Vaccination against human papillomavirus

The debate surrounding the HPV vaccine1 might be characterized by 2 slogans: “Just do it” versus “What's the hurry?” The HPV vaccination program's supporters see any potential reductions in cervical cancer deaths as sufficient justification for starting the program immediately. Others point to unanswered questions about the real-world costs and the effectiveness and safety of a vaccination campaign, and they caution that we need to wait for better data.

There is a natural quasi-experiment on which Canada can capitalize, with 4 provinces (Ontario, Nova Scotia, Prince Edward Island, and Newfoundland and Labradour) serving as the early intervention group and the remaining provinces and territories as the delayed control group. As health authorities across the country set up patient registries to systematically track and monitor the results of their HPV vaccination programs, we can start to answer vital real-world questions about the uptake of vaccination programs, the rates and severity of adverse effects and the impacts of the new vaccination initiatives on rates of Pap smear screening. Jurisdictions in the delayed control group can use the lessons learned by the early intervention group to refine their programs before they are launched, and we will be able to compare the experiences of the 2 groups on a number of factors.

Using controlled delays to evaluate the effectiveness of health programs is not new. In 1946, when faced with a dire shortage of streptomycin and a large number of patients with tuberculosis, British authorities randomly assigned patients to early or delayed intervention groups.2 The drug shortage coupled with the scientific uncertainty about the overall benefits and risks of streptomycin, created an experimental situation and thus produced vital information to optimize treatment.

Implementing HPV vaccination programs at different times in Canada may not be the ideal “organized implementation infrastructure”3 for which some in the oncology community have called, but why not let pragmatism rule the day? We can learn from the experience of early adopters and gather and analyze new real-world data on the vaccination programs as they become available. For any rigorous evaluation program to be successful, health planners must coordinate their activities and set up the right data systems to capitalize on Canada's natural quasi-experiment.