Background

In the past two decades, childhood vaccination coverage has increased dramatically, averting an estimated 2–3 million deaths per year, along with myriad episodes of illness and disability.1 ,2 Adult vaccination coverage, however, remains poorly recorded and substandard.2 ,3

Two important adult routine vaccines are seasonal influenza (flu) and tetanus-containing vaccines.4 An annual flu vaccine is recommended to all adults, particularly those aged ≥65 years and under 65 years with certain medical conditions such as asthma, heart disease and diabetes. Despite this recommendation, in any given year, flu epidemics can cause between 500 000 and 1 000 000 deaths globally.5 A tetanus-containing booster is recommended every 10 years to prevent tetanus and other diseases such as pertussis, diphtheria and polio. Although tetanus morbidity and mortality is mostly neonatal and maternal, globally, an estimated 13 000 annual non-maternal adults deaths are due to tetanus infection.6 Moreover, it has been established that unvaccinated adolescents and adults, or those with waning immunity, have become a major source of pertussis infection for unvaccinated infants.7 The WHO estimated that, in 2008, 195 000 children under 5 years of age died from pertussis and 199 000 from flu, many of whom were infected by an adult.8

Although structural barriers, such as access to care and vaccine availability, are known to limit coverage, social and psychological factors can also affect vaccine uptake. For example, perceived susceptibility to flu and concerns about vaccine safety and effectiveness have been shown to significantly influence vaccination behaviour.9 ,10 The relevance of these factors to vaccination decisions has become a focus of policy discussions, such that national and supranational immunisation advisory committees are now evaluating how to best measure confidence in vaccines to inform and evaluate future interventions.11

Making decisions about our own health in general, and vaccinations in particular, can be a difficult task. Typically, it involves navigating an often intricate healthcare system, discussing the issue with a healthcare professional (HCP), researching the Internet, consulting family members and peers and trying to make sense of all the available information, which is likely to be incomplete and conflicting.12 A key challenge in decision-making processes regarding health is weighing up the benefits of an intervention versus its potential harm. In the case of vaccinations, this process can be particularly complex as it often entails the assessment of several disease-related variables including severity, likelihood of catching the pathogen and susceptibility to it, as well as vaccine attributes such as effectiveness, side effects and safety, among others.13 Furthermore, the benefits and drawbacks of vaccines are normally conveyed in statistical terms, a language that has proven to be difficult to grasp for most people. For example, results from an experimental study showed that 16–20% of highly educated participants incorrectly answered relatively simple questions about risk magnitudes (eg, Which represents the larger risk: 1%, 5% or 10%?).14 It is, therefore, conceivable that a significantly larger proportion of less-educated individuals, who constitute a majority of the population, are likely to misunderstand this type of data.

A vast body of research has demonstrated that when people are unable to assess risk using statistical reasoning they often rely on heuristics, an experience-based and intuitive approach used to facilitate decision-making.15–17 Heuristics represent what psychologists have termed ‘cognitive shortcuts’; in other words, they allow an inference to be made regarding risk without going through numerous analytical calculations. By its very nature, the use of heuristics can be efficient and accurate in some occasions, but it can also lead to cognitive errors and flawed decision-making when used in circumstances that require thorough logical analysis.18 Furthermore, individuals’ judgement is often influenced by their context and personal or family experiences, whether these are conscious or not.19 Health decisions in general, and vaccination decisions in particular, can also be significantly influenced by patients’ trust in HCPs and the latter's ability to communicate risk effectively.20

Although qualitative studies have explored beliefs, attitudes and preferences associated with flu vaccination uptake, thus far, little research has investigated how participants’ own context and experiences influence their vaccination decision-making process over time.21–23 Furthermore, most studies focus on populations from developed countries; relevant evidence from developing countries is largely missing. Qualitative research on adult tetanus boosters is limited and focuses on neonatal tetanus.

