HPV vaccine: Why is it important?

Human papilloma virus (HPV) is the most common sexually transmitted pathogen in the United States. About 79 million people in the U.S. are currently infected with it, according to the Centers for Disease Control and Prevention. In susceptible individuals, the initial infection produces a wart-like rash in the genital area ("venereal warts") although many infections occur without symptoms. Many HPV infections go away, but sometimes HPV infection can cause cancer.

In fact, HPV is the leading cause of cervical cancer and cancer of the mouth and throat in the U.S. About 17,600 women get cancer that is linked with HPV each year with cervical cancer being the most common. Around 9,300 men each year get cancer caused by HPV infection, and the most common are cancers of the back of throat, tongue, and tonsils, according to the CDC. The virus can also cause a severe throat infection (laryngeal papillomatosis) in newborn infants.

When should my child receive the HPV vaccine?

Data suggests that most sexually active Americans have evidence of infection.  As a result, effective vaccination should be complete before the onset of sexual activity.

While children as young as 9 may be vaccinated, the CDC and the American Academy of Pediatrics recommend initiating a three shot HPV vaccine series between 11 and 12 years of age for both boys and girls; the second shot is given at least 1-2 months after the first one and the third is administered at least 6 months after the FIRST dose.

Vaccination is also recommended for unvaccinated or incompletely vaccinated females 13-26 years of age and males aged 13-21 years of age.  Immunosuppressed subjects and gay men may be vaccinated up to 26 years of age.  Younger children not only respond better to vaccination, but are much more likely to be uninfected.

Why is the vaccination level for the HPV vaccine low compared to other vaccines?

The number of 13 to 17-year-old boys and girls getting the HPV vaccine increased slightly for the second year in a row, according to data from CDC's 2014 National Immunization Survey-Teen. Despite these increases, four out of 10 adolescent girls and six out of 10 adolescent boys have not started the recommended HPV vaccine series, leaving them vulnerable to cancers caused by HPV infections.

These rates are low, in part because of concerns that HPV vaccination may promote unsafe sexual activity by lowering perceived risks of acquiring a sexually transmitted infection. A recent study in JAMA Pediatrics found that the rate of STIs overall were equal among the vaccinated and unvaccinated groups of US girls. The researchers concluded that this meant the vaccine itself does not change sexual activity or behavior.

What types of HPV vaccines are available now?

There are over 100 different strains of HPV of which 30 cause disease.  The original HPV vaccine that was tested provided coverage against the two strains most often implicated in cervical cancer, types 16 and 18. In the original studies, almost all of the vaccines had protective antibody after completion of the basic three shot series. Clinical studies with a vaccine directed against four strains of HPV have demonstrated protection against cervical and oral cancer as well as venereal warts.

This spring, the CDC recommended adding the 9-valent HPV vaccine to the armamentarium for HPV prevention.  At the present time, the 2-valent, 4-valent and 9-valent vaccine are all acceptable for immunizing adolescent females and young women; males should receive the 4- or 9-valent vaccine.

Any new information on the 9-valent HPV vaccine?

Earlier this summer, this CDC released additional guidance for healthcare providers who may have questions about using the 9-valent HPV vaccine in patients who've already received the bivalent or quadrivalent version.

The 9-valent vaccine may be used to complete a series that began with the older versions at the same dosing schedule (doses given at 0, 1–2, and 6 months).

If your child is fully vaccinated with the 4-valent vaccine, do you need protection against the five additional strains in the 9-valent version? Your provider may point out that the older vaccine protects against the majority of cervical cancers (those caused by types 16 and 18), and the benefits of the new vaccine are largely limited to females. Data show no serious safety concerns in people who've received the 9-valent vaccine after a full series of the older vaccines.

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