Measles Immunization in Saskatchewan - Coverage Disparities and Challenges to Achieving Herd Immunity Threshold
Date
2019-09-19
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
0000-0003-2086-7923
Type
Thesis
Degree Level
Doctoral
Abstract
Adequate immunization offers protection against vaccine-preventable communicable diseases. However, after being absent for years, measles is recurring in the province of Saskatchewan, Canada. Measles is not endemic in Canada. There could be factors that make the province vulnerable to recurrent outbreaks. This study evaluated the disparity in immunization coverage for measles among children aged 12 to 24 months in Saskatchewan health regions between 2002 and 2013 and explored factors affecting measles immunization coverage rates and the barriers to the achievement of herd immunity threshold.
The research, a mixed methods design, used a cross-sectional total sample data of 24 month old clients of measles vaccination on eHealth Saskatchewan Immunization Registry platform between 2002 and 2013. A total of 169,852 two-year-olds were included in the study in the quantitative component. 65.5% lived in the ‘city’ (urban) and 31.3% in ‘not city’ (rural) locations. The study found a progressive increase in coverage rate from 56.32% in 2002 to 73.21% in 2013 with an Average Annual Percentage Change (AAPC) of 2.4 (C.I. 2.0 – 2.9, P < .005). Coverage rates increased progressively for both rural and urban locations, however coverage was higher in rural than urban locations. There was a progressive increase in the coverage rates for socio-economic deprivation quintiles 1 (least deprived) and 5 (most deprived) for both age groups studied. The coverage rates were higher in the socio-economic deprivation quintile 1 (least deprived) than in 5 (most deprived) for both on-time for first dose at 1-year and on-time for second dose at 2-year age groups between 2002 – 2013; however, the AAPC for socio-economic deprivation quintile 5 were higher both at the level of the province as well as among the RHA peer groups, an indication of progressive reduction of disparity from 2002 -2013 between the most and the least deprived groups. In-depth key informant semi-structured two-phase interviews with nine each of immunization coordinator/frontline vaccination staff and medical health officers uncovered enablers and barriers to improved uptake.
Barriers identified were access-related issues, caregivers’ fears and hesitancy, anti-vaccination challenges, and systems and resource limitations. Strategies to improve coverage range from access improvement while reducing missed opportunities, increasing awareness and health care provider education, continuing reminder calls, as well as involvement of the primary health care physicians for client reminders on a general approach. Targeted approaches will increase community engagement and communications to address the issue of hesitancy and anti-vaccination movements, and work on mitigating social determinants of health.
This research showed that individuals from deprived communities are less likely to achieve a higher coverage rate for measles immunization if the drivers of low uptake are not addressed. Continuous monitoring of coverage rates is essential to ensure higher uptake for better health outcomes. While socio-economic inequalities in measles immunization uptake can be a major public health problem in industrialized countries, uncovering factors responsible may provide platform for improved collaboration of interdisciplinary teams for immunization delivery efficiency, constructive stakeholder engagement and integrating clients and other systems for research.
Description
Keywords
Population health, Public health, MMR, MMRV, Health inequalities, Health inequity, Health policy, Socio-economic deprivation, Measles immunization
Citation
Degree
Doctor of Philosophy (Ph.D.)
Department
Community Health and Epidemiology
Program
Community and Population Health Science