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Seasonal influenza vaccination uptake in Quebec, Canada, 2 years after the influenza A(H1N1) pandemic
American Journal of Infection Control 42 (2014) e55-e59
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American Journal of Infection Control
American Journal of Infection Control
journal homepage: www.ajicjournal.org
Major article
Seasonal influenza vaccination uptake in Quebec, Canada, 2 years after the influenza A(H1N1) pandemic Eve Dubé PhD a, b, *, Dominique Gagnon MSc a, Marilou Kiely MSc a, Fannie Defay MSc b, Maryse Guay MD, MSc, FRCPC a, c, d, Nicole Boulianne MSc a, b, Chantal Sauvageau MD, MSc, FRCPC a, b, Monique Landry MD e, Bruno Turmel MD e, France Markowski BSc e, Nathalie Hudon MA Comm e a
Institut national de santé publique du Québec, Québec City, Québec, Canada Centre de recherche du CHU de Québec, Québec City, Québec, Canada c Université de Sherbrooke, Sherbrooke, Québec, Canada d Direction de santé publique de Montérégie, Longueuil, Québec, Canada e Ministère de la Santé et des Services sociaux du Québec, Québec City, Québec, Canada b
Key Words: Immunization Vaccination coverage Survey Flu
Background: A decrease in seasonal influenza vaccine uptake was observed after the influenza A(H1N1) pandemic in 2009. The goal of our study was to assess seasonal influenza vaccine uptake in 2011-2012, 2 years after the influenza A(H1N1) pandemic mass immunization campaign and to identify the main reasons for having or not having received the vaccine. Methods: A telephone survey using random-digit dialing methodology was conducted. Case-weights were assigned to adjust for disproportionate sampling and for nonresponse bias. Descriptive statistics were generated for all variables. Results: Seasonal influenza vaccine uptake was 57% among adults aged 60 years, 35% among adults with chronic medical conditions, and 44% among health care workers. The main reasons given for having been vaccinated were to be protected from influenza and a high perceived susceptibility to influenza, whereas low perceived susceptibility to influenza and low perceived severity of influenza were the main reasons for not having been vaccinated. Conclusions: An increase in seasonal influenza vaccine uptake was observed 2 years after the influenza A(H1N1) pandemic. However, vaccine coverage is still below the target level of 80%. More efforts are needed to develop effective strategies to increase seasonal influenza vaccine uptake. Copyright Ó 2014 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.
Annual vaccination is one of the most effective measures for preventing severe outcomes of influenza. The Canadian National Advisory Committee on Immunization recommends influenza vaccination for people at high risk of serious infection as well as for their contacts. In the province of Quebec, at-risk groups targeted by the publicly funded influenza vaccination program are infants aged 6-23 months; adults aged 60 years; individuals aged 2 years with chronic medical conditions (eg, cardiac and pulmonary disorders, diabetes, immune-compromised conditions, renal disease, and asthma); and people such as health care workers who, as part of their work or daily life, have frequent contact with people at * Address correspondence to Eve Dubé, PhD, Institut national de santé publique du Québec, 2400 D’Estimauville, Québec (QC), Canada G1E 7G9. E-mail address: [email protected] (E. Dubé). Conflicts of interest: None to report.
higher risk of complications from infection. Each year, a large-scale influenza vaccination campaign is organized and the vaccine is offered free of charge to targeted groups throughout the province in different settings such as mass-vaccination clinics, long-term facilities, as well as health care institutions. To promote vaccine uptake, public health authorities run a promotional campaign every year during the influenza season. For the 2011-2012 campaign, the slogan used was: “The flu spreads easily. Get vaccinated.” As part of the promotional campaign, the slogan was conveyed through different means such as posters and flyers as well as by television, newspaper, and radio ads. Despite these efforts, influenza vaccination coverage among groups included in the publicly funded program remains below the target level of 80%.1 For instance, during the 2007-2008 campaign, approximately 58% of Quebecers aged 60 years received the influenza vaccine.2 During the 2010 vaccination
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campaign (January-April), just following the mass vaccination campaign for pandemic influenza A(H1N1), the proportion of vaccinated people aged 60 years decreased to 36%. The seasonal influenza vaccine uptake during 2010 was also very low in other high-risk groups, with fewer than one-third of individuals with chronic medical conditions (32%) and of health care workers (21%) reporting having received the vaccine.3 However, influenza A(H1N1) pandemic influenza vaccine uptake was high, with 77% of individuals aged 65 years, 76% of adults with chronic medical conditions, and 85% of health care workers being vaccinated against pandemic influenza.3 The main objective of our study was to document if the decrease in seasonal influenza coverage rates observed for the 2010 campaign has persisted over time. METHODS Results presented here are drawn from the 2012 Quebec study on vaccination against seasonal influenza, pneumococcal infections, and measles (l’Enquête québécoise sur la vaccination contre la grippe saisonnière, le pneumocoque et la rougeole [EQVGPR], 2012),4 a cross-sectional study conducted by telephone among a representative sample of Quebec households. We focus only on the EQVGPR section related to influenza vaccination for which eligible respondents were aged 60 years or older, were adults with a chronic medical condition (eg, asthma, other chronic pulmonary disease, cardiac problems, diabetes, cirrhosis of the liver, chronic kidney disease, cancer, or other immune system problem), or were health care workers (eg, an employee or volunteer in a health care environment such as a hospital or a clinic). To measure vaccination coverage, validated questions from preceding surveys were used.2,3,5 Reasons for having or not having received the influenza vaccine and for not intending to receive it in the following influenza season (2012-2013) were collected using open-ended questions. Different questions were asked to assess the awareness of promotional messages regarding seasonal influenza (eg, having heard the message, remembering the message, or if the message influenced the respondent’s opinion or behavior). Standard sociodemographic variables were also collected. The survey instrument is available from the authors upon request. The sample was constituted using random-digit dialing methodology and was stratified to ensure representativeness of 16 out of 18 sociosanitary regions in Quebec (2 northern regions were excluded). A professional research and polling firm handled recruitment and data collection. The computer-assisted telephone interviews were carried out from March-May 2012. Interviews were conducted in French or in English according the participant’s preferred language. The EQVGPR study was approved by the Research Ethics Board of the Centre hospitalier universitaire de Québec (project No. C12-02-181). Expansion weights were assigned to ensure that the results were representative of the target population by adjusting for disproportionate sampling and nonresponse bias. Weighting was applied to each respondent in the sample based on sociodemographic characteristics drawn from the answers of respondents who agreed to participate but who were not eligible because of quotas already attained as well as from census data (detailed methodology for the weighting can be found elsewhere).4 Descriptive statistics were generated for all variables. For each estimate, 95% confidence intervals (CIs) were calculated. Comparison between vaccine uptake and other sociodemographic variables were done using c2 or Fisher exact tests as appropriate. For univariate analysis, a probability level of P < .05 was considered
