https://orcid.org/0000-0002-7082-2224
ABSTRACT
Objectives: Vaccine hesitancy is a global phenomenon that needs to be measured and addressed. This study aimed to identify the determinants of vaccine hesitancy among a large regional population.
Methods: A structured telephone survey was administered to a random digit sample in Quebec’s Eastern Townships region. In addition to socioeconomic information, respondents were asked questions on several health topics such as knowledge and beliefs about immunization, medical consultations, health status, and life habits. Data were weighted according to age, sex, and territories. Statistically significant variables in the univariate analysis were introduced into a multivariate logistic regression model to determine independent factors for vaccine hesitancy (adjusted odds ratios [aOR] and 95% confidence intervals).
Results: A total of 8,737 interviews were conducted (participation rate 48.3%). Among all respondents, 32.2% were vaccine-hesitant. Several beliefs were significantly associated with vaccine hesitancy: belief that children receive too many vaccines (aOR = 2.72; 2.32–3.18), belief that a healthy lifestyle can eliminate the need for vaccination (aOR = 2.48; 2.09–2.93), and belief that the use of alternative medicine practices can eliminate the need for vaccination (aOR = 1.39; 1.16–1.68). Other determinants associated with vaccine hesitancy were having consulted a massage therapist (aOR = 2.34; 1.46–3.75), not being vaccinated against influenza (aOR = 1.80; 1.49–2.16), having a low (<$30,000) (aOR = 1.58; 1.24–2.02) or moderate ($30,000–$79,000) (aOR = 1.37; 1.12–1.67) household income, distrust in public health authorities (aOR = 1.40; 1.21–1.63), perceived insufficient knowledge about immunization (aOR = 1.26; 1.04–1.51), and smoking (aOR = 1.22; 1.01–1.47).
Conclusions: Many determinants are related to vaccine hesitancy. These determinants should be taken into account when health professionals engage with vaccine-hesitant individuals.
Introduction
Several vaccine-preventable diseases (VPD) were eliminated or controlled with vaccination. However, over the last decade, clusters of under-immunized individuals have led to community outbreaks by increasing transmission of VPD, Citation1 as observed with measles outbreaks in the USA, Canada, and Europe.Citation1–Citation4 This phenomenon, called “vaccine hesitancy”, is a growing issue that needs to be measured and addressed, according to the World Health Organization.Citation5 Vaccine hesitancy refers to delays in acceptance or refusal of vaccination despite the availability of vaccination services.Citation6 Although vaccine hesitancy is a global issue, it is considered context specific, i.e., it can vary across time, from one location to another, and according to the vaccine in question.Citation6
To avoid outbreaks of VPD, high vaccine coverage needs to be reached and maintained. In Quebec (Canada), all vaccines recommended by the provincial immunization program are provided free of charge in public health clinics, hospitals, and physicians’ offices.Citation7 Unfortunately, only 71% of 2-y-olds are fully immunized against VPD (85% if excluding rotavirus vaccine) in Quebec.Citation7 An increasing number of individuals refusing or delaying vaccination for their children have been observed over the last few years.Citation1,Citation8,Citation9 Among the general Quebec population, 31% of the adults ≥60 y, 44% of the adults <60 y with a chronic condition, and 55% of the health-care providers reported some hesitation to receive one or several vaccines for themselves.Citation10 In the same study, 37% of the parents of children aged between 2 months and 17 y reported having hesitated to vaccinate their child.Citation10 Vaccine-hesitant individuals are concerned about the need for and the safety of vaccines.Citation11,Citation12 Trying to convince vaccine-hesitant individuals by giving them a lot of facts and information generally backfires and makes them even more hesitant.Citation13 The need for effective strategies to tackle vaccine hesitancy is, therefore, required.Citation14,Citation15
Since vaccine hesitancy varies across settings, local assessments are needed to develop appropriate strategies.Citation16 To our knowledge, only a few studies have assessed vaccine hesitancy and its determinants on a population basis.Citation17 This study aimed to identify the determinants of vaccine hesitancy among a large regional population.
