Study aims to optimize HPV vaccine dosing schedule

12 December 2012

Canadian researchers are seeking 8,666 teenage girls across the country for a new MSFHR-supported national study opening this month that will determine whether two or three doses of the vaccine Gardasil provide similar protection against human papillomavirus (HPV).

HPV infections cause nearly all cases of cervical cancer, which is the second most commonly diagnosed cancer in women worldwide.

The study is funded by MSFHR as part of a long-term HPV vaccine evaluation project. It builds on earlier research funded by MSFHR at the request of the provincial health officer that demonstrated the effectiveness of a two-dose vaccine regimen in conferring immunity. Contributions to the study have also been received from the BC Centre for Disease Control Foundation for Population and Public Health, and the HPV vaccine evaluation and research fund set up by the Governments of British Columbia, Alberta, Saskatchewan, Manitoba, New Brunswick, PEI, Newfoundland, Labrador, Yukon, and Nunavut. Additional funding will be provided by the Quebec Ministry of Health and Social Services.

“The HPV vaccine is very effective at providing immunity against the disease,” says Dr. Simon Dobson, the study’s lead co-investigator. “If we find that two doses are effective, then it would mean fewer needles for girls receiving the vaccine, as well as cost savings for the health care system. Earlier studies have shown that two doses of Q-HPV vaccine are as protective as three doses for up to 36 months. We want to ensure that over the longer term, two doses remain effective.”

Dr. Dobson is a clinical investigator at the Child & Family Research Institute, an attending physician in pediatric infectious diseases at BC Children’s Hospital, and a clinical associate professor in the Department of Pediatrics at the University of British Columbia (UBC).

The study will last up to 10 years, varying from girl to girl, and 8666 girls born between 1997 – 2000 will be recruited to participate in the study from five centres across Canada:

  • The Vaccine Evaluation Centre at the Child & Family Research Institute at BC Children’s Hospital in British Columbia is recruiting 3609 participants
  • Alberta is recruiting 1445 participants
  • Québec is recruiting 2167 participants
  • Nova Scotia and PEI are together recruiting 1445 participants

Half of the participants will have received two doses of the quadrivalent HPV (Q-HPV) vaccine and half will have received three doses, mostly in publicly provided immunization programs in the various provinces.

Girls participating in the study will complete an annual survey designed to address risk factors for getting HPV disease. Beginning in the year that they turn 15 and continuing for five consecutive years, girls will self-collect vaginal swabs and send them to the study lab, which will test for HPV and determine whether the number of doses received to date have offered adequate protection. There are also two optional blood samples that will be tested for levels of immune protection against HPV.

The study is designed to assess risk for HPV disease, HPV prevalence, and the levels of protection provided by two doses compared to three doses of the vaccine. It aims to answer these questions:

  • Are two doses of HPV vaccine good enough to continue to provide protection?
  • What level of HPV disease is present in the vaccinated population?
  • Is there a difference between the groups that have had two versus three doses of HPV vaccine?

To participate in the study, visit or call:
604.875.2000 ext. 6501
toll-free: 1.866.502.2424

The study’s co-principal investigators are Dr. Gina Ogilvie and Dr. Mel Krajden. Dr. Ogilvie is the medical director, Clinical Prevention Services at the BC Centre for Disease Control (BCCDC) and an associate professor in the Faculty of Medicine at UBC. Dr. Krajden is the medical director, Hepatitis Services at BCCDC and a professor, Pathology & Laboratory Medicine at UBC. Provincial investigators are Dr. Jim Kellner at the Alberta Children’s Hospital, Dr. Marc Dionne, Dr. Chantal Sauvageau and Dr. Marie-Helene Maynard in Quebec and Dr. Shelly McNeil for the Atlantic provinces.