statistically significant. The exact verbatim of the open-ended questions was transcribed by the interviewers and submitted to content analysis. Statistical analyses were performed using SAS version 9.3 (SAS Institute Inc, Cary, NC), whereas content analysis was first done using word processing software and then imported into SAS version 9.3 software. RESULTS The response rate for the EQVGPR was 48% and a total of 2,516 individuals aged 60 years, 2,289 individuals with chronic medical conditions aged 18-59 years, and 754 health care workers aged 1859 years participated in the study. A subgroup of respondents who completed the questionnaire pertaining to seasonal influenza vaccination and their characteristics are shown in Table 1. Among adults with chronic medical conditions, asthma was reported mainly by adults aged 18-49 years (69.5% vs 37.3% for adults aged 50-59 years), whereas cardiac disease and diabetes were reported more frequently by adults aged 50 to 59 years (25.7% and 26.1% for adults aged 50-59 years vs 5.6% and 13.2% for adults aged 18-49 years). Health care workers were mostly managers, administrative personnel, and support staff (24.1%). Other health professionals such as nutritionists, dentists, psychologists, occupational therapists, physiotherapists, health technicians, specialized educators, and social workers constituted 21.4% of the sample of health care workers. Seasonal influenza vaccination coverage rates For the 2011-2012 campaign, 56.6% of individuals aged 60 years reported having received the vaccine (95% CI, 54%-59%). Vaccine uptake was higher among individuals aged 65 years than among those aged 60-64 years (61.3% vs 44.9%; P < .0001). Seasonal influenza vaccine uptake was higher among respondents aged 6069 years with chronic conditions compared with others without chronic conditions (ages 60-64 years 56% vs 38%; ages 65-69 years 60% vs 50%; P < .05). Having chronic conditions did not influence influenza vaccine uptake among persons aged 70 years (68% vs 61%; P ¼ .08). No difference between sexes was found in vaccine uptake among people aged 60 years. Fewer than one-third (29.9%; 95% CI, 26.2%-34.7%) of adults aged 18-59 years with chronic medical conditions had received the influenza vaccine for the same period. A difference in vaccine uptake was also found between younger and older people with chronic medical conditions (40% for adults aged 50-59 years vs 25% for adults aged 18-49 years; P < .001). Within the 18-49 age group with chronic medical conditions, more women were vaccinated than men (29.2% vs 19.3%; P ¼ .05). No statistically significant differences were found in vaccine uptake among individuals having different types of chronic medical conditions. Seasonal influenza vaccine uptake was higher among individuals aged 60-69 years with chronic medical conditions compared with others without chronic conditions (P < .05). However, having a chronic medical condition did not influence influenza vaccine uptake among individuals aged 70 years (P ¼ .08). Finally, fewer than half of health care workers reported having received the influenza vaccine during the 2011-2012 campaign (43.5%; 95% CI, 37.4%-49.6%). By type of work, vaccine uptake was 32.4% for managers, administrative personnel, and support staff (95% CI, 21.6%-43.2%); 61.6% for nurses (95% CI, 49.5%-73.6%); 50.5% for patient care attendants (95% CI, 33.5%-37.5%), and 39.8% for other health professionals (95% CI, 27.0%-52.6%). Physicians were the health care workers with the highest vaccine uptake (89.2%; 95% CI, 75.3%-100%). In addition, vaccine uptake was significantly
E. Dubé et al. / American Journal of Infection Control 42 (2014) e55-e59 Table 1 Sociodemographic characteristics of study respondents*
Characteristic Individuals aged 60 y (n ¼ 2,516) Age 60-64 y 65 y Sex Male Female People living with CMCy 60-64 y 65 y Individuals aged 18-59 y with CMC (n ¼ 1,145) Age 18-49 y 50-59 y Sex Male Female CMC Asthma 18-49 y 50-59 y Chronic obstructive pulmonary diseasez 18-49 y 50-59 y Cardiac diseasesx 18-49 y 50-59 y Diabetes 18-49 y 50-59 y Cirrhosis of the liver 18-49 50-59 y Chronic kidney disease 18-49 y 50-59 y Cancer or other immune system problem 18-49 y 50-59 Health care workers aged 18-59 y (n ¼ 454) Age 18-49 y 50-59 y Sex Male Female Type of work Physician Nurse Patient attendantjj Other health professional{ Manager, administrative personnel, or support staff Volunteer Other Don’t know e refusal
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Main reasons for having or not having received the seasonal influenza vaccine
Unweighted n
Weighted %
795 1,721
28.5 71.5
978 1,538
45.3 54.7
298 846
39.1 49.2
595 550
66.3 33.7
455 690
47.5 52.5
408 209
69.5 37.3
55 78
8.9 13.1
59 121
5.6 25.7
64 147
13.2 26.1
5 5
1.2 1.0
17 22
2.9 4.1
82 126
12.0 20.9
224 230
72.7 27.3
77 377
20.1 79.9
20 104 66 84 119
3.9 19.1 16.4 21.4 24.1
<20 43 <20
2.4 12.0 0.8
CMC, chronic medical conditions. *Unweighted numbers represent the exact number of respondents in each group. Weighted numbers represent the proportion of these respondents in the overall sample after adjustment for disproportionate sampling and nonresponse bias. y Respondent could have indicated >1 disease. z Includes emphysema, chronic bronchitis, and cystic fibrosis. x Includes angina, high blood pressure, heart failure, and heart attack. jj Includes caregivers/home care workers. { Includes nutritionists, dentists, psychologists, occupational therapists, physiotherapists, health technicians, specialized educators, and social workers.
higher among health care workers having frequent contact with patients (eg, nurses, physicians, patient care attendants, and other health professionals) when compared with those without frequent contact (eg, managers, administrative personnel, and support staff) (53% vs 32%, respectively; P ¼ .0019).
Table 2 presents the main reasons for having received or not received the influenza vaccine during the 2011-2012 campaign. The 3 most frequent reasons for being vaccinated against influenza among individuals aged 60 years were self-protection, a generally positive attitude regarding vaccination, and social responsibility (eg, thinking vaccination is a duty) as well as considering oneself an at-risk person due to type of work, presence of medical conditions, or travel considerations. Considering oneself an at-risk person and self-protection were the main reasons for vaccination reported by individuals aged 18-59 years with chronic medical conditions as well as by health care workers. Among all groups, the main reasons for not having received the seasonal influenza vaccine were low perceived susceptibility to influenza or low perceived severity of influenza, lack of interest, time, or information, and fear of side effects. Of note is the fact that 10.4% of individuals aged 60 years (95% CI, 8.0%-12.9%), 7.3% of individuals with chronic medical conditions (95% CI, 4.3%-10.3%), and 12% of health care workers (95% CI, 4.9%-19.2%) mentioned not having received the influenza vaccine because of a generally negative attitude toward medication and vaccines. Intention to receive the seasonal influenza vaccine during the next vaccination campaign Sixty-two percent of individuals aged 60 years, 41% of individuals with chronic medical conditions, and 54% of health care workers said they intended to be vaccinated during the next season. Among the 3 groups, the main reason for not intending to be vaccinated was a low perceived susceptibility to influenza or a low perceived severity of the disease (data not presented). The intention to be vaccinated during the next season was higher among people who had received the vaccine during the 2011-2012 campaign compared with those who did not. Awareness of the seasonal influenza vaccine promotional campaign Fifty-seven percent of individuals aged 60 years (95% CI, 54.4%59.2%), 50.4% of adults with chronic medical conditions (95% CI, 46.2%-54.6%), and 63% of health care workers (95% CI, 56.6%-68.8%) remembered having seen or heard the slogan of the promotional campaign. However, the majority of individuals in all groups reported that the slogan had no influence on their decision to get vaccinated (78% of adults aged 60 years [95% CI, 75.1%-80.5], 81% of adults with chronic medical conditions [95% CI, 76.6%-85.3%], and 79% of health care workers [95% CI, 71.9%-85.9%]). A minority mentioned that the slogan had a negative influence on their decision to get vaccinated against influenza (4% of adults aged 60 years [95% CI, 2.7%-5.0%], 2% of adults with chronic medical conditions [95% CI, 0.8%-3.7%], and 1% of health care workers [95% CI, 0.2%-2.8%]). There was no statistically significant difference in seasonal vaccine uptake between individuals who reported having seen or heard the slogan and those who did not. However, vaccine uptake was higher among people who mentioned that the slogan had a positive influence on their decision to get vaccinated. Indeed, the vaccine uptake among individuals aged 60 years who stated that the slogan had a positive influence on their decision was 81% compared with 50% for those who reported negative or no influence (P < .0001). The findings were similar for adults with chronic medical conditions (vaccine uptake was 61% among individuals who reported positive influence of the slogan vs 27% for those who reported negative or no influence; P < .0001) and for health care workers (72% vs 41%; P ¼ .0017).
