Human Papillomavirus Vaccine Inaccuracies

Although Maine et al. provided a comprehensive overview of the state of cervical cancer prevention today,¹ their article presented some inaccuracies and tended to downplay the benefits of vaccination and magnified its challenges. For example, the authors failed to acknowledge that immunization has much less socioeconomic variation than screening does and has very little evidence of gender bias in particular.

More importantly, their calculations assumed that the dropout rate for second and third doses of vaccine will be 15% at each step (28% in total), similar to the estimated dropout rates for women making multiple visits for screening and treatment. In demonstration projects in India, Peru, Uganda, and Vietnam, where human papillomavirus (HPV) vaccination was implemented by existing immunization program staff, dropout rates from first to third dose ranged from 0.5% to 17.6%, and all but one were less than 8%²; the rates were generally lowest with school-based vaccination. Furthermore, the authors suggested that because it requires intramuscular injection, the HPV vaccine will be more expensive than other vaccine programs—an odd claim, given that most Expanded Program on Immunization vaccines are also injectable.

Maine et al. raised the “humanitarian” concern that with HPV vaccination, older women “will essentially be left to their fate.”^{1(pp1551-1552)} In fact, the contrary is true. Vaccination and its promotion—including the message that screening must still be provided—are creating a demand for screening and a recognition that a comprehensive approach is essential. Although the authors believe that governments cannot do both, several countries are already implementing both screening for older women and vaccination for young adolescent girls. Timetables for scaling up these strategies may vary according to local needs. The World Health Organization (WHO), the United Nations Population Fund (UNFPA), the International Federation of Gynecology and Obstetrics (FIGO), and other international organizations recommend a comprehensive approach. Investments are clearly needed in both screening and vaccination.

Countries will need to decide for themselves the best place to start, depending on what they already have in place. Where disease burden is high enough and the immunization program is already functioning well, HPV vaccine is a sensible part of any comprehensive prevention program, especially with GAVI Alliance support for vaccine purchase. In Rwanda, for example, they launched HPV vaccination nationwide in April 2011, while continuing to work on a national screening strategy. Countries have important and difficult decisions to make about allocating scarce resources; accurate and balanced information will be critical in making those decisions.