Human Papilloma Virus (HPV)

HPV is the most common sexually transmitted infection (STI) and prior to the national HPV vaccination program it was estimated that about 80% of the population would acquire at least one strain of HPV at some point in their lives. There are over 200 different strains of HPV some of which can cause cancer and some of which can cause genital warts. Of these many strains only about 40 of them are transmitted through sexual contact. For most people this STI will not cause any harm at all and the body usually clears HPV itself after 1 to 2 years. Even if you do come in to contact with a strain that causes cancer the chances of developing cancer are very small and it takes many years to actually happen.

How do you get HPV?

HPV is transmitted through skin to skin contact and is most commonly transmitted through vaginal sex, oral sex and/or anal sex. Most STIs can only be transmitted through some form of penetrative sex but HPV (and genital herpes) can be transmitted through skin to skin contact that doesn’t involve penetrative sex and so a condom won’t always protect you from acquiring it. Fingers and sex toys can pass on this STI so even women who have only ever slept with other women can acquire HPV. Once HPV has been acquired your body might clear the infection on its own or it may cause symptoms weeks, months or even years later. This means its usually not possible to identify when or how you acquired it.

How can HPV be prevented?

Condoms do provide some protection against HPV but it can still be transmitted even when condoms are used.

The most effective way to prevent against HPV is to be vaccinated before becoming sexually active. Their are 3 different types of HPV vaccine including Cervarix, Gardasil, and Gardasil-9. Cervarix prevents against strains 16 and 18 which together cause about 70% of all cervical cancer and 80% of all anal cancer. Gardasil protects against strains 6, 11, 16 and 18 (strains 6 and 11 are a cause of genital warts). Gardasil-9 protects against strains 6, 11, 16, 18, 31, 33, 45, 52 and 58. The extra strains in Gardasil-9 are a cause of the the remaining 20% of cervical cancer not caused by strains 16 and 18.

For those who are already sexually active getting vaccinated against HPV may still be a good idea. Even though it’s very likely those people will have acquired this infection already they may have subsequently cleared it naturally and they probably haven’t acquired all of the strains that can be a cause of cancer or genital warts. Furthermore, for younger people who are sexually active but who have only had sex with people who have been vaccinated it is very unlikely that they will have acquired those strains most likely to cause cancer and genital warts. This process is called herd immunity.

The decision to vaccinate an adult who is already sexually active depends on how likely they are to have already acquired multiple strains of HPV and their risk of acquiring this infection in the future. Men who have sex with men are less likely to benefit from herd immunity since and are at increased risk of cancers like anal cancer. This is a group that should consider getting vaccinated.

How is HPV diagnosed?

For the most part, HPV isn’t diagnosed because it is not useful to diagnose it. There is no available test to determine if you have this STI in the anus, mouth or throat. The only diagnostic test for detecting HPV before it causes symptoms is the cervical cancer screening test which is the test that has now replaced pap smears. It is collected in the same way as a pap smear but is technically a different test and it is only useful for preventing cervical cancer in women.

Should men be tested for HPV?

There is currently no good way to test for this STI in men and in particular there is no good way to test for anal cancer in men who have sex with men (MSM). Anal cancer is much more common in MSM and particularly so in MSM who also have HIV but in the general population this form of cancer is rare. There is interest in the idea of testing for HPV in MSM and in MSM who also have HIV but if it were to be detected its not clear whether or not it should then be treated or even how it would be treated.

In women with cancer-related changes of the cervix a procedure can be done to either remove or destroy the affected area. An equivalent procedure in men hasn’t been developed and would be technically difficult to perform because the part of the anus that can turn into cancer is much larger. Even if this could be easily done it still wouldn’t be clear when it should be done.
For MSM over the age of 35 and particularly for HIV positive men one option to detect anal cancer is to undergo a digital ano-rectal examination (DARE) once a year to feel for signs of an early anal cancer.

How is HPV treated?

There are no treatments that are performed only for HPV infection. There are vaccines to prevent infection and treatments for this STI-associated conditions like warts and cancer. Typically these treatments involve removal or destruction of the affected area be it a wart or a part of the body that is at risk of becoming cancerous.