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Table 2 Main reasons for having received or not received the seasonal influenza vaccine during the 2011-2012 influenza vaccination campaign*
Reason For being vaccinated Protection of oneself General positive attitude about vaccination/social responsibility Considering oneself at risk Recommendation to receive the vaccine Protection of others For not having received vaccination Low perceived susceptibility to influenza or severity of the infection Lack of interest/lack of time/lack of information Against medication and vaccines Fear of side effects Low perception of vaccine efficacy Doubts regarding vaccine efficacy
60 y % (95% CI)
18-59 years with CMC % (95% CI)
Health professionals % (95% CI)
50.0 20.7 13.8 10.0 4.0
(46.7-53.3) (18.0-23.3) (11.7-16.0) (8.0-12.0) (2.9-5.2)
28.6 5.2 46.9 5.1 11.6
(21.9-35.3) (1.8-8.6) (39.8-54.1) (2.6-7.7) (7.3-16.0)
22.9 9.7 53.4 1.3 10.7
(16.0-29.8) (3.0-16.3) (44.7-62.0) (0.0-2.7) (4.7-15.7)
46.4 16.9 10.4 10.0 4.8 4.0
(42.8-50.1) (14.1-19.8) (8.0-12.9) (7.8-12.1) (3.1-6.5) (2.6-5.4)
42.0 20.7 7.3 11.1 4.9 4.3
(36.9-47.2) (16.5-25.0) (4.3-10.3) (7.6-14.6) (2.6-7.2) (2.4-6.1)
27.7 25.0 12.0 17.1 6.8 4.8
(19.8-35.6) (16.3-33.6) (4.9-19.2) (9.3-24.9) (2.9-10.6) (1.6-8.1)
CMC, chronic medical conditions. *Reasons mentioned by <4% for >1 group are not shown.
DISCUSSION Results of our study indicate that influenza vaccination coverage for targeted groups is still below the objective of 80%, ranging from 29.9% for adults with chronic medical conditions to 43.5% of health care workers and 56.6% for individuals aged 60 years. However, with vaccine uptake comparable to the 2007-2008 estimates,2 our results show that the decrease observed in seasonal influenza vaccination coverage following the mass vaccination campaign for influenza A(H1N1) pandemic influenza was not maintained over time. The particular context of the Quebec 2010 seasonal influenza vaccination campaign (which was carried out January-April only, just after the mass vaccination campaign against pandemic influenza) may be an explanation for the low vaccine coverage rates observed. The unwillingness of individuals to receive 2 vaccines against influenza during one season has been observed elsewhere.6 Indeed, a similar patternddiminution for the 2009-2010 campaign and a return to prepandemic vaccination coverage rates for the 2011-2012 campaigndwas also observed in other Canadian provinces and territories.7 Results of 2 large studies8,9 also suggest that the influenza A(H1N1) pandemic vaccination campaign did not negatively affect subsequent seasonal influenza vaccination rates. In fact, except for the 2010 campaign, seasonal influenza coverage rates are relatively stable over time in Quebec.2 Results of our study also show that the main reasons for not being vaccinated were related to a low perceived threat of influenza. On the other hand, people who received the vaccine shared motives of self-protection and protection of relatives and other atrisk persons as well as a high perceived susceptibility to influenza. In addition, intention to be vaccinated during the next campaign seems to be strongly correlated with vaccine status at the time of the survey. Reasons to accept or refuse the vaccine that we identified are congruent with results of most studies.10-13 For instance, past vaccination behavior has been identified as a determinant of vaccine uptake in numerous studies.10,12 In addition, in a systematic review of the determinants of influenza and pneumococcal vaccination in elderly populations, Kohlhammer et al11 indicated that the most common reasons for not having received influenza vaccination were the absence of risk perception, disbelief in the efficacy of vaccination, and the fear of side effects. This highlights the important role health care workers play in addressing patients’ doubts about the safety and effectiveness of the vaccine. Providers’ recommendations are an important determinant of influenza vaccine uptake.10,11,14 Findings of a review on determinants of nurses’ practices regarding influenza vaccination indicate that higher knowledge and positive attitudes toward
influenza vaccination were positively associated with vaccination coverage among nurses. There was also an association between nurses’ vaccination status and their reported promotion of vaccination with their patients.15 In this regard, the relatively low vaccine uptake among health care workers shown in our study is worrying, especially given the fact that free vaccines are available at the workplace and that strong recommendations to be vaccinated are made each year by professional associations and public health authorities. In addition, although many studies have shown that social responsibility is an important driver of health professionals’ decision to be vaccinated against influenza,16,17 most health care workers surveyed in our study indicated that they received the vaccine to protect themselves or because they considered themselves to be at risk for infection. This could be explained, at least partially, by the fact that we asked for only the main reason behind vaccine decisions. Awareness of promotional messages is a parameter frequently used to evaluate health-promotion campaigns.18 Results of our study indicate a mixed effect of the promotional campaign for seasonal influenza vaccination. Despite the fact that the majority of respondents did remember having seen or heard the slogan, no statistically significant difference was found in vaccine uptake between individuals who remembered the slogan and those who did not. Studies have shown that the type of source of vaccination information sought by patients is associated with vaccine decision making.14,19,20 For instance, results of a study conducted by Ashbaugh et al20 showed that individuals who did not intend to be vaccinated against pandemic influenza were more likely to report that the Internet was an influential source of information compared with government sources. Indeed, building trust in public health authorities’ recommendations is important. Government agencies need to be more proactive in providing evidence-based information, especially to at-risk groups. Efforts should also be made to increase the visibility of official Web sites and to be more present on social networking Web sites.20 Strengths and limitations Because Quebec has no central immunization registry, information on vaccination coverage can only be obtained through surveys. Monitoring vaccination coverage is essential in evaluating the capacity of the influenza vaccination program to attain its objectives. Moreover, our methodology allowed us to obtain important data on the reasons behind vaccine decision making that could not be recorded in an immunization registry. Indeed, one of the major strengths of our study is the wealth of data collected, both the large sample size, which includes all target groups, and in the
