HPV vaccine: Preventing a sexually transmitted cancer
September 19, 2019
Let’s talk about the most common
yet least discussed sexually transmitted infection, human papilloma virus (HPV),
and the important change in vaccination guidelines.
More than 95% of sexually active adults will be infected with HPV at some point in their lives and never know it. The Centers for Disease Control and Prevention estimates there are approximately 79 million people infected with HPV at any given time and 14 million new HPV infections in the U.S. each year.
The highest rates of HPV infection are among women aged 20-24, and higher rates are seen in the southern region of the U.S. In addition, HPV is linked to 34,800 cases of cancer in America every year – of those, 20,700 are women and 14,100 are men, according to the CDC.
In August 2019, the CDC updated its HPV immunization recommendations and raised the age for the "catch-up" vaccine to 26. And in specific cases, vaccination up to age 45 could provide benefits.
You might ask why this matters to you. The answer can be found by examining the characteristics and transmission methods of HPV:
I have never had sexual intercourse. Could I have HPV?
Yes. If you have had any intimate skin-to-skin contact, you are at risk of HPV transmission.
I use a condom; won’t that protect me?
No. Condoms only cover a limited area of skin in one specific region of the body. HPV can be spread through any intimate skin-to-skin contact. Visible lesions do not need to be present to transmit HPV.
Approximately 90% of infections will be silent and most are cleared by your immune system. Like other viruses, HPV can lay dormant for decades before reappearing. When your body’s immune system does not clear HPV, it becomes a persistent infection that can lead to cancer. There are more than 200 types of HPV, and of those more than 40 types infect the genital tract of humans.
What are the symptoms of HPV and how do I know if I have HPV?
Most HPV infections are asymptomatic or subclinical and are never diagnosed until more overt signs appear such as genital warts, an abnormal pap smear, or cancerous lesions.
Does the number of sexual encounters matter?
Yes. One intimate skin-to-skin contact can transmit HPV and cause infection, but a greater number of sexual partners is associated with a higher likelihood of acquiring a type of HPV.
Of the 40 types of genital HPVs, there are two groups we are most concerned about. Low risk HPVs are considered non-cancerous and usually cause genital warts and low-grade cervical cellular changes. High-risk types are oncogenic, which can cause tumors and cancer.
Which types of HPV should I be worried about?
The high-risk types are associated with cancers of the vulva, vagina, anus, penis, rectum and throat (including the tongue and tonsils).
Per the National Cancer Institute:
- Virtually all cervical cancers are caused by HPV. Routine screenings can detect cervical cell changes.
- Most oral cancers are also caused by HPV, and oral cancer is now the most common HPV related cancer in the U.S.
- The majority of rectal cancers are due to HPV and the rate of rectal cancer has increased steadily since 1992.
- 60% of penile cancers are HPV.
- 75% of vaginal cancer and 70% of vulva cancer are attributed to HPV.
Is there a treatment for HPV?
No. There is not a medication that treats HPV. However, some HPV-associated manifestations, such as warts and cervical cell changes, can be treated with localized medication and/or surgical procedures.
The best way to reduce the transmission of HPV and protect against its associated cancers is with a vaccine. Since 2006, routine HPV vaccination in females and males up to age 26 has been recommended.
New clinical trial data has shown that women who received the HPV vaccine after age 27 had a reduction in the prevalence of persistent HPV infection, genital warts and cancer. Given this new finding, the FDA has recommended increasing the age limit to 45 for both women and men.
This is significant since more than 80% of women will have been infected with genital HPV by the time they reach age 50.
Which HPV vaccine is available in the U.S.?
Commonly known as Gardisil-9, it targets seven different oncogenic HPV types (16, 18, 31, 33, 45, 52, 58), which account for 80% of all cervical cancer. It also takes aim at HPV types 6 and 11, which cause about 90% of all genital warts.
How effective is the Gardisil-9 vaccine?
In countries where female vaccination coverage is at least 50%, studies have shown HPV types 16 and 18 decreased 68%and anogenital warts decreased 61% in girls age 13-19. In the U.S., eight years after introduction of the HPV vaccine in 2006, prevalence of HPV decreased 71% among 14- to 19-year-olds and 61% among 20- to 24-year-olds.
Much of the focus seems to be on preventing cervical cancer in women. Why should males get the vaccine?
To help prevent HPV transmission to women, and to help prevent HPV-related cancers that occur in men. There are an estimated 13,500 cases of HPV oropharynx (throat and mouth) cancer each year, according to the CDC. Of these, 11,300 occur in men.