Data from Ontario show early benefits from the human papillomavirus (HPV) vaccine in young girls, according to a new study by researchers at Queen's University and McGill. The HPV vaccine, which protects against four types of HPV shown to cause cervical cancer and anogenital warts, is offered free through school-based programmes to young girls across Canada. Despite the fact the vaccine is free, vaccine rates are lower than expected in a number of regions, in part because parents perceive their daughter's level of sexual activity as low at young ages.
"We observed a large and significant reduction in cervical dysplasia, a precursor to cervical cancer, in girls as young as 14-17 years," say Dr Leah Smith and Dr Linda Lévesque, researchers with the Institute for Clinical Evaluative Sciences (ICES) at Queen's University. McGill professors Jay Kaufman, from the department of epidemiology, biostatistics and occupational health (EBOH), and Erin Strumpf, from EBOH and the department of economics, co-authored the study, which also found the vaccine is starting to decrease genital warts in this population.
"The fact that these benefits were observed in such a young age group strengthens current recommendations that vaccination should not be delayed," says Smith, lead author on the study.
This study followed 260,493 girls, half of whom were eligible for Ontario's publicly funded Grade 8 HPV vaccination programme in its first two years (2007/08 and 2008/09). Researchers found that among the 2,436 cases of cervical dysplasia documented between Grades 10 to 12, 44% fewer cases occurred in eligible girls who received the vaccine. The research showed that one case of cervical dysplasia was prevented for every 175 eligible girls vaccinated.
"Although the vast majority of cases prevented by the vaccine would not have progressed to cervical cancer, given the burden of cervical dysplasia on the emotional and physical well-being of girls as well as on the health-care system, these early reductions are nevertheless of great importance," says Lévesque.McGill University material Pediatrics abstract