E. Dubé et al. / American Journal of Infection Control 42 (2014) e55-e59
type of data, which includes reasons behind vaccine decision making. Other strengths of our study were the use of random-digit dialing methodology for data collection and the use of case-weights to adjust for disproportionate sampling and for nonresponse bias. For these reasons, our estimates of influenza vaccine coverage are reliable and representative of the Quebec population. Our study has some limitations that need to be acknowledged. This study is descriptive. Although we looked at potential differences in vaccine uptake between respondents with different sociodemographic characteristics, no multivariate analysis was performed. The response rate for the entire survey was not optimal (48%), but remains satisfactory for a telephone survey.5 Nonresponse bias was minimized by the use of adequate weighting factors in the analyses. In addition, calculation of influenza vaccination coverage was based on self-reported data and might therefore be subject to recall bias, which could result in over- or underestimations of coverage. However, several studies have shown that self-reported influenza vaccination status has an adequate degree of validity.21,22 Moreover, data collection took place near the end of the vaccination campaign, suggesting that individuals were able to remember their vaccine status. Finally, as in most surveys, we cannot exclude the potential of socially desirable responses. However, the fact that the interviews were conducted by a professional polling firm should have minimized this bias. CONCLUSIONS Our results indicate that seasonal influenza vaccine uptake among at-risk groups targeted by the publicly funded program in Quebec remains well below the goal of 80% coverage rate, but did return to the level reached before the influenza A(H1N1) pandemic. In fact, seasonal influenza vaccine uptake rates in at-risk groups have remained relatively stable over time, despite highly accessible vaccination services and efforts on the part of public health authorities to promote the use of this vaccine. This highlights the need to develop more effective communication strategies to educate and inform individuals about seasonal influenza vaccination. Health communication messages should address the most common misconceptions about the need for safety and efficacy of the seasonal influenza vaccine. Because the role of health care workers is crucial for the success of seasonal influenza vaccination programs, particular efforts should be made to promote vaccine uptake among this group. References 1. Ministère de la Santé et des Services sociaux. Programme national de santé publique - Mise à jour 2008. Quebec, Canada: Ministère de la Santé et des Services Sociaux; 2008. p. 100.
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2. Guay M, Côté L, Boulianne N, Landry M, Markowski F. Enquête québécoise sur les couvertures vaccinales contre l’influenza et le pneumocoque. Québec, Canada: Institut de la statistique du Québec; 2008. p. 57. 3. Dubé E, Kiely M, Defay F, Guay M, Boulianne N, Sauvageau C, et al. Enquête québécoise sur la vaccination contre la grippe A(H1N1), la grippe saisonnière et le pneumocoque. Québec, Canada: Institut national de santé publique du Québec et ministère de la Santé et des Services sociaux; 2011. p. 73. 4. Dubé E, Defay F, Kiely M, Guay M, Boulianne N, Sauvageau C, et al. Enquête québécoise sur la vaccination contre la grippe saisonnière, le pneumocoque et la rougeole en 2012. Québec, Canada: Institut national de santé publique du Québec et ministère de la Santé et des Services sociaux; 2013. p. 137. 5. Environics Research Group. Canadian Adult National Immunization Coverage (NICS) Survey e 2010-Québec. Ottawa, Canada: Ministère de la Santé et des Services sociaux du Québec; 2011. p. 109. 6. Ketterer F, Goffin Y, Boyer P, Freyens A, Sourbes A, Belche J-L, et al. Criteria of the patient’s decision concerning vaccination against influenza AH1N1, in Belgium and France. Presse Med 2013;42:e63-8. 7. Statistiques Canada. Influenza immunization, less than one year ago by sex, by province and territory. Available from: http://www.statcan.gc.ca/ tables-tableaux/sum-som/l01/cst01/health102a-eng.htm. Accessed September 17, 2013. 8. Tacken MA, Jansen B, Mulder J, Visscher S, Heijnen M-L, Campbell SM, et al. Pandemic influenza A(H1N1)pdm09 improves vaccination routine in subsequent years: a cohort study from 2009 to 2011. Vaccine 2013;31:900-5. 9. Guthmann J-P, Bonmarin I, Lévy-Bruhl D. Influenza vaccination coverage one year after the A(H1N1) influenza pandemic, France, 2010-2011. Vaccine 2012; 30:995-7. 10. Bish A, Yardley L, Nicoll A, Michie S. Factors associated with uptake of vaccination against pandemic influenza: a systematic review. Vaccine 2011;29: 6472-84. 11. Kohlhammer Y, Schnoor M, Schwartz M, Raspe H, Schafer T. Determinants of influenza and pneumococcal vaccination in elderly people: a systematic review. Public Health 2007;121:742-51. 12. Ward L, Draper J. A review of the factors involved in older people’s decision making with regard to influenza vaccination: a literature review. J Clin Nurs 2008;17:5-16. 13. Nagata JM, Hernández-Ramos I, Kurup A, Albrecht D, Vivas-Torrealba C, Franco-Parades C. Social determinants of health and seasonal influenza vaccination in adults 65 years: a systematic review of qualitative and quantitative data. BMC Public Health 2013;13:388. 14. Brien S, Kwong JC, Buckeridge DL. The determinants of 2009 pandemic A/H1N1 influenza vaccination: a systematic review. Vaccine 2012;30:1255-64. 15. Zhang J, While AE, Norman IJ. Knowledge and attitudes regarding influenza vaccination among nurses: a research review. Vaccine 2010;28:7207-14. 16. Hollmeyer HG, Hayden F, Poland G, Buchholz U. Influenza vaccination of health care workers in hospitalsda review of studies on attitudes and predictors. Vaccine 2009;27:3935-44. 17. Riphagen-Dalhuisen J, Gefenaite G, Hak E. Predictors of seasonal influenza vaccination among healthcare workers in hospitals: a descriptive meta-analysis. Occup Environ Med 2012;69:230-5. 18. Edwards P. ParticipACTION: the mouse that roared. A marketing and health communication success story (supplement). Can J Public Health 2004;95(Suppl 2):S1-44. 19. Fabry P, Gagneur A, Pasquier JC. Determinants of A(H1N1) vaccination: crosssectional study in a population of pregnant women in Quebec. Vaccine 2011; 29:1824-9. 20. Ashbaugh A, Herbert CF, Saimon E, Azoulay N, Olivera-Figueroa L, Brunet A. The decision to vaccinate or not during the H1N1 pandemic: selecting the lesser of two evils? PLoS One 2013;8:e58852. 21. Mangtani P, Shah A, Roberts J. Validation of influenza and pneumococcal vaccine status in adults based on self-report. Epidemiol Infect 2007;135: 139-43. 22. Kroneman MW, van Essen GA, Taken MA, Paget WJ, Verheij R. Does a population survey provide reliable influenza vaccine uptake rates among high-risk groups? A case-study of The Netherlands. Vaccine 2004;22:2163-70.
