Examining measles, mumps, and rubella (MMR) immunization uptake in Saskatoon: Can neighbourhood characteristics predict coverage rates?
Avis, Kyla Dawn
Immunization programs have proven to be one of the most successful public health initiatives in Canada yet continuous monitoring of coverage rates is essential to ensure high uptake and the continued success of these programs. Prior to this study, Saskatoon Public Health Services (PHS) were limited to manual calculation of coverage rates and trends and were unable to examine immunization uptake by neighbourhood. The purpose of this study was to utilize newly available data from the Saskatchewan Immunization Management System (SIMS) to examine city and neighbourhood uptake of the Measles, Mumps, and Rubella (MMR) vaccine. Once neighbourhood coverage rates were calculated, the project centred on using quantitative neighbourhood level data to determine if the neighbourhood variables of interest could significantly contribute to the explanation in variation of up-todate immunization coverage in Saskatoon. The study looked at 10, 287 two year-olds in Saskatoon between 1999 and 2002. The findings revealed immunization rates were relatively stable during this period. Of the approximately 90% of children who were immunized each year about 70% were considered up-to-date while approximately 20% were considered delayed or incomplete. However, significant disparities were found to exist at the neighbourhood level with areas of social and economic disadvantage having lower rates of total, complete, and up-to-date immunization uptake compared to areas of greater social and economic wealth. A slight downward trend in total immunization uptake was also noted in both the city of Saskatoon and high uptake neighbourhoods. Interestingly, high uptake neighbourhoods were also found to have the highest levels of social and economic advantage. Multivariate linear regression, used in the second phase of the analysis, revealed 80.6% of variation in up-to-date immunization uptake in Saskatoon could be explained by the proportion of single mothers and the proportion of vehicles registered in ,the neighbourhood. These findings are supported by the literature and may indicate the presence of real or perceived barriers to immunization for some families in Saskatoon. Limitations of the study include: the quality of the SIMS data, general limitations of ecologic designs, and problems with child mobility within and outside of the city. The issue of mobility likely resulted in the overestimation of coverage rates in some neighbourhoods and underestimation in others even though measures were taken to mitigate the effects of potential misclassification. Six recommendations were devised in an attempt to identify possible directions for future research and to improve the provision of immunization services for all areas of the city with particular attention focussed on high-risk neighbourhoods. It is hoped the findings of this study and recommendations provided will assist PHS in their continued efforts to improve immunization uptake in Saskatoon and throughout the entire region.