Why Girls Shouldn't Be Guinea Pigs

Quebec’s dispensation of the HPV vaccine is making a new generation of lab rats out of its young girls.

The Human Papillomavirus (HPV) is considered the most common sexually transmitted infection, with an estimated 75 per cent of sexually active people contracting it at some point in their lives. Most people who get HPV won’t even realize they’ve been infected because they won’t develop symptoms and the infection will usually clear on its own. In a few instances, however, HPV causes cervical cancer, which kills some 400 women in Canada every year.

Gardasil, a vaccine manufactured by Merck & Co., was designed to protect against four of the most common strains of HPV. Three years ago, the vaccine was approved by Health Canada for use in girls between the ages of 9 and 26. The market authorization was granted on the basis of twelve clinical trials involving over 21,000 individuals. These trials examined safety (whether the vaccine was harmful), and efficacy (whether the vaccine would protect against cancer). Four of these trials provided data on the efficacy of Gardasil in women aged 16 to 26. Blood tests were used to see if Gardasil was effective in helping the immune system create antibodies to fight off HPV, and pelvic exams were used to look for signs of cancer. Another trial involving 1,200 girls aged 9 to 15 did not include pelvic exams. Instead, assumptions about how well Gardasil protected against cervical cancer were based solely on antibody levels in the blood.

In March 2007, shortly after Gardasil was approved, the federal government pledged $300 million over three years for a national HPV vaccination program. This announcement generated considerable public controversy. Many commentators insisted there were too many unanswered questions about the vaccine’s effectiveness, optimal dosing, duration of protection, and adverse effects to green light a national vaccination program. Some went so far as to call the program “the biggest Canadian science experiment in decades” with thousands of Canada’s girls slated to be “the guinea pigs.”

The criticism prompted a formal response from the Chief Public Health Officer of Canada, David Butler-Jones, who wrote that "the suggestion that we, as public health officials would support a vaccine that would put the health, or worse, the lives, of girls and women at risk is an irresponsible one. The health and safety of Canadians is of paramount importance to me, and to public health officials across the country."

Yet the concern about “our girls” being used as “guinea pigs” now appears to be well-founded, at least with respect to thousands of girls in Québec. The Québec school-based HPV vaccination program was introduced last fall. Primarily out of convenience and saving costs, the vaccine is offered in Grade 4 at the same time as the combined Hepatitis B and A vaccine. Québec is the only place in Canada where the school-based HPV vaccination program is offered to girls who are nine years old (the typical age for children in Grade 4).

Québec’s program is also unique in its refusal to follow the three-dose regimen recommended not only by its manufacturer, Merck & Co., but also by the Canadian National Advisory Committee on Immunization. Both recommend that the HPV vaccine be administered in three doses over a six-month period, at zero, two and six months. In Québec, the first two doses are given in Grade 4 (one dose in the fall and one dose in the spring) with the third dose given five years later, in Grade 9.

Québec has gone ahead with its dosing regimen without robust research data to support it and with very limited data on the safety and efficacy of HPV vaccination in nine-year-old girls. Only 100 girls of this age were included in the original clinical trials.

So is the HPV vaccine effective when administered to nine-year-olds in a two-dose regimen with a booster dose at age fourteen? We don’t know the answer to this question, but in time, if the data from Québec are made available and analyzed, we may be able to generate a knowledgeable answer. This prospect, however, raises another question: Do parents in Québec understand that, in consenting to HPV vaccination for their nine-year-old daughters, they are in effect consenting to their daughters' participation in an experiment? Based on my review of the written information given to parents, I strongly suspect the answer is “no.”