Contents lists available at ScienceDirect
American Journal of Infection Control
American Journal of Infection Control
journal homepage: www.ajicjournal.org
Major article
Seasonal influenza vaccination uptake in Quebec, Canada, 2 years after the influenza A(H1N1) pandemic Eve Dubé PhD a, b, *, Dominique Gagnon MSc a, Marilou Kiely MSc a, Fannie Defay MSc b, Maryse Guay MD, MSc, FRCPC a, c, d, Nicole Boulianne MSc a, b, Chantal Sauvageau MD, MSc, FRCPC a, b, Monique Landry MD e, Bruno Turmel MD e, France Markowski BSc e, Nathalie Hudon MA Comm e a
Institut national de santé publique du Québec, Québec City, Québec, Canada Centre de recherche du CHU de Québec, Québec City, Québec, Canada c Université de Sherbrooke, Sherbrooke, Québec, Canada d Direction de santé publique de Montérégie, Longueuil, Québec, Canada e Ministère de la Santé et des Services sociaux du Québec, Québec City, Québec, Canada b
Key Words: Immunization Vaccination coverage Survey Flu
Background: A decrease in seasonal influenza vaccine uptake was observed after the influenza A(H1N1) pandemic in 2009. The goal of our study was to assess seasonal influenza vaccine uptake in 2011-2012, 2 years after the influenza A(H1N1) pandemic mass immunization campaign and to identify the main reasons for having or not having received the vaccine. Methods: A telephone survey using random-digit dialing methodology was conducted. Case-weights were assigned to adjust for disproportionate sampling and for nonresponse bias. Descriptive statistics were generated for all variables. Results: Seasonal influenza vaccine uptake was 57% among adults aged 60 years, 35% among adults with chronic medical conditions, and 44% among health care workers. The main reasons given for having been vaccinated were to be protected from influenza and a high perceived susceptibility to influenza, whereas low perceived susceptibility to influenza and low perceived severity of influenza were the main reasons for not having been vaccinated. Conclusions: An increase in seasonal influenza vaccine uptake was observed 2 years after the influenza A(H1N1) pandemic. However, vaccine coverage is still below the target level of 80%. More efforts are needed to develop effective strategies to increase seasonal influenza vaccine uptake. Copyright Ó 2014 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.
Annual vaccination is one of the most effective measures for preventing severe outcomes of influenza. The Canadian National Advisory Committee on Immunization recommends influenza vaccination for people at high risk of serious infection as well as for their contacts. In the province of Quebec, at-risk groups targeted by the publicly funded influenza vaccination program are infants aged 6-23 months; adults aged 60 years; individuals aged 2 years with chronic medical conditions (eg, cardiac and pulmonary disorders, diabetes, immune-compromised conditions, renal disease, and asthma); and people such as health care workers who, as part of their work or daily life, have frequent contact with people at * Address correspondence to Eve Dubé, PhD, Institut national de santé publique du Québec, 2400 D’Estimauville, Québec (QC), Canada G1E 7G9. E-mail address: [email protected] (E. Dubé). Conflicts of interest: None to report.
higher risk of complications from infection. Each year, a large-scale influenza vaccination campaign is organized and the vaccine is offered free of charge to targeted groups throughout the province in different settings such as mass-vaccination clinics, long-term facilities, as well as health care institutions. To promote vaccine uptake, public health authorities run a promotional campaign every year during the influenza season. For the 2011-2012 campaign, the slogan used was: “The flu spreads easily. Get vaccinated.” As part of the promotional campaign, the slogan was conveyed through different means such as posters and flyers as well as by television, newspaper, and radio ads. Despite these efforts, influenza vaccination coverage among groups included in the publicly funded program remains below the target level of 80%.1 For instance, during the 2007-2008 campaign, approximately 58% of Quebecers aged 60 years received the influenza vaccine.2 During the 2010 vaccination
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campaign (January-April), just following the mass vaccination campaign for pandemic influenza A(H1N1), the proportion of vaccinated people aged 60 years decreased to 36%. The seasonal influenza vaccine uptake during 2010 was also very low in other high-risk groups, with fewer than one-third of individuals with chronic medical conditions (32%) and of health care workers (21%) reporting having received the vaccine.3 However, influenza A(H1N1) pandemic influenza vaccine uptake was high, with 77% of individuals aged 65 years, 76% of adults with chronic medical conditions, and 85% of health care workers being vaccinated against pandemic influenza.3 The main objective of our study was to document if the decrease in seasonal influenza coverage rates observed for the 2010 campaign has persisted over time. METHODS Results presented here are drawn from the 2012 Quebec study on vaccination against seasonal influenza, pneumococcal infections, and measles (l’Enquête québécoise sur la vaccination contre la grippe saisonnière, le pneumocoque et la rougeole [EQVGPR], 2012),4 a cross-sectional study conducted by telephone among a representative sample of Quebec households. We focus only on the EQVGPR section related to influenza vaccination for which eligible respondents were aged 60 years or older, were adults with a chronic medical condition (eg, asthma, other chronic pulmonary disease, cardiac problems, diabetes, cirrhosis of the liver, chronic kidney disease, cancer, or other immune system problem), or were health care workers (eg, an employee or volunteer in a health care environment such as a hospital or a clinic). To measure vaccination coverage, validated questions from preceding surveys were used.2,3,5 Reasons for having or not having received the influenza vaccine and for not intending to receive it in the following influenza season (2012-2013) were collected using open-ended questions. Different questions were asked to assess the awareness of promotional messages regarding seasonal influenza (eg, having heard the message, remembering the message, or if the message influenced the respondent’s opinion or behavior). Standard sociodemographic variables were also collected. The survey instrument is available from the authors upon request. The sample was constituted using random-digit dialing methodology and was stratified to ensure representativeness of 16 out of 18 sociosanitary regions in Quebec (2 northern regions were excluded). A professional research and polling firm handled recruitment and data collection. The computer-assisted telephone interviews were carried out from March-May 2012. Interviews were conducted in French or in English according the participant’s preferred language. The EQVGPR study was approved by the Research Ethics Board of the Centre hospitalier universitaire de Québec (project No. C12-02-181). Expansion weights were assigned to ensure that the results were representative of the target population by adjusting for disproportionate sampling and nonresponse bias. Weighting was applied to each respondent in the sample based on sociodemographic characteristics drawn from the answers of respondents who agreed to participate but who were not eligible because of quotas already attained as well as from census data (detailed methodology for the weighting can be found elsewhere).4 Descriptive statistics were generated for all variables. For each estimate, 95% confidence intervals (CIs) were calculated. Comparison between vaccine uptake and other sociodemographic variables were done using c2 or Fisher exact tests as appropriate. For univariate analysis, a probability level of P < .05 was considered
