HPV vaccine update: Will older women be next?
Use of the cervical cancer vaccine may soon expand: Merck has filed with the Food and Drug Administration (FDA) for use of Gardasil (Merck & Co.; Whitehouse Station, NJ) in use in women ages 27 through 45.
Gardasil is currently approved for women ages 9-26. The Centers for Disease Control and Prevention (CDC) recommends the vaccine for all girls ages 11-12, with "catch-up" doses for those ages 13-26 who missed earlier vaccination.
The CDC's Advisory Committee on Immunization Practices (ACIP) is scheduled to offer its decision this month on whether to recommend the vaccine for the 27-45 age group. The panel's guidelines are widely accepted in setting vaccination schedules.
ACIP board members heard presentations on clinical trial and cost-effectiveness data regarding such use of the quadrivalent human papillomavirus (HPV) vaccine at its February 2008 meeting. According to information presented at the ACIP meeting, the panel could issue one of the four following options for use of the vaccine in older women:
- Not recommended.
- Permissive recommendation. This approach could benefit some women, but would end up excluding others if insurers don't cover the cost of the vaccine.
- Targeted catch-up recommendation, which would be risk-based. This approach may be problematic, since there are no clinically available tests to identify who has been infected or is immune to a specific HPV type.
- Extend the catch-up recommendation to all or part of this age group. This option could allow easier access to vaccine than the permissive recommendation; however, it could discourage Pap testing.1
Why older women?
Women remain at risk for newly acquired HPV infections and developing HPV-related diseases throughout their lifetime, says Jennifer Allen, Merck spokeswoman. The company submitted its supplemental application for expanding use of the vaccine in older women to the FDA in March 2008.
According to data presented at the ACIP February 2008 meeting, among women in their mid-20s, with increasing age, HPV prevalence decreases, HPV incidence decreases, but the likelihood of having acquired HPV infection increases.2
Where does the HPV vaccine fit in your current practice? If current numbers are any indication, vaccine use may be low: Only two out of every 10 women in the approved age group have gotten the vaccine so far.3
When it comes to women ages 19-26, there may be some confusion about vaccine use. While ACIP recommends universal vaccination for all women ages 11 to 26, regardless of sexual experience, the American Cancer Society (ACS) advocates vaccinating all females younger than 18 and selectively vaccinating women ages 19-26 based on informed discussion between the patient and her provider about sexual history.4 According to the ACS, a woman in the 19-26 age group who has been sexually active "may choose whether to receive the vaccine based upon her personal sexual history; an understanding of the likely diminished benefit with increasing likelihood of previous HPV exposure; and her values, preferences, and competing health care needs."4
A new study from the Child Health Evaluation and Research (CHEAR) Unit at the C.S. Mott Children's Hospital, University of Michigan Health System, finds that using certain risk factors, including sexual history, to determine if a woman should be vaccinated could deprive more than 80% of eligible women from getting the vaccine.5
Selectively vaccinating women based on risk factors alone would mean that more than 2 million women, ages 18 to 26, who have the potential to derive the most benefit from HPV vaccination because they weren't already infected, would miss out on getting the vaccine, says Amanda Dempsey, MD, PhD, MPH, a member of the CHEAR Unit team.
What are some of the chief factors that are keeping women in the 18-26 age group from getting the HPV vaccine? Women in stable monogamous relationships may not realize that they still are at risk of acquiring HPV, observes Dempsey. "Even though they are not having new sexual partners, in this situation, they are still at risk" because the woman's partner might have had previous sexual partners, she states. "Also, some women who are already sexually active may think it is 'too late' to benefit from the vaccine, which it is not," Dempsey says.
Many women in the 18-26 age group are healthy and don't see a medical provider very frequently. However, they do see a gynecologist with some regularity, notes Dempsey. "Gynecologists have historically been less likely to offer vaccines as part of their clinical practice that other primary care providers; however, with the HPV vaccine, there is a growing interest among gynecologists to provide vaccines, or at least the HPV vaccine," states Dempsey.
Financial constraints may be an important factor in access to the HPV vaccine, says Dempsey. It typically costs $360 for the three-shot regimen.3 While about 98% of privately insured Americans get at least some coverage for the HPV vaccine, more than 46 million Americans are uninsured. More than 25% of those uninsured include women ages 19-26, whose age excludes them from the publicly funded Vaccines for Children (VFC) program.3
Many young adult women do not have health insurance that covers vaccines, says Dempsey. They may be "in between" their parents' insurance and have yet to obtain employment health benefits, she notes. "Also, once you reach age 18, a person is no longer qualified for the VFC program, which provides free vaccine to under/uninsured children under this age," observes Dempsey. "Some states have programs that can provide some vaccines to people 18 and older, but this varies substantially from state to state, and by vaccine."
Research is looking into use of the quadrivalent vaccine in males; Merck is expected to submit data for such use of the vaccine in 2008 to the FDA.6
References
- Markowitz L. HPV vaccines. Issues for ACIP consideration. Presented at the Advisory Committee on Immunization Practices. Atlanta; February 2008. Accessed at www.cdc.gov.
- Dunne E. Epidemiology of HPV infection. Focus on older women. Presented at the Advisory Committee on Immunization Practices. Atlanta; February 2008. Accessed at www.cdc.gov.
- Springen K. Why are HPV vaccine rates so low? Newsweek, Feb. 25, 2008. Accessed at www.newsweek.com/id/115329.
- Saslow D, Castle PE, Cox JT, et al. American Cancer Society Guideline for human papillomavirus (HPV) vaccine use to prevent cervical cancer and its precursors. CA Cancer J Clin 2007; 57:7-28.
- Dempsey AF, Gebremariam A, Koutsky LA, et al. Using risk factors to predict human papillomavirus infection: Implications for targeted vaccination strategies in young adult women. Vaccine 2008; 26:1,111-1,117.
- Hoffman J. Vaccinating boys for girls' sake? The New York Times, Feb. 24, 2008. Accessed at www.nytimes.com.
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