Author: 
Melanie Marti
Monica de Cola
Noni E. MacDonald
Laure Dumolard
Philippe Duclos
Publication Date
March 1, 2017
Affiliation: 

World Health Organization, or WHO (Marti, de Cola, Dumolard, Duclos); Dalhousie University, IWK Health Centre and Canadian Center for Vaccinology (MacDonald)

Vaccine hesitancy is defined as a delay in acceptance or refusal of vaccines despite available vaccination services. Measuring vaccine hesitancy and its determinants worldwide can clarify the scope of the problem and help guide the development of evidence-based strategies to address it. This paper examines 2 indicators that were developed to capture the nature and scope of vaccine hesitancy at the national and subnational level.

The Decade of Vaccines (DoV) Global Vaccine Action Plan (GVAP) 2011–2020 set 6 Strategic Objectives for the decade, with proposed indicators to monitor and evaluate progress. The Strategic Advisory Group of Experts (SAGE) on Immunization Working Group on Vaccine Hesitancy developed 2 new indicators for the second Strategic Objective: Individuals and communities understand the value of vaccines and demand immunisation as both their right and responsibility. These indicators were as follows:

  1. The top 3 reasons for not accepting vaccines according to the national schedule in the past year and whether the response was opinion or assessment-based; and
  2. Whether an assessment (or measurement) of the level of confidence in vaccination had taken place at national or subnational level in the previous 5 years.

In an effort to monitor the existence, global progress, and related determinants of vaccine hesitancy, the World Health Organization (WHO) and United Nations Children's Fund (UNICEF) included the vaccine hesitancy indicators in the Joint Reporting Form (JRF) to collect country data for 2014 (referred to as 2014 JRF data). The JRF is a standardised questionnaire that is sent to all 194 WHO/UNICEF Member States on an annual basis. Most often, it is national immunisation managers who complete the questionnaire.

The main factors influencing vaccine hesitancy in each country in 2014 were analysed using both quantitative and qualitative methods. As a means of interpretation, the responses were categorised according to the matrix of determinants developed by the SAGE Working Group on Vaccine Hesitancy (see Figures 2-4 in the paper on pages 3-4). The matrix of determinants displays the specific drivers influencing the behavioural decision to accept, delay, or reject some or all vaccines in 3 different categories: contextual influences, individual and group influences, and vaccine and vaccination-specific influences. (The WHO matrix of determinants was demonstrated to be robust, as only a few factors identified in the survey fell outside of the scope of the matrix.) The analysis focused on low- and lower-middle-income countries with the largest population size, which are the priority countries for WHO.

The findings from the 2014 JRF data survey are consistent with previous observations that vaccine hesitancy varies by time, place, and vaccine. Overall, however, the results highlight specific factors contributing to vaccine hesitancy across regions and suggest that vaccine hesitancy affects all countries regardless of income status. Major issues were fear of side effects, distrust in vaccination, and lack of information on immunisation or immunisation services. The most frequently cited reasons for vaccine hesitancy globally related to:

  • The risk-benefit of vaccines - "However, since alleged vaccine safety issues are known to have triggered prominent episodes of vaccine hesitancy in developing as well as developed countries,...immunization managers may have felt compelled to place it on the list, Therefore, the information provided by the immunization manager may be subjective, which highlights one general limitation of this indicator."
  • Knowledge and awareness issues - "This was a common concern in low-and lower-middle-income countries. Addressing the gaps in knowledge may help decrease vaccine hesitancy. However, determinants such as education enable and well as hinder immunization uptake."
  • Religious, cultural, gender or socio-economic factors - "However, the religion or belief was often not specified...[I]n countries where religion and culture are barriers to immunization, more work needs to be done with religious leaders to determine the precise concerns and then review if this truly has a religious basis or not. One must be aware that sometimes religious concerns are cited to cover up underlying concerns or to bring attention to a community where problems other than vaccines need to be addressed."

The top 3 reasons in each region are summarised in Figure 6 on page 7. When comparing the results across regions, there was consistency in the causes provided across regions. However in the Region of the Americas (AMR), communication and the media environment were often cited. Some immunisation managers specifically pointed to the impact of increasing anti-vaccination lobbyists and misinformation quoted in the media as a driving factor for vaccine hesitancy.

Globally, only 7% of the immunisation managers (n = 13) indicated no knowledge of vaccine hesitancy within their country, noted that vaccines were well received by the population, or both.

The analysis also revealed that 29% of all countries had done an assessment of the level of confidence in their country, suggesting that vaccine confidence was an issue of importance. Furthermore, it is noteworthy that the number of assessments per year increased over the time period surveyed.

The authors of the paper indicate that "results of the vaccine hesitancy indicators from the 2014 JRF data provide useful insights for global program planning and for tracking of hesitancy. However, they still fall short of measuring the depth and breadth of the hesitancy problem. Nevertheless, the indicators support tracking of perceived reasons for vaccine hesitancy within a country and summarize the kind of surveys conducted thus far that have aimed to assess vaccine confidence."

They continue, writing: "The 2 indicators evaluated herein may assist with advocating and raising awareness of vaccine hesitancy within countries. They may also stimulate action, thorough assessment and identification of the specific determinants of vaccine hesitancy within a country or sub-country level. Evidence-based strategies can only be tailored to address these causes successfully if the underlying determinants of hesitancy in that context are well understood."

Source: 

PLoS One. 2017 Mar 1;12(3):e0172310. doi: 10.1371/journal.pone.0172310. eCollection 2017.