statistically significant. The exact verbatim of the open-ended questions was transcribed by the interviewers and submitted to content analysis. Statistical analyses were performed using SAS version 9.3 (SAS Institute Inc, Cary, NC), whereas content analysis was first done using word processing software and then imported into SAS version 9.3 software. RESULTS The response rate for the EQVGPR was 48% and a total of 2,516 individuals aged 60 years, 2,289 individuals with chronic medical conditions aged 18-59 years, and 754 health care workers aged 1859 years participated in the study. A subgroup of respondents who completed the questionnaire pertaining to seasonal influenza vaccination and their characteristics are shown in Table 1. Among adults with chronic medical conditions, asthma was reported mainly by adults aged 18-49 years (69.5% vs 37.3% for adults aged 50-59 years), whereas cardiac disease and diabetes were reported more frequently by adults aged 50 to 59 years (25.7% and 26.1% for adults aged 50-59 years vs 5.6% and 13.2% for adults aged 18-49 years). Health care workers were mostly managers, administrative personnel, and support staff (24.1%). Other health professionals such as nutritionists, dentists, psychologists, occupational therapists, physiotherapists, health technicians, specialized educators, and social workers constituted 21.4% of the sample of health care workers. Seasonal influenza vaccination coverage rates For the 2011-2012 campaign, 56.6% of individuals aged 60 years reported having received the vaccine (95% CI, 54%-59%). Vaccine uptake was higher among individuals aged 65 years than among those aged 60-64 years (61.3% vs 44.9%; P < .0001). Seasonal influenza vaccine uptake was higher among respondents aged 6069 years with chronic conditions compared with others without chronic conditions (ages 60-64 years 56% vs 38%; ages 65-69 years 60% vs 50%; P < .05). Having chronic conditions did not influence influenza vaccine uptake among persons aged 70 years (68% vs 61%; P ¼ .08). No difference between sexes was found in vaccine uptake among people aged 60 years. Fewer than one-third (29.9%; 95% CI, 26.2%-34.7%) of adults aged 18-59 years with chronic medical conditions had received the influenza vaccine for the same period. A difference in vaccine uptake was also found between younger and older people with chronic medical conditions (40% for adults aged 50-59 years vs 25% for adults aged 18-49 years; P < .001). Within the 18-49 age group with chronic medical conditions, more women were vaccinated than men (29.2% vs 19.3%; P ¼ .05). No statistically significant differences were found in vaccine uptake among individuals having different types of chronic medical conditions. Seasonal influenza vaccine uptake was higher among individuals aged 60-69 years with chronic medical conditions compared with others without chronic conditions (P < .05). However, having a chronic medical condition did not influence influenza vaccine uptake among individuals aged 70 years (P ¼ .08). Finally, fewer than half of health care workers reported having received the influenza vaccine during the 2011-2012 campaign (43.5%; 95% CI, 37.4%-49.6%). By type of work, vaccine uptake was 32.4% for managers, administrative personnel, and support staff (95% CI, 21.6%-43.2%); 61.6% for nurses (95% CI, 49.5%-73.6%); 50.5% for patient care attendants (95% CI, 33.5%-37.5%), and 39.8% for other health professionals (95% CI, 27.0%-52.6%). Physicians were the health care workers with the highest vaccine uptake (89.2%; 95% CI, 75.3%-100%). In addition, vaccine uptake was significantly
E. Dubé et al. / American Journal of Infection Control 42 (2014) e55-e59 Table 1 Sociodemographic characteristics of study respondents*
Characteristic Individuals aged 60 y (n ¼ 2,516) Age 60-64 y 65 y Sex Male Female People living with CMCy 60-64 y 65 y Individuals aged 18-59 y with CMC (n ¼ 1,145) Age 18-49 y 50-59 y Sex Male Female CMC Asthma 18-49 y 50-59 y Chronic obstructive pulmonary diseasez 18-49 y 50-59 y Cardiac diseasesx 18-49 y 50-59 y Diabetes 18-49 y 50-59 y Cirrhosis of the liver 18-49 50-59 y Chronic kidney disease 18-49 y 50-59 y Cancer or other immune system problem 18-49 y 50-59 Health care workers aged 18-59 y (n ¼ 454) Age 18-49 y 50-59 y Sex Male Female Type of work Physician Nurse Patient attendantjj Other health professional{ Manager, administrative personnel, or support staff Volunteer Other Don’t know e refusal
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Main reasons for having or not having received the seasonal influenza vaccine
Unweighted n
Weighted %
795 1,721
28.5 71.5
978 1,538
45.3 54.7
298 846
39.1 49.2
595 550
66.3 33.7
455 690
47.5 52.5
408 209
69.5 37.3
55 78
8.9 13.1
59 121
5.6 25.7
64 147
13.2 26.1
5 5
1.2 1.0
17 22
2.9 4.1
82 126
12.0 20.9
224 230
72.7 27.3
77 377
20.1 79.9
20 104 66 84 119
3.9 19.1 16.4 21.4 24.1
<20 43 <20
2.4 12.0 0.8
CMC, chronic medical conditions. *Unweighted numbers represent the exact number of respondents in each group. Weighted numbers represent the proportion of these respondents in the overall sample after adjustment for disproportionate sampling and nonresponse bias. y Respondent could have indicated >1 disease. z Includes emphysema, chronic bronchitis, and cystic fibrosis. x Includes angina, high blood pressure, heart failure, and heart attack. jj Includes caregivers/home care workers. { Includes nutritionists, dentists, psychologists, occupational therapists, physiotherapists, health technicians, specialized educators, and social workers.
higher among health care workers having frequent contact with patients (eg, nurses, physicians, patient care attendants, and other health professionals) when compared with those without frequent contact (eg, managers, administrative personnel, and support staff) (53% vs 32%, respectively; P ¼ .0019).
Table 2 presents the main reasons for having received or not received the influenza vaccine during the 2011-2012 campaign. The 3 most frequent reasons for being vaccinated against influenza among individuals aged 60 years were self-protection, a generally positive attitude regarding vaccination, and social responsibility (eg, thinking vaccination is a duty) as well as considering oneself an at-risk person due to type of work, presence of medical conditions, or travel considerations. Considering oneself an at-risk person and self-protection were the main reasons for vaccination reported by individuals aged 18-59 years with chronic medical conditions as well as by health care workers. Among all groups, the main reasons for not having received the seasonal influenza vaccine were low perceived susceptibility to influenza or low perceived severity of influenza, lack of interest, time, or information, and fear of side effects. Of note is the fact that 10.4% of individuals aged 60 years (95% CI, 8.0%-12.9%), 7.3% of individuals with chronic medical conditions (95% CI, 4.3%-10.3%), and 12% of health care workers (95% CI, 4.9%-19.2%) mentioned not having received the influenza vaccine because of a generally negative attitude toward medication and vaccines. Intention to receive the seasonal influenza vaccine during the next vaccination campaign Sixty-two percent of individuals aged 60 years, 41% of individuals with chronic medical conditions, and 54% of health care workers said they intended to be vaccinated during the next season. Among the 3 groups, the main reason for not intending to be vaccinated was a low perceived susceptibility to influenza or a low perceived severity of the disease (data not presented). The intention to be vaccinated during the next season was higher among people who had received the vaccine during the 2011-2012 campaign compared with those who did not. Awareness of the seasonal influenza vaccine promotional campaign Fifty-seven percent of individuals aged 60 years (95% CI, 54.4%59.2%), 50.4% of adults with chronic medical conditions (95% CI, 46.2%-54.6%), and 63% of health care workers (95% CI, 56.6%-68.8%) remembered having seen or heard the slogan of the promotional campaign. However, the majority of individuals in all groups reported that the slogan had no influence on their decision to get vaccinated (78% of adults aged 60 years [95% CI, 75.1%-80.5], 81% of adults with chronic medical conditions [95% CI, 76.6%-85.3%], and 79% of health care workers [95% CI, 71.9%-85.9%]). A minority mentioned that the slogan had a negative influence on their decision to get vaccinated against influenza (4% of adults aged 60 years [95% CI, 2.7%-5.0%], 2% of adults with chronic medical conditions [95% CI, 0.8%-3.7%], and 1% of health care workers [95% CI, 0.2%-2.8%]). There was no statistically significant difference in seasonal vaccine uptake between individuals who reported having seen or heard the slogan and those who did not. However, vaccine uptake was higher among people who mentioned that the slogan had a positive influence on their decision to get vaccinated. Indeed, the vaccine uptake among individuals aged 60 years who stated that the slogan had a positive influence on their decision was 81% compared with 50% for those who reported negative or no influence (P < .0001). The findings were similar for adults with chronic medical conditions (vaccine uptake was 61% among individuals who reported positive influence of the slogan vs 27% for those who reported negative or no influence; P < .0001) and for health care workers (72% vs 41%; P ¼ .0017).
