Our results show that all ethnic groups, with the exception of black Canadians, had significantly higher uptake of influenza vaccination than white Canadians. Variations in coverage levels persisted even after adjusting for other determinants of vaccine uptake, which suggests that there may be unique barriers and misconceptions influencing these groups differently.
Two recent systematic reviews that examined factors associated with vaccination for 2009 A (H1N1) pandemic influenza found that ethnicity was associated with vaccine uptake in the United Kingdom (UK), Australia and the US.18,19
Furthermore, our results concur with those from other studies that showed higher uptake of childhood vaccinations among certain ethnic populations.20,21
In a UK study involving children aged 18 months to 3 years, Mixer and colleagues found that Asian children were more likely to receive the measles–mumps–rubella (MMR) vaccine than black or white children.21
These differences were attributed to varying levels of exposure to mass media on the controversy surrounding the MMR vaccine, as well as the influence of family and health professionals on decisions about vaccinations. In addition, the authors suggested that “shielding” from negative media coverage, owing to language barriers and different levels of integration into British society, may have contributed to higher vaccine coverage in certain populations.
Our results could be related to the level of exposure to and support for antivaccination media, because it is unknown whether certain groups in Canada are more likely to be exposed to, or supportive of, such media. Further research is needed to understand exposure to antivaccination media by ethnicity, and whether this affects willingness to receive vaccinations.
Our results are similar to those of American studies that have documented ethnic differences in influenza vaccination among Asian populations.2–4,16,22,23
The 2008 Behavioural Risk Factor Surveillance Survey showed that influenza vaccination among Asian Americans aged 50 years or more was significantly higher than among people from the non-Hispanic white, non-Hispanic black and Native American groups, after adjusting for other variables.4
The reasons for this higher rate of coverage among Asian Americans are not well studied.
A recent survey involving students and staff at an Australian university found that, compared with participants from other regions, Asian-born respondents were significantly more likely to have anxiety concerning the 2009 A (H1N1) influenza pandemic, rate the situation as serious and change specific behaviours to comply with public health measures.24
During the past century, 2 influenza pandemics and the severe acute respiratory syndrome coronavirus have originated in Asia; the increased media exposure and precautionary actions resulting from these health events may have heightened awareness among Asian populations. In addition, the psychological impact on people who directly or indirectly experienced negative events as a result of these outbreaks may provide additional motivation to receive vaccinations. Furthermore, people who lived through both of the most recent influenza pandemics that originated in Asia would be at least 50 years old; in our study, the range of coverage among elderly participants was more than twice that of the respondents aged 12–64 years (i.e., 31% v. 14%). Similarly, estimates of coverage among Asian Americans aged 18–64 years and at high risk of infection with the influenza virus were close to the US national average for the 2006–2007 influenza season, but higher coverage was seen among Asian Americans aged 65 years and older.17
Currently, there is no efficient method to routinely assess ethnic disparities in influenza vaccination in Canada, because ethnic identifiers are generally not collected on vaccination records. Relying on data from the CCHS does not permit regional or annual estimates, because sample sizes are restrictive among ethnic minority groups.
Self-reported vaccination status is subject to response and recall biases, resulting in over-or underestimates of coverage. However, previous studies have validated self-reported influenza vaccination status.25–27
Ethnic categories were based on those of the CCHS questionnaire, and some groups were heterogeneous (e.g., black, white, South Asian, Latin American, multiracial/other). In an effort to avoid exacerbating this heterogeneity, we refrained from combining East Asian or Southeast Asian groups to assess the variability in coverage between these groups, given the pre-existing evidence of disparities.16
It was not possible to distinguish people identifying solely as Aboriginal in the CCHS data because Aboriginal people were not asked to state whether they also belonged to other ethnic groups. Therefore, some of the people in the self-identified Aboriginal group included in our study may be of multiracial heritage.
We did not control for status as a health care worker in our analysis, but we are unsure if this would have a significant impact on our results given that less than 7% of the population work in health occupations, and the proportions of people working in health-related occupations are similar between immigrants and nonimmigrants.28
Finally, although the CCHS is conducted in multiple languages, people with language difficulties may be less likely to participate. Because these people may have reduced access to information about vaccinations, coverage among ethnic minorities in this sample may have been overestimated. Language issues may also contribute to a higher response rate among the Aboriginal and white populations compared with other groups, resulting in a larger sample of both groups in this survey.
All ethnic groups in Canada, with the exception of black Canadians, had higher uptake of influenza vaccination than white Canadians. These differences remained significant even after controlling for sociodemographic characteristics and health status. These results suggest a public health concern that requires further validation and study to determine whether there are barriers to vaccination that are unique to black and white Canadians.
Our findings should not understate the importance of tackling issues of sociodemographics and access to health care that influence uptake and extend across all ethnic groups in Canada. To ensure optimal vaccine coverage, it will be important for public health to work with health care providers, clients and community-based organizations to understand the unique challenges and barriers that affect their communities, and to design appropriate interventions for different populations.