Results
A total of 8,737 individuals completed the questionnaire, for a participation rate of 48.3%. Among these, 7,205 (82.5%), 820 (9.4%), and 712 (8.1%) answered the questionnaire via a phone, the Internet, and a cellphone, respectively. Participants were aged 18–95 y old, with 59.5% of the respondents aged between 30 and 64 (). More than half of the respondents (55.4%) lived in the region’s main city, Sherbrooke, and most of them (93.1%) spoke French at home.
Table 1. Demographic and socioeconomic characteristics of respondents according to vaccine hesitancy, Eastern Townships, 2014.
Among all respondents, 32.2% were identified as vaccine-hesitant, with 13.3% and 18.9% identified as totally and somewhat vaccine-hesitant, respectively.
Compared to non-vaccine-hesitant respondents, vaccine-hesitant people were less likely to reside in the region’s main metropolitan area (51.0% vs. 57.5%, p < 0.001) and lived with a partner (57.0% vs. 63.5%, p < 0.001). In the vaccine-hesitant group, people were more likely to have a lower education level (42.8% vs. 29.6%, p < 0.001), to have a lower household income (35.1% vs. 23.2%, p < 0.001), and to speak French at home (95.9% vs. 91.7%, p < 0.001).
Several variables pertaining to immunization were independently associated with vaccine hesitancy: belief that children receive too many vaccines (adjusted odds ratios [aOR] = 2.72; 2.32–3.18), belief that a healthy lifestyle can eliminate the need for vaccination (aOR = 2.48; 2.09–2.93), belief that the use of alternative medicine practices can eliminate the need for vaccination (aOR = 1.39; 1.16–1.68), and perceived insufficient knowledge about immunization (aOR = 1.26; 1.04–1.51) (). As for specific Health Belief Model (HBM) items, perceived vulnerability, vaccine benefits (flu vaccine can cause the flu and does not prevent flu transmission to family members and relatives), and one item of vaccine risks presented significant aOR.
Table 2. Determinants of vaccine hesitancy, Eastern Townships, 2014 (Part 1 – HBM items).
Some health-care professional consultation habits were significantly linked to vaccine hesitancy, such as having consulted a massage therapist (aOR = 2.34; 1.46–3.75) or not having consulted a medical specialist over the last 12 months (aOR = 1.26; 1.08–1.48) (). Those who did not vaccinate against influenza in the previous (2013–2014) season were nearly two times as likely to be vaccine hesitant than those who were vaccinated against influenza in the previous season (aOR = 1.80; 1.49–2.16). Smoking cigarettes was also independently associated with vaccine hesitancy (aOR = 1.22; 1.01–1.47). Participants who did not agree with the fluoridation of drinking water were also significantly more vaccine-hesitant compared to participants who did (aOR = 1.40; 1.21–1.63).
Table 3. Determinants of vaccine hesitancy, Easter Townships, 2014 (Part 2 – Health-care consultations and life habits).
Some demographic and socioeconomic characteristics were also identified as independent determinants of vaccine hesitancy: having a low (<$30,000) (aOR = 1.58; 1.24–2.02) or moderate ($30,000–$79,000) (aOR = 1.37; 1.12–1.67) household income, speaking French at home (aOR = 1.48; 1.09–2.02), and not living with a child less than 5 y of age (aOR = 1.26; 1.02–1.57) ().
Table 4. Determinants of vaccine hesitancy, Eastern Townships, 2014 (Part 3 – Demographic and socioeconomic variables).