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Table 2 Main reasons for having received or not received the seasonal influenza vaccine during the 2011-2012 influenza vaccination campaign*
Reason For being vaccinated Protection of oneself General positive attitude about vaccination/social responsibility Considering oneself at risk Recommendation to receive the vaccine Protection of others For not having received vaccination Low perceived susceptibility to influenza or severity of the infection Lack of interest/lack of time/lack of information Against medication and vaccines Fear of side effects Low perception of vaccine efficacy Doubts regarding vaccine efficacy
60 y % (95% CI)
18-59 years with CMC % (95% CI)
Health professionals % (95% CI)
50.0 20.7 13.8 10.0 4.0
(46.7-53.3) (18.0-23.3) (11.7-16.0) (8.0-12.0) (2.9-5.2)
28.6 5.2 46.9 5.1 11.6
(21.9-35.3) (1.8-8.6) (39.8-54.1) (2.6-7.7) (7.3-16.0)
22.9 9.7 53.4 1.3 10.7
(16.0-29.8) (3.0-16.3) (44.7-62.0) (0.0-2.7) (4.7-15.7)
46.4 16.9 10.4 10.0 4.8 4.0
(42.8-50.1) (14.1-19.8) (8.0-12.9) (7.8-12.1) (3.1-6.5) (2.6-5.4)
42.0 20.7 7.3 11.1 4.9 4.3
(36.9-47.2) (16.5-25.0) (4.3-10.3) (7.6-14.6) (2.6-7.2) (2.4-6.1)
27.7 25.0 12.0 17.1 6.8 4.8
(19.8-35.6) (16.3-33.6) (4.9-19.2) (9.3-24.9) (2.9-10.6) (1.6-8.1)
CMC, chronic medical conditions. *Reasons mentioned by <4% for >1 group are not shown.
DISCUSSION Results of our study indicate that influenza vaccination coverage for targeted groups is still below the objective of 80%, ranging from 29.9% for adults with chronic medical conditions to 43.5% of health care workers and 56.6% for individuals aged 60 years. However, with vaccine uptake comparable to the 2007-2008 estimates,2 our results show that the decrease observed in seasonal influenza vaccination coverage following the mass vaccination campaign for influenza A(H1N1) pandemic influenza was not maintained over time. The particular context of the Quebec 2010 seasonal influenza vaccination campaign (which was carried out January-April only, just after the mass vaccination campaign against pandemic influenza) may be an explanation for the low vaccine coverage rates observed. The unwillingness of individuals to receive 2 vaccines against influenza during one season has been observed elsewhere.6 Indeed, a similar patternddiminution for the 2009-2010 campaign and a return to prepandemic vaccination coverage rates for the 2011-2012 campaigndwas also observed in other Canadian provinces and territories.7 Results of 2 large studies8,9 also suggest that the influenza A(H1N1) pandemic vaccination campaign did not negatively affect subsequent seasonal influenza vaccination rates. In fact, except for the 2010 campaign, seasonal influenza coverage rates are relatively stable over time in Quebec.2 Results of our study also show that the main reasons for not being vaccinated were related to a low perceived threat of influenza. On the other hand, people who received the vaccine shared motives of self-protection and protection of relatives and other atrisk persons as well as a high perceived susceptibility to influenza. In addition, intention to be vaccinated during the next campaign seems to be strongly correlated with vaccine status at the time of the survey. Reasons to accept or refuse the vaccine that we identified are congruent with results of most studies.10-13 For instance, past vaccination behavior has been identified as a determinant of vaccine uptake in numerous studies.10,12 In addition, in a systematic review of the determinants of influenza and pneumococcal vaccination in elderly populations, Kohlhammer et al11 indicated that the most common reasons for not having received influenza vaccination were the absence of risk perception, disbelief in the efficacy of vaccination, and the fear of side effects. This highlights the important role health care workers play in addressing patients’ doubts about the safety and effectiveness of the vaccine. Providers’ recommendations are an important determinant of influenza vaccine uptake.10,11,14 Findings of a review on determinants of nurses’ practices regarding influenza vaccination indicate that higher knowledge and positive attitudes toward
influenza vaccination were positively associated with vaccination coverage among nurses. There was also an association between nurses’ vaccination status and their reported promotion of vaccination with their patients.15 In this regard, the relatively low vaccine uptake among health care workers shown in our study is worrying, especially given the fact that free vaccines are available at the workplace and that strong recommendations to be vaccinated are made each year by professional associations and public health authorities. In addition, although many studies have shown that social responsibility is an important driver of health professionals’ decision to be vaccinated against influenza,16,17 most health care workers surveyed in our study indicated that they received the vaccine to protect themselves or because they considered themselves to be at risk for infection. This could be explained, at least partially, by the fact that we asked for only the main reason behind vaccine decisions. Awareness of promotional messages is a parameter frequently used to evaluate health-promotion campaigns.18 Results of our study indicate a mixed effect of the promotional campaign for seasonal influenza vaccination. Despite the fact that the majority of respondents did remember having seen or heard the slogan, no statistically significant difference was found in vaccine uptake between individuals who remembered the slogan and those who did not. Studies have shown that the type of source of vaccination information sought by patients is associated with vaccine decision making.14,19,20 For instance, results of a study conducted by Ashbaugh et al20 showed that individuals who did not intend to be vaccinated against pandemic influenza were more likely to report that the Internet was an influential source of information compared with government sources. Indeed, building trust in public health authorities’ recommendations is important. Government agencies need to be more proactive in providing evidence-based information, especially to at-risk groups. Efforts should also be made to increase the visibility of official Web sites and to be more present on social networking Web sites.20 Strengths and limitations Because Quebec has no central immunization registry, information on vaccination coverage can only be obtained through surveys. Monitoring vaccination coverage is essential in evaluating the capacity of the influenza vaccination program to attain its objectives. Moreover, our methodology allowed us to obtain important data on the reasons behind vaccine decision making that could not be recorded in an immunization registry. Indeed, one of the major strengths of our study is the wealth of data collected, both the large sample size, which includes all target groups, and in the
