Extended HPV Vaccine Schedule Seems Effective
TUESDAY April 12, 2011 -- Giving doses of human papillomavirus (HPV) vaccine over a longer-than-normal period of time may prove an effective way to make the vaccine available to more females in poorer nations, a new study suggests.
HPV is a transmittable virus and the primary cause of cervical cancer, which kills about 275,000 women worldwide each year. About 88 percent of those deaths occur in developing nations, according to background information in the study.
"Combined with continued strengthening of simple evidence-based screening and treatment approaches, effective HPV vaccine programs could reduce cervical cancer rates in developing countries to the low levels currently observed in many developed countries," said Dr. Kathleen M. Neuzil, of PATH, a nonprofit organization located in Seattle whose stated mission is to improve global health, in a PATH news release. "One challenge to broadly implementing HPV vaccination programs in developing countries will be delivering the currently recommended three doses of vaccine to adolescents within six months (dosing schedules at 0, 2, and 6 months or at 0, 1, and 6 months)."
Even in countries where these dosing schedules are feasible, alternative dosing schedules may offer advantages such as lower cost (the vaccine could be given along with other health services) and increased coverage due to greater convenience for girls and their families or for vaccination teams, the study authors noted.
In this study, the researchers looked at four different dosing schedules used to give HPV vaccine to 903 adolescents girls at 21 schools in Vietnam. The doses were given according to a standard schedule of 0, 2 and 6 months or one of three alternative schedules (0, 3 and 9 months; 0, 6 and 12 months; or 0, 12 and 24 months).
The girls in the alternative dosing schedule groups developed antibody concentration levels similar to the girls in the standard dosing group, and no serious adverse events were reported.
The study findings are published in the April 13 issue of the Journal of the American Medical Association, a theme issue on infectious diseases and immunology.
"The similarity of the immunogenicity and reactogenicity profiles of the HPV vaccine reported from this predominantly ethnic minority population in a low-resource area of Vietnam and other populations throughout the world is reassuring and supports more widespread introduction of the vaccine. The World Health Organization acknowledges that programmatic constraints must be considered in the decision to commence national HPV immunization programs. The option of delivering HPV vaccine on flexible schedules will allow countries to minimize costs and maximize feasibility according to local vaccination practices," Neuzil's team concluded.
The U.S. National Cancer Institute has more about HPV vaccination.
Posted: April 2011