Discussion
This study aimed to identify determinants of vaccine hesitancy among a large sample of the population residing in the Eastern Townships region because many health practitioners in the region were concerned about vaccine hesitancy. No regional data regarding vaccine hesitancy were available, but a previous study showed that this phenomenon existed in the Eastern Townships.Citation18 This region contains some anti-vaccination groups explaining why the proportion of children who received no vaccine is slightly higher in the Eastern Townships (4–5%) compared to the rest of the Province of Quebec (1%).Citation19 Population-based measurement of the level of vaccine hesitancy and its determinants is important in order to implement specific promotion and communication strategies among specific target subgroupsCitation16 and support training of immunization providers with strategies such as motivational interviewing. The present study was conducted among a large sample of residents aged between 18 and 95 y and not only among parents of young children as was the case in prior studies.Citation20–Citation22
According to our findings, 32% of our population were vaccine-hesitant according to the general question that was asked. This proportion is consistent with the findings from other studies that also reported an approximate rate of one-in-three vaccine-hesitant individuals among their study population.Citation10,Citation17,Citation20–Citation22
Several items based on the HBM were significantly associated with vaccine hesitancy. For practical reasons, HBM items were related to influenza vaccination because this vaccine is largely recommended and has received many criticisms. Respondents that considered themselves not at risk of catching the flu and believed that the influenza vaccine could cause the flu or side effects were significantly more likely to be vaccine-hesitant after adjusting for all variables. In Canada and in the USA, a lack of belief in disease susceptibility and severity was strongly associated with partial immunization.Citation11,Citation23 Several studies also found an independent link between parental concerns about vaccine safety and under-immunization.Citation11,Citation17,Citation20,Citation23 “Perceived severity of influenza” was the only component that was not identified in our study as an independent determinant of vaccine hesitancy.
Other determinants strongly associated with vaccine hesitancy were the belief that a healthy lifestyle and alternative medicine practices could eliminate the need for vaccination. Indeed, others found similar results and showed that parents concerned with the utility or the necessity of vaccines were more likely to intend to follow an alternative immunization schedule for their children.Citation20 According to qualitative studies, vaccine-hesitant parents believed they could protect their child’s life from infectious diseases through good nutrition, physical activity, handwashing, high air quality, and limited contact with other children (e.g., by avoiding daycare), rather than through immunization.Citation11,Citation18
Respondents who felt that children receive too many vaccines were also more likely to be vaccine-hesitant, regardless of other confounding variables. Indeed, some vaccine-hesitant individuals may be preoccupied about the number of vaccines perceived to be given too early to their children and during a too short time window.Citation11 In a Canadian study, parents who believed that too many shots were administered at one time were less likely to complete their children’s immunization schedule.Citation23 Moreover, people who feel they had insufficient knowledge about vaccination were more likely to be vaccine-hesitant. Several studies demonstrated the association between the perceived lack of information and negative attitudes about immunization.Citation11,Citation24
Health professional consultation habits were also identified as a vaccine hesitancy determinant. For instance, having consulted a massage therapist was significantly associated with vaccine hesitancy. This result is consistent with the belief that the use of alternative medicine practices can eliminate the need for vaccination, also identified in the study as an independent determinant of vaccine hesitancy. A similar finding was demonstrated in a UK study where parents who chose to delay their children’s vaccination were significantly more likely to have visited a homeopath.Citation25 The use of alternative medicine resources such as chiropractors, naturopaths, and midwives was reported by mothers of under-immunized children in a study conducted in the Eastern Townships region.Citation18 This study also showed a significant association between midwife-assisted birth and an incomplete vaccine status for the child, Citation18 meaning that mothers giving birth with a midwife are usually more vaccine-hesitant and did not give their child all the recommended vaccines.
We also found that smoking is significantly linked to vaccine hesitancy. Although it may be a coincidence, this result is supported by other studies who also found a similar association.Citation26,Citation27 This may suggest that vaccine-hesitant individuals appear to have less healthy living habits than non-vaccine-hesitant people. In a US study, smokers were more likely to be unvaccinated against the flu, suggesting that these individuals may be less concerned with health issues such as immunization.Citation26 This association was also found in Turkey where maternal cigarette smoking was significantly linked to an incomplete vaccination status in children <3 y of age.Citation27
Distrust in public health authorities regarding the addition of fluoride in municipal drinking water was identified as an independent determinant of vaccine hesitancy. Parents who refused or delayed their children’s vaccinations are more likely to distrust the government and to be suspicious of the influence of pharmaceutical companies.Citation25,Citation28 They typically present issues of trust in the government’s role in protecting the population from health risks, which could, therefore, apply to a publicly funded government program such as vaccination.
