UAB Medicine

January 14, 2013

How late is too late for the HPV vaccine?

Question: My friend told me that you can’t get the new HPV vaccine if you’ve ever had sex. Is this true?

Answer: No. This is a common misconception because experts have recommended the vaccine for girls and boys aged 11 to 12 years in an effort to protect them from human papillomavirus (HPV) infection before they become sexually active. Gardasil is the only FDA-approved HPV vaccine for girls and women aged 9 to 26 years. The current American Cancer Society recommendations are for the initial vaccination to start with girls aged 11 to 12 years, with catch-up vaccinations for girls aged 13 to 18 years who are not yet vaccinated. Sexually active women, aged 26 and younger, can still receive the vaccine, but it may not be as effective if they are already infected with HPV.

HPVs are a group of more than 100 viruses; 30 of these are transmitted through sexual contact. Different types of HPV can cause warts, or papillomas, on different areas of the body including the hands, feet, genitals, and throat. Some HPVs are classified as low risk because they cause only minor problems such as noncancerous Pap test abnormalities or genital warts. Persistent high-risk HPV infections are the types linked to an increased chance of cervical precancer (abnormal growth or development of cells) and cervical cancer.

Gardasil is the first vaccine marketed specifically to prevent HPV infection and the development of cervical precancer and genital warts. It protects against four types of HPV: two types that cause 70% of cervical cancer and the two additional types that cause 90% of genital warts. While the FDA has approved Gardasil for girls and women aged 9 to 26 years, Cervarix, an FDA-approved HPV vaccine, is intended for girls and women aged 10 to 45 years. Cervarix is also highly effective in preventing HPV infection and cervical precancer.

To get full protection from the HPV vaccine women need three injections during a 6-month period: the first dose at the first visit to the doctor, another dose 2 months later, and a third dose 6 months after the first. Experts don’t yet know how much protection one or two doses provide, so it is important to complete the entire schedule.

You can’t get HPV from the vaccine, and experts reported no serious adverse effects during the vaccine tests in more than 21,000 women worldwide. Pain at the injection site is the most common complaint, but it doesn’t last long.

People who are sexually active and who may have acquired one or more types of HPV covered in the vaccine can still benefit from vaccination, but they may get less protection than those who have never been exposed to HPV. However, it is rare for young women to be infected with all four of the HPV strains in the vaccine. Thus, it provides protection from types not yet acquired. HPV screening prior to vaccination is unnecessary and not recommended.

HPV is the most common sexually transmitted disease in the United States. The Centers for Disease Control and Prevention (CDC) estimate that about 6.2 million Americans are newly infected with genital HPV each year and more than half of all sexually active men and women become infected at some point during their lifetime. By age 50, at least 80% of women will have acquired an HPV infection, the CDC reports.

Most HPV infections don’t cause any symptoms and resolve on their own. Although there is no cure for HPV, doctors can treat many of the conditions it causes, such as genital warts and cervical precancer.

Some HPV strains can infect the cervix (the lower part of the womb) and cause changes in cervical cells. If the body’s immune system clears the HPV infection, cells return to normal, but sometimes HPV infection persists. If infection lingers and isn’t treated, precancerous changes that can lead to cervical cancer may occur.

Although only a small proportion of women have lingering infection, persistent infection with high-risk HPV is linked virtually all cases of cervical cancer. Cervical cancer is the second most common cause of cancer deaths in women worldwide. The American Cancer Society estimates that 9700 women contract cervical cancer and 3700 die from it each year in the United States. In the developing world, where routine Pap tests are less available than in the United States, cervical cancer affects 470,000 women and kills 233,000 annually.

The vaccine could prevent at least 70% of cervical cancers in women who have not already been infected with high-risk HPV strains. Studies have shown that it is almost 100% effective in preventing infection from the four types of HPV in the vaccine for at least 5 years. However, it is still important to get Pap tests, which can detect precancerous cervical changes caused by HPV strains not in the vaccine. Women should undergo cervical cancer screening at 21 years or ago but not any earlier.

At $120 a dose, a complete HPV vaccination can cost as much as $500, making it one of the most expensive vaccines. Most major insurance plans cover the vaccine. Before deciding to get the vaccine, call your health insurance company to discuss your individual coverage. Insurance companies will not currently cover any costs for women older than 26 years because the FDA has not approved Gardasil for that age group. Federal health programs such as Vaccines for Children may cover the HPV vaccine for girls younger than 19 years if they are uninsured or eligible for Medicaid.