Two trials recently demonstrated that a single dose of the bivalent human papillomavirus (HPV) vaccine Cervarix, created by the GlaxoSmithKline group, may provide just as much protection against HPV-16/18 infections as the traditional schedules for two and three doses, researchers said Wednesday.
HPV-16/18 infections are responsible for approximately 70 percent of cervical cancer cases.
"Our findings question the number of HPV vaccine doses truly needed to protect the majority of women against cervical cancer, and suggest that a one-dose schedule should be further evaluated,” National Cancer Institute (NCI), National Institutes of Health Investigator Aimee Kreimer said. “If one dose is sufficient, it could reduce vaccination and administration costs as well as improve uptake. This is especially important in less developed regions of the world where more than 80 percent of cervical cancer cases occur.”
Kreimer is co-lead author of the trials with
University of New Mexico Health Sciences Center Professor
Cosette Wheeler. The findings were published Wednesday in The Lancet Oncology.
"Using existing data, we showed that a single dose of the bivalent HPV vaccine may be sufficient to substantially reduce cervical cancer incidence,” Wheeler said. “Yet, a new randomised study will be needed to confirm these findings and move the field forward. Additionally, duration of protection from a single dose must be demonstrated beyond four years."
Dr. Julia Brotherton from the Victorian Cytology Service Registries in Melbourne, Australia, commented on the findings.
"If HPV vaccines could be delivered as one dose, while retaining their efficacy against the most oncogenic HPV types 16 and 18, the global burden of cervical cancer would substantially decrease,” Brotherton said. “Data from studies have shown how effective one-vaccine dose campaigns can be in even the most resource-poor settings (eg, meningitis A vaccines in sub-Saharan Africa). We can imagine that such campaigns could happen every 5-10 years with the aim of vaccination of, for example, all 9- (to) 14-year-old girls with one dose of the HPV vaccine. This campaign would not need ongoing resources to sustain annual vaccination programs against HPV in settings with many pressing health priorities and small numbers of health care workers."