomas. The mechanism for developing these cancers is via a carcinogen or unknown cause like tobacco, excess alcohol, chronic irritation, random genetic mutations or the HPV virus.

HPV-related head and neck cancers are SCCs just like their non-HPV cousins. If you have a cancer of the oral tongue (front part) it is likely to be negative for HPV. If you have a cancer of the base of the tongue, it is likely to be HPV-related. The virus likes tonsillar tissue like the tonsils themselves or tonsil-type tissue at the back/base of the tongue. They are “sticky” areas for the virus.

Good news is that the latest vaccine, Gardasil 9, protects against lots of these HPV strains, preventing cancers and genital warts. The vaccine gives us antibodies to the virus so we never get it but it can’t heal a person who already has the virus in their body. Most adults will have antibodies anyway if they’ve been exposed to the virus and the immune system got rid of it.

Having the vaccine after the age 26 is not likely to do much good. However, there is a bit of a grey area here and some practitioners who treat patients with the virus will vaccinate themselves because they are frequently exposed to virus particles. There’s some small evidence (tiny) that vaccination will boost the immune response to genital warts but this is all conjecture at the moment.

The best plan is to get children vaccinated before their sexually active years and while their bodies respond well to the vaccine. If you are too old to vaccinated, have the smear tests if you’re a woman and for all genders watch out for the warning signs of HPV throat cancer, a lump in the neck or unusual symptoms in mouth, throat, ears.