Some socioeconomic factors were also significantly associated with vaccine hesitancy. In many countries, studies demonstrated opposite results: vaccine hesitancy has been associated with both high and low socioeconomic status.Citation29 In our study, respondents with low and moderate household income were significantly more vaccine-hesitant than people having an annual income of ≥$80,000. Although Canadian and US studies showed an association between vaccine hesitancy and both high and low income,Citation12,Citation17,Citation30–Citation35 our result is supported by another study who demonstrated that US mothers with an income <$40,000 were less trusting with regard to vaccines compared to mothers having a higher income.Citation36 The authors suggested that lower socioeconomic status in the USA was linked to a mistrust of the health-care provider, which could, therefore, explain the association between low income and vaccine hesitancy. In our study, trust in the health provider was not assessed, but distrust in public health authorities was identified as a factor increasing vaccine hesitancy. Socioeconomic factors should be further explored in future studies since household income influences vaccine hesitancy even in a setting that benefits from a universal health-care system and where vaccines are publicly funded and available for free. People with low household income may have less access to health care and may thus benefit from fewer recommendations about vaccination.
Speaking French at home was also associated with vaccine hesitancy. This result supports the fact that some cultural factors may be related to vaccine hesitancy.
Finally, not living with a child less than 5 y old was associated with vaccine hesitancy. People living with young children may have more knowledge about vaccines since they likely had to make a decision regarding their children’s vaccination compared to persons not living with young children. This may explain why people not living with young children were more vaccine-hesitant. This last observation is also coherent with the fact that people who reported having insufficient knowledge about vaccination were also more likely to be vaccine-hesitant.
A major strength in this study was the analysis of many variables related to several health-related topics such as physician consultations, perceived health status, life habits, or sociodemographic characteristics. A further strength was the large sample size that made it possible to include many variables in the regression analysis. In studies using telephone surveys, people with no home phone are usually not reached. However, in our study, people with only cell phones and no phone at home were also contacted, which reduced the inherent selection bias generated by this type of study. An online survey was also available to reach more participants.
However, some limits in this study need to be addressed. First, because of the cross-sectional study design, it was not possible to establish a straight cause–effect relationship between vaccine hesitancy and the observed determinants. Furthermore, other studies used between one and three items to measure vaccine hesitancy,Citation10,Citation17,Citation20 whereas vaccine hesitancy was measured using only one item in the present study. The validated 15-item tool developed by Opel et al. was not used since this survey only targets parents of young children.Citation22 In spite of the recruitment procedure that implied first calling the participant to make an appointment and then later answering the survey at the agreed time, our participation rate was quite substantial. However, as with most studies, our sampling may have been affected by a potential selection bias, which means that nonrespondents could have different opinions about immunization compared to respondents. However, weighting methods and the fact that the survey was about health, not only about immunization, partially reduce this nonresponse bias. Weighted data were used in all analyses to ensure a better representation of the population of the Eastern Townships, which allowed for a generalization of the results in the entire region.
Conclusions
This study determined several independent factors influencing vaccine hesitancy among a large population-based sample of individuals residing in the Eastern Townships region. People who consult alternative health-care professionals, smoke cigarettes, have issues of trust with public health authorities, or have a low household income should be particularly targeted by health professionals during immunization counseling. Future strategies to tackle vaccine hesitancy should take into account these determinants.
