This month we start looking at specific STD’s and we are starting with HPV.
HPV is the human papilloma virus, and it is extremely common. There are over 200 different strains, most of which are pretty harmless, and probably not a human on the planet that has not been infected. They are spread by skin to skin or epithelium to epithelium contact. As verrucae are said to be spread from swimming pools then I guess some strains can be spread by contact with recently contacted surfaces too. Some strains cause warts; some cause cancer of the cervix. HPV can also cause cancer of the penis, anus, and cancers of the head and neck, but they are very rare. Those that affect mucous membranes can be divided into high risk and low risk types. Persistent infection with high risk strains can cause cervical cancer, whereas low risk types can cause genital warts. The 8 most common of the high risk strains are responsible for 90% of cervical cancer, but just 2, type 16 and 18 account for 70%. Types 6 and 11 are responsible for 90% of genital warts.

Testing for HPV is difficult; it is a research tool and is not done routinely as a screening. Because it is the cause of a cervical cancer what we test for is the evidence of persistent infection of the cervix.

HPV is spread by contact between infected skin and mucous membranes. It is not only spread by full penetrative sex, hence the big publicity drive to encourage early vaccination from age 11. Not all infection leads to cancer: in fact in the UK less then 1% of women infected with HPV will get cancer, in most cases the virus goes away on it’s own and early screening treats it before it becomes cancer. The number and frequency of infections and early age of infection increases risk. Condoms may reduce the risk of transmission but good research has shown little if any difference in prevalence between those that use condoms and those that don’t. This comes as no surprise to me at all: a condom reduces the risk of other diseases by 10 times. But that only means that 10 times with a condom equals once without. So lets play Russian roulette, but with the added interest that you can choose one of 10 pistols to play with!

To make it even more interesting, it is undetectable in men, no one is screening men, and only the unfortunate few with a nice visible crop of warts growing off their glans are aware of infection with HPV at all. Better just to assume that any man who has had sex with anyone else has a high risk of HPV: he may give you warts, or if you are unlucky persistent infection with one or more of the strains causing cancer.

So what is the risk in Uganda?

Extremely high. Very few women indeed go for PAP smear screening to detect early HPV neoplastic changes, and full on cancer of the cervix is a common and truly horrible cause of death. We see plenty of young girls especially visitors with visible warts, a reminder that the virus is out there and being regularly transmitted despite the “protection” of a condom. For every visible wart on the outside there are others with invisible warts further in, plenty of others with asymptomatic infections, and plenty more with the invisible strains that can cause cancer.

So what to do?
The only way to really reduce the risk is reduce the number of partners. The best is one for life, like the Great Auk, some duikers, jackals and Dr Stockley. This makes your risk of HPV and any other STD as close to zero as possible. Every time you have a new partner, or sex with someone who is having new partners and therefore new infections, you increase your risk of a persistent infection with one of the high risk strains.
Choose the right man.  Plenty of men still believe it is right and normal to have multiple partners, and their only responsibility is make at least some effort to make sure the regular girl doesn’t find out about the others. Unfortunately history, literature and everyday experience teaches us that girls still fall for the worst possible men!
Age of debut. Postponing first sex as long as possible reduces risk as teenage infection has a greater risk of cancer.
Vaccination. The new vaccine is expected to reduce the number of cases of cancer by two thirds. There are 2 types. Cervarix is available in Uganda and immunizes you against type 16 and 18. Gardasil can be ordered from London and also includes types 6 and 11. Both require 3 doses and are pretty expensive, around 250,000/= a shot for cervarix and about 3 times that for gardasil at present. Both reduce the risk of cancer by about 70% and gardasil also reduces the risk of visible genital warts. Both are licensed for use in women age 9 to 25. Vaccination is most effective if given early: the antibody response is greater when given to younger girls, and also there is some risk from early non sexual contact. The UK recommends routine vaccination to all girls at age 12, but a catch up period of a year giving it to everyone up to age 18. It can be given to anyone, but is obviously most effective if given before having sex. We recommend it to every teenager regardless of past or present risk, as you may be lucky and not yet have the 2 strains that are in the vaccine.
Pap smear screening. This is still the mainstay of cervical cancer risk reduction. Different countries have different protocols but one sensible regime is all women who have been sexually active should have regular pap smears every 3 years, and every year if you have had a past abnormal smear or another partner. I am way out on a limb with this one, but I see little point in having any more smears after 6 or 9 years if you have one partner for life: where are you going to get an abnormal smear from? I don’t expect many people to agree, but I would like to those who do not to answer the question!
A pap smear is easy, cheap and a very effective way of detecting early damage to cells from persistent infection, and can be done by a trained nurse. However be warned! A poorly taken sample is a waste of time and money! With the old system I am used to the sample is “scored” by an E number: E3 means lots of the endocervical cells which can be affected by the neoplastic changes, down to E2 and 1 which are adequate, and E0 which means no cells, and is therefore a substandard sample which needs repeating. This is then followed by a description of the cells, negative, or CIN 1, 2 or 3, or fancy words like mild dysplasia. The doctor or nurse taking the sample should explain what they mean, but basically what you want is an “E3 negative”. There are many other ways of reporting, some more maradadi than others. If you are worried that you don’t understand the report, especially the sample quality, then ask, as inadequate samples should be repeated, free of charge!
Summary
HPV is extremely common
A few people infected with HPV are at risk of cervical cancer or genital warts
Condoms do not appear to reduce the risk
The new vaccines prevent the commonest strains causing cancer.
All sexually active women need regular good quality pap smears.