HPV shot drops rates of infection in U.S. girls
A new study looking at the prevalence of human papillomavirus (HPV) infections in girls and women before and after the U.S. introduction of the HPV vaccine shows a significant reduction in vaccine-type HPV in U.S. teens.1 Since the vaccine was introduced in 2006, vaccine-type HPV prevalence has decreased 56% among female teens ages 14-19, data indicate.
"This report shows that HPV vaccine works well, and the report should be a wake-up call to our nation to protect the next generation by increasing HPV vaccination rates," said Tom Frieden, MD, MPH, director of the Centers for Disease Control and Prevention (CDC), in a release accompanying the report. "Unfortunately, only one-third of girls aged 13-17 have been fully vaccinated with HPV vaccine."
About 79 million Americans, most in their late teens and early 20s, are infected with HPV, the CDC estimates. Each year, about 14 million people become newly infected. About 19,000 cancers caused by HPV occur each year in U.S. women, with cervical cancer as the most common form. Some 8,000 cancers caused by HPV occur each year in U.S. men; oropharyngeal cancers represent the leading form.2
Researchers at the CDC used the National Health and Nutrition Examination Survey data to determine the proportion of girls and women ages 14-59 with certain types of HPV prior to the start of the HPV vaccination program (2003-2006), comparing those numbers to those gathered after vaccine introduction (2007-2010).
Among females ages 14-19 years, the vaccine-type HPV prevalence (HPV-6, -11, -16, or -18) decreased from 11.5% (95% confidence interval [CI], 9.2-14.4) in 2003-2006 to 5.1% (95% CI, 3.8-6.6) in 2007-2010, a decline of 56% (95% CI, 38-69), researchers report. Among other age groups, the prevalence did not differ significantly between the time periods (P greater than .05). The vaccine effectiveness of at least one dose was 82% (95% CI, 53-93), the analysis indicates.1
Lauri Markowitz, MD, team leader of the Epidemiology and Statistics Branch in the CDC’s Division of STD Prevention’s National Center for HIV, Viral Hepatitis, STD, and TB Prevention and lead researcher of the current report, said, "The decline in vaccine type prevalence is higher than expected and could be due to factors such as to herd immunity, high effectiveness with less than a complete three-dose series, and/or changes in sexual behavior we could not measure. This decline is encouraging, given the substantial health and economic burden of HPV-associated disease."
How to boost numbers?
While the current report offers promising news on use of the HPV vaccine, public health experts and clinicians are looking to have more people vaccinated.
While routine vaccination is recommended at age 11-12 for boys and girls, recent national immunization surveys indicate only about half of all U.S. girls and far fewer boys have received the first dose of HPV vaccine. HPV vaccination is also recommended for older teens and young adults who were not vaccinated when younger. (To read more on the subject, see the Contraceptive Technology Update articles, "Time to boost numbers for HPV vaccination," May 2013, p. 56, and "Improve rates now to finish HPV vaccination," STI Quarterly supplement, July 2012, p. 3.)
Healthcare professionals should make strong recommendations for HPV vaccination and vaccinate every boy and girl in their practice when the patients are 11 or 12 years old, says Markowitz. Missed opportunities data show that if HPV vaccine was given every time a clinician gave a tetanus, diphtheria, and pertussis vaccine (Tdap) or meningococcal conjugate vaccine (MCV4) dose, HPV vaccine coverage would be more than 80%,3 says Markowitz.
How can clinicians encourage parents to have their children vaccinated? Visit the CDC website at http://1.usa.gov/127fJjb for a freely downloadable fact sheet with tips and timesavers for talking with parents about thump vaccine, says Markowitz.
How about the influence of the HPV vaccine in U.S. males? Look for the first data on male prevalence to be available in 2014 from the National Health and Nutrition Examination Survey, says Markowitz.
Gardasil (Merck & Co., Whitehouse Station, NJ), the HPV quadrivalent vaccine, was licensed for males in the United States in 2009. The Advisory Committee on Immunization Practices did not issue a routine recommendation for quadrivalent vaccine use for males age 11 or 12, and through age 21 for those who were not vaccinated previously, until October 2011, notes Markowitz.
- Markowitz LE, Hariri S, Lin C, et al. Reduction in human papillomavirus (HPV) prevalence among young women following HPV vaccine introduction in the United States, National Health and Nutrition Examination Surveys, 2003-2010. J Infect Dis 2013; doi: 10.1093/infdis/jit192.
- Centers for Disease Control and Prevention. STD Facts: Genital HPV infection. Fact sheet. Accessed at http://1.usa.gov/14SwOvR.
- Centers for Disease Control and Prevention (CDC). National and state vaccination coverage among adolescents aged 13-17 years — United States, 2011. MMWR 2012; 61(34):671-677.