The Alliance for Cervical Cancer Prevention Welcomes Progress in HPV Vaccine Development
Preliminary findings from an ongoing study of a vaccine to prevent human papillomavirus (HPV) 16 infection suggest that important steps are being made toward eradicating cervical cancer as a global killer of women (Koutsky 2002). The vaccine, which targets the HPV type found in half of all cervical cancers in many regions of the world, was 100 percent effective in preventing persistent HPV 16 infection among women followed for 17 months. Developing an effective vaccine to prevent infection with the most virulent cancer-causing types of HPV (types 16 and 18, and possibly 31, 33, and/or 45) will have profound implications for the health of women worldwide. Indeed, it is an exciting time in the field of cervical cancer prevention and the Alliance for Cervical Cancer Prevention (ACCP) welcomes this good news.
While cervical cancer is an important global health problem, it is particularly hard-hitting in developing countries where some 80 percent of the 244,000 annual deaths occur and where cervical screening efforts often are not well organized or effective in reducing mortality rates. Considerable progress is being made toward clarifying appropriate, effective, and sustainable strategies for screening and treating women for precancerous lesions in low-resource settings. The ACCP is committed to furthering this progress and looks forward to applying its expertise and experience, and involving its networks to support HPV vaccine and other cervical cancer prevention efforts.
Prophylactic HPV vaccines currently under development include Merck Laboratory’s quadrivalent vaccine against types 16 and 18, as well as types 6 and 11 which cause genital warts. GlaxoSmithKline is currently developing a vaccine against HPV 16 and 18. Studies are examining vaccine efficacy the United States and Latin America under optimal clinical research conditions. While preliminary findings are promising, the road to effectively introducing proven vaccines under the conditions found in most developing countries is long. Disease epidemiology, infrastructural constraints, and sociocultural norms all present unique challenges to the successful introduction of vaccines in low-resource settings. For example, it is likely that to be effective, an HPV vaccine will need to be administered to girls or young women prior to their sexual debut over a period of several months. Parents, health care providers, policymakers, community leaders, and girls themselves may have concerns and sensitivities about offering a vaccine to prevent the development of a sexually transmitted disease to these people. Research among these key stakeholders on acceptability of a test of this nature will be essential.
Because there is regional (and even country-level) variation in the prevalence of different oncogencic HPV types, an effective vaccine must be able to prevent the HPV types linked to cervical cancer in given settings. Vaccines must be robust enough to withstand conditions common in many developing countries. Because a vaccine will likely have to be administered over a period of several months, health care systems must have and maintain information systems making it possible to recall vaccine recipients for booster shots. And finally, for vaccines to be accessible worldwide, manufacturers must be motivated to market them at costs that are affordable in poor countries.
Many of the challenges inherent to testing or introducing vaccines in developing countries are similar to the difficulties of developing effective cervical screening programs. The ACCP’s extensive experience in assessing and strengthening health care systems, training health care providers, involving communities in developing interventions and ensuring intervention acceptability among users, policymakers, health care providers, and others positions the Alliance well to facilitate the accelerated introduction of HPV vaccines.
An inexpensive, safe, acceptable, and effective prophylactic vaccine against cancer-causing types of HPV has the potential to greatly reduce cervical cancer incidence and mortality worldwide. But this will not eliminate the need for effective and accessible cervical screening services for many years to come. As clinical trials are launched in developing countries, effective screening services will need to be in place to assess HPV prevalence at baseline and at short- and medium-term post-intervention outcomes in experimental and control groups. Because prospects for developing a therapeutic vaccine are currently only at the conceptual stage, a large global cohort of women already infected will continue to need screening for many years to come. In addition, people who inevitably won’t have access to vaccination will require screening. For these reasons, effective screening strategies will need to be in place for several decades beyond the time that an HPV vaccine is made available, particularly one that is developed for early adolescents.
Concurrent advances in cervical cancer screening and treatment and in developing HPV vaccines appropriate for low-resource settings offer an excellent partnership of progress (Blumenthal 2002). The eventual introduction of a safe, effective, acceptable, and affordable HPV vaccine to developing countries as a first line of protection has exciting implications in the field of cervical cancer prevention. Strengthening efforts in these countries to screen for and treat precancerous lesions is a complementary and indeed essential part of this effort. The ACCP looks forward to contributing to these endeavors to safeguard the lives of women worldwide.
Koutsky LA, Ault KA, Wheeler CM, et al. A controlled trial of a human papillomavirus type 16 vaccine. N Engl J Med 2002 Nov 21;347(21):1645-51.
Blumenthal P. Immunization against cervical cancer: who? when? where? Medscape Women's Health eJournal, Nov 2002.
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