Methods
Design and sample
A cross-sectional study was conducted between June and October 2014 in the Eastern Townships, a southern region of Quebec (Canada) with 320,000 residents in 2014 (4% of Quebec population).Citation37 A phone survey was administered over a large random digit sample by trained interviewing staff targeting 8,700 adults living in the region. The sample was stratified according to the territory of residence, with half of the sample (n = 3,900) living in Sherbrooke, the main city of the region, and 800 residents from each of the other six territories (n = 4,800). Adults 18 y old and over, living in private households and speaking French or English, were eligible to participate in the study. During the study period, a total of 148 trained interviewers made phone calls between 10:00 am and 9:00 pm on weekdays and 3:00 pm and 9:00 pm on Sundays to check respondent’s eligibility, obtain verbal consent to participate, and schedule appointments for answering the survey. Interviewers then conducted computer-assisted telephone interviews at the agreed appointment based on a structured questionnaire during weekdays between 8:30 am and 5:00 pm. An online version of the survey was also available to respondents if they preferred or were not available for the appointment.
Survey questionnaire
A questionnaire was developed to assess several health topics among the population. Questions were mostly based on validated questionnaires and were determined with the collaboration of university researchers of the Eastern Townships Health Authority. In this case, relevant items, such as questions about physician consultations, perceived health status, life habits, and socioeconomic situation, were considered in this analysis in order to identify independent determinants of vaccine hesitancy.
Items pertaining to immunization knowledge, attitudes, and beliefs were based on the HBM, an established theoretical framework used to examine patient motivations for adopting a preventive health-related behavior,Citation38 and were developed by immunization experts from the Eastern Townships Public Health Department. The HBM has been used before in several studies to assess immunization beliefs and behaviors.Citation39–Citation41 Based on this model, four components were assessed in the present study: perceived susceptibility (i.e., respondent’s beliefs about their risk of getting a condition), perceived severity (i.e., respondent’s concerns about the seriousness of a condition and its consequences), perceived vaccine benefits, and perceived vaccine risks. These four components concerned influenza immunization since this vaccine is indicated for everyone, and as it is recommended every year, participants should remember more easily the reasons for accepting or not receiving it. The other items (perceived knowledge and perceived necessity) concerned general vaccination. Vaccine hesitancy, the main outcome measure in this study, was assessed by one item: “Do you agree with this statement: I am not in favor of vaccination in general”.
Items mainly used a 4-point Likert scale, and the questionnaire was pre-tested in the beginning of June 2014. The study was approved by the CSSS-IUGS Research Ethics Board.
Statistical analyses
Data were weighted according to age, sex, and territory of residence using an iterative method in order to better represent the population of the Eastern Townships. Likert-scaled responses were analyzed as dichotomous variables indicating the respondent’s agreement or lack of agreement with the item (e.g., totally/somewhat agree vs. totally/somewhat disagree). Chi-square tests were performed to explore differences in responses between vaccine-hesitant and non-vaccine-hesitant respondents. Responses “I don’t know” or “Preferred to not answer” for some variables, representing between 0 and 4.7% of all responses, were excluded only in the specific analyses involving those variables.
Univariate logistic regressions were first performed in order to examine each variable individually without adjusting for the effects of others. All statistically significant variables associated with vaccine hesitancy for a significance level set at 0.05 were then introduced into a multivariate model in order to identify independent determinants of vaccine hesitancy. Adjusted odds ratios (aOR) and their respective 95% confidence intervals were calculated. All analyses were conducted using SPSS version 20.0.
Abbreviations
| AOR | = | Adjusted odds ratio |
| CI | = | Confidence intervals |
| HBM | = | Health Belief Model |
| VPD | = | vaccine-preventable diseases |
Disclosure of potential conflicts of interest
No potential conflicts of interest were disclosed.
Acknowledgments
We thank the BIP staff for conducting all the interviews and all the participants of the study. We also thank Dr Marie-France Langlois for giving us access to the survey data about consultations of health-care professionals over the last 12 months and Jade Berbari for English revision of the manuscript.
Additional information
Funding
References
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