E. Dubé et al. / American Journal of Infection Control 42 (2014) e55-e59
type of data, which includes reasons behind vaccine decision making. Other strengths of our study were the use of random-digit dialing methodology for data collection and the use of case-weights to adjust for disproportionate sampling and for nonresponse bias. For these reasons, our estimates of influenza vaccine coverage are reliable and representative of the Quebec population. Our study has some limitations that need to be acknowledged. This study is descriptive. Although we looked at potential differences in vaccine uptake between respondents with different sociodemographic characteristics, no multivariate analysis was performed. The response rate for the entire survey was not optimal (48%), but remains satisfactory for a telephone survey.5 Nonresponse bias was minimized by the use of adequate weighting factors in the analyses. In addition, calculation of influenza vaccination coverage was based on self-reported data and might therefore be subject to recall bias, which could result in over- or underestimations of coverage. However, several studies have shown that self-reported influenza vaccination status has an adequate degree of validity.21,22 Moreover, data collection took place near the end of the vaccination campaign, suggesting that individuals were able to remember their vaccine status. Finally, as in most surveys, we cannot exclude the potential of socially desirable responses. However, the fact that the interviews were conducted by a professional polling firm should have minimized this bias. CONCLUSIONS Our results indicate that seasonal influenza vaccine uptake among at-risk groups targeted by the publicly funded program in Quebec remains well below the goal of 80% coverage rate, but did return to the level reached before the influenza A(H1N1) pandemic. In fact, seasonal influenza vaccine uptake rates in at-risk groups have remained relatively stable over time, despite highly accessible vaccination services and efforts on the part of public health authorities to promote the use of this vaccine. This highlights the need to develop more effective communication strategies to educate and inform individuals about seasonal influenza vaccination. Health communication messages should address the most common misconceptions about the need for safety and efficacy of the seasonal influenza vaccine. Because the role of health care workers is crucial for the success of seasonal influenza vaccination programs, particular efforts should be made to promote vaccine uptake among this group. References 1. Ministère de la Santé et des Services sociaux. Programme national de santé publique - Mise à jour 2008. Quebec, Canada: Ministère de la Santé et des Services Sociaux; 2008. p. 100.
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2. Guay M, Côté L, Boulianne N, Landry M, Markowski F. Enquête québécoise sur les couvertures vaccinales contre l’influenza et le pneumocoque. Québec, Canada: Institut de la statistique du Québec; 2008. p. 57. 3. Dubé E, Kiely M, Defay F, Guay M, Boulianne N, Sauvageau C, et al. Enquête québécoise sur la vaccination contre la grippe A(H1N1), la grippe saisonnière et le pneumocoque. Québec, Canada: Institut national de santé publique du Québec et ministère de la Santé et des Services sociaux; 2011. p. 73. 4. Dubé E, Defay F, Kiely M, Guay M, Boulianne N, Sauvageau C, et al. Enquête québécoise sur la vaccination contre la grippe saisonnière, le pneumocoque et la rougeole en 2012. Québec, Canada: Institut national de santé publique du Québec et ministère de la Santé et des Services sociaux; 2013. p. 137. 5. Environics Research Group. Canadian Adult National Immunization Coverage (NICS) Survey e 2010-Québec. Ottawa, Canada: Ministère de la Santé et des Services sociaux du Québec; 2011. p. 109. 6. Ketterer F, Goffin Y, Boyer P, Freyens A, Sourbes A, Belche J-L, et al. Criteria of the patient’s decision concerning vaccination against influenza AH1N1, in Belgium and France. Presse Med 2013;42:e63-8. 7. Statistiques Canada. Influenza immunization, less than one year ago by sex, by province and territory. Available from: http://www.statcan.gc.ca/ tables-tableaux/sum-som/l01/cst01/health102a-eng.htm. Accessed September 17, 2013. 8. Tacken MA, Jansen B, Mulder J, Visscher S, Heijnen M-L, Campbell SM, et al. Pandemic influenza A(H1N1)pdm09 improves vaccination routine in subsequent years: a cohort study from 2009 to 2011. Vaccine 2013;31:900-5. 9. Guthmann J-P, Bonmarin I, Lévy-Bruhl D. Influenza vaccination coverage one year after the A(H1N1) influenza pandemic, France, 2010-2011. Vaccine 2012; 30:995-7. 10. Bish A, Yardley L, Nicoll A, Michie S. Factors associated with uptake of vaccination against pandemic influenza: a systematic review. Vaccine 2011;29: 6472-84. 11. Kohlhammer Y, Schnoor M, Schwartz M, Raspe H, Schafer T. Determinants of influenza and pneumococcal vaccination in elderly people: a systematic review. Public Health 2007;121:742-51. 12. Ward L, Draper J. A review of the factors involved in older people’s decision making with regard to influenza vaccination: a literature review. J Clin Nurs 2008;17:5-16. 13. Nagata JM, Hernández-Ramos I, Kurup A, Albrecht D, Vivas-Torrealba C, Franco-Parades C. Social determinants of health and seasonal influenza vaccination in adults 65 years: a systematic review of qualitative and quantitative data. BMC Public Health 2013;13:388. 14. Brien S, Kwong JC, Buckeridge DL. The determinants of 2009 pandemic A/H1N1 influenza vaccination: a systematic review. Vaccine 2012;30:1255-64. 15. Zhang J, While AE, Norman IJ. Knowledge and attitudes regarding influenza vaccination among nurses: a research review. Vaccine 2010;28:7207-14. 16. Hollmeyer HG, Hayden F, Poland G, Buchholz U. Influenza vaccination of health care workers in hospitalsda review of studies on attitudes and predictors. Vaccine 2009;27:3935-44. 17. Riphagen-Dalhuisen J, Gefenaite G, Hak E. Predictors of seasonal influenza vaccination among healthcare workers in hospitals: a descriptive meta-analysis. Occup Environ Med 2012;69:230-5. 18. Edwards P. ParticipACTION: the mouse that roared. A marketing and health communication success story (supplement). Can J Public Health 2004;95(Suppl 2):S1-44. 19. Fabry P, Gagneur A, Pasquier JC. Determinants of A(H1N1) vaccination: crosssectional study in a population of pregnant women in Quebec. Vaccine 2011; 29:1824-9. 20. Ashbaugh A, Herbert CF, Saimon E, Azoulay N, Olivera-Figueroa L, Brunet A. The decision to vaccinate or not during the H1N1 pandemic: selecting the lesser of two evils? PLoS One 2013;8:e58852. 21. Mangtani P, Shah A, Roberts J. Validation of influenza and pneumococcal vaccine status in adults based on self-report. Epidemiol Infect 2007;135: 139-43. 22. Kroneman MW, van Essen GA, Taken MA, Paget WJ, Verheij R. Does a population survey provide reliable influenza vaccine uptake rates among high-risk groups? A case-study of The Netherlands. Vaccine 2004;22:2163-70.