This was a preliminary look at the nature of exemptions to school-entry vaccination laws in the Canadian setting, with a descriptive examination of Ontario exemptions based upon newly available aggregate data. In the presence of a limited scope of compulsory immunization laws in Canada, the overall exemption rate is low. Non-medical exemptions exceed medical exemptions, however, and younger children appear to have been more frequently exempted for non-medical reasons.
The ability to link these data with individual-level characteristics is not yet possible and reflects continuing gaps in public health reporting (Manuel 2006
) and the evolving state of immunization information systems (Toronto 2009
). Longitudinal individual-level data, models or both, collated with geographic distribution of exemptions, will be important to ascertain discrete estimates of personal and population risk related to opting out in Ontario. Nonetheless, the preliminary findings presented here are of public health and policy concern.
First, in the presence of continuing underimmunization with regard to national childhood coverage targets (Frescura 2007
), increased propensity towards non-medical exemptions in communities constitutes another barrier to achieving the levels of immunization coverage required to prevent disease transmission. Our findings corroborate other studies demonstrating an increasing rate of specifically non-medical exemptions claimed by parents on behalf of their children (Salmon et al. 2005
). Given that children with non-medical exemptions tend to be geographically clustered (Salmon et al. 1999
; Calandrillo 2004
; Omer et al. 2009
), such findings present potential risks for transmission of disease and consequently, an impact on population health. As recently as 2005, for example, a large outbreak of rubella (over 300 cases) occurred in a religious community in Ontario opposed to immunization, including 10 cases in pregnant women with the associated risk of congenital rubella syndrome in their newborns (National Advisory Committee on Immunization 2006
Second, we reflect upon the notion that even in the presence of limited state intervention into individual behaviour, the finding that younger children (born in 1998 and after) appear to have been exempted much more frequently for non-medical reasons suggests that, consistent with trends such as for MMR vaccination in the United Kingdom, Canadian parents too may be increasingly weighing perceived personal risk over personal and population benefit when it comes to making decisions about immunization for their children. Accordingly, effective and accurate communication of vaccination risk has been a dominant concern among immunization advocates.
Finally, a detailed examination of the ethical and legal issues related to non-medical exemptions in Canada is beyond the scope of this paper, but a few issues are presented here for future consideration. Compulsory immunization policies present tensions and trade-offs between individual rights and liberties and societal goals. Non-medical exemptions are one way of dealing with these trade-offs. Different jurisdictions have interpreted these trade-offs differently, however, and a rethinking of this policy issue is perhaps warranted in Canada. In the United Kingdom, for example, in the wake of significant decreases in childhood MMR vaccination coverage, the issue of compulsory vaccination was revisited and not recommended by certain analysts (Salmon et al. 2006
). In contrast, in the United States, where compulsory school-entry immunization laws exist in all states, non-medical exemptions are not uniform; many states do not allow philosophical/conscientious exemptions, and this approach has not been found to be unconstitutional (Calandrillo 2004
). It has been argued that compulsory immunization laws “demonstrate a public commitment to vaccination” (Salmon et al. 2005
). If policy makers were to update (and potentially extend) compulsory school-entry vaccination laws in Canada, such developments should be incumbent upon a more in-depth policy discussion regarding a national responsibility to ensure a reliable supply of safe and effective vaccines for collective immunization programs (Verweij and Dawson 2004
; Salmon et al. 2006