Science of Sex: HPV and the HPV Vaccines

June 17th, 2017

Welcome to the fourth installment in a new feature on Of Sex and Love: Science of Sex. In this feature, I plan to discuss the science of sexuality in an easy-to-digest format that’s accessible to the casual reader. I will also follow up with some extended reading material for people who want to know more about the subject of each post.

Enjoy!

Science of Sex HPV

Human Papilloma Virus in a Nutshell

HPV is the virus that causes genital warts, but just because you don’t have any symptoms doesn’t mean you don’t have HPV. It’s one of the most common sexually-transmitted infections with over 200 strains (strains 16 and 18 cause over two-thirds of all cervical cancer while low-risk strains 6 and 11 cause most warts). Over 80 million people or about 1 in 4 people have it. It’s easy to transmit through skin-to-skin contact, so even using condoms may not prevent HPV. The CDC advises that ‘nearly all’ men and women will contract HPV in your life, and it’s likely that many people don’t even know they have it.

HPV doesn’t just cause warts. It can lead to irregular PAP smear results for women and cause cervical cancer (HPV can also be the culprit for other cancers, including that of the throat and anus). Those results can lead to a woman getting tested for HPV, but there is currently no test for HPV in men who have an asymptomatic strain (some sources indicate that a test does exist but it’s expensive and invasive).

Treatment of HPV may mean doing nothing at all. Most cases clear up within two years, but this isn’t always the case.

The HPV Vaccine

A vaccine for several of the most common strains of HPV, including some that cause cervical cancer, Gardasil, became available about 10 years ago. There are now three different vaccines for HPV available (Cervarix, quadrivalent Gardasil, and 9-valent Gardasil-9), the latter of which cover more strains of HPV than the original. One study concludes that HPV vaccines can prevent “most” invasive cervical cancers (around 70% of cervical cancer for the 9-valent vaccine and 66% for original Gardasil) as well as some oral cavity, penile, laryngeal and vulvar cancers. These vaccines are at least 90% effective at blocking those strains.

The vaccines consist of three doses that you can take between ages of  11 and 27 (for women) or 21 (for men). Younger patients may only need two doses. Even if you can’t take all shots within this time frame, you’ll still benefit from at least one dose. Similarly, the vaccine is still beneficial if you’ve already become sexually active, but it’s more beneficial if administered before sexual activity. In this case, the younger the better.

Although at first recommended for girls, HPV vaccines are beneficial for boys who can contract and transmit HPV. But it’s less likely that a male will no if he’s HPV-positive, which means he’s more likely to transmit it to a partner.

Still, fewer boys than girls are being vaccinated (12% of boys had received all three doses compared to 36% of girls in 2013), and vaccination occurs at a later age. Fortunately, vaccination rates have increased through the years, perhaps as no serious side effects have arisen over the years and the efficacy of the vaccines have been proven. For girls, infections by strains of HPV that the vaccine prevents has dropped 64% since 2006.

Let’s hope that vaccination rates rise, gaps close and strides can be made to cover more strains of HPV in future vaccines!

Further Reading

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