This paper aims to provide a detailed account of a mixed method qualitative approach designed to understand the wider constellation of social and psychological factors likely to influence adult vaccination behaviour, and their relative importance, as well as the context in which these decisions take place. Our focus is on social influences, beliefs and attitudes affecting the uptake of seasonal flu vaccines and tetanus boosters, as these aspects have been found to be particularly influential in vaccination decision-making. Our research will be conducted in key developed and developing economies—the USA, the UK, France, India, China and Brazil.

Conceptual framework

Our research sits well within the constructivist (or interpretivist) paradigm, which is concerned with people's experiences from the perspective of those who live them, and whereby the researcher and participant ‘jointly create findings from their interactive dialogue and interpretation’.24 From an epistemological point of view, however, our position draws from constructivism and positivism, in that we recognise there is a degree of bias introduced by the researcher's experience when creating knowledge, but the researcher will endeavour to be objective and to elicit the participant's experience in an unprejudiced manner.25

The methodology of this study rests on two theoretical approaches: heuristics and biases, specifically the availability heuristic26 and customer journey mapping.27–29 We explain these below.

As mentioned in the previous section, people rely on a limited number of heuristics which reduce the complexity of calculating probabilities and predicting outcomes to simpler mental operations. A frequently used heuristic is availability, the tendency to make judgements about the frequency or probability of an event based on the ease with which a similar episode can be recalled.30 The use of this heuristic could yield accurate actions but it could also lead to erroneous decisions. For example, a high-risk individual may be prompted to have a flu vaccine after being exposed to extensive media coverage about one single flu-related death. The following season, he may decide not to have the flu vaccine due to a friend experiencing side effects (eg, flu-like symptoms) after receiving a flu vaccine. In both cases, his decision-making is determined by the ease with which the risks associated with flu or the flu vaccine spring to mind (which vary between the two seasons), as opposed to the statistical probability of experiencing either adverse effect (which may be constant across the two seasons). The first decision, however, is aligned with current vaccination recommendations, whereas the second is not.

In addition, it has been established that people's evaluation of the logical strength of an argument is often biased by their pre-existent belief in the truth or falsity of the conclusion.31 For example, if the same high-risk individual distrusts the medical establishment and the pharmaceutical industry and prefers alternative medicine instead, it is likely that the news about a flu-related death will have a lesser impact on his vaccination decision than his friend's reported side effects—due to mentally overweighting the adverse effects of the vaccine, which are consistent with his pre-existing beliefs. Importantly, belief-based decision-making need not be conscious.32 ,33 Thus, a decision based on intuition may be later postrationalised and explained using analytical-sounding arguments, when, in reality, cost–benefit analysis was not employed.

The customer journey mapping approach is commonly used in service design to capture and evaluate people's experience of different services. Although some elements may be more important than others, this approach considers the overall experience of the service user as the result of every element in a journey through a service. The customer journey mapping approach has been mainly used by the transport and tourism industries, yet it has also enabled health providers to improve their services by uncovering key areas which deserve attention and focus improvement efforts on such areas.34 Of particular note is the brand touchpoint wheel developed a decade ago by Dunn and Davies.35 They conceive the customer journey as a wheel comprising three main stages (prepurchase, purchase and postpurchase experience) and a number of touchpoints, which are key points at which the consumer interacts with a particular product or service (see figure 1).

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Figure 1

The brand touchpoint wheel. Source: Dunn and Davis.35

Our approach: journey to vaccination

Most qualitative studies in the field of vaccination decision-making have elicited barriers and enablers to vaccination using traditional methodological approaches such as explicit enquiry (eg, why did you vaccinate?) and indiscriminate use of probes, often within a focus group setting. A key shortcoming of these approaches is that the impact of individuals’ personal circumstances and past experiences on vaccination decisions over time is seldom explored. Thus, researchers may fail to notice participants’ tendency to fall back on readily available information and report postdecisional rationalisations of their behaviours rather than actual drivers.

In an effort to address these shortcomings, we developed a new qualitative approach which we call journey to vaccination. Anchored on the two complementary lines of thought described above and nested within the qualitative research tradition, journey to vaccination is a visual exercise in which the interviewer and the participant jointly build a timeline that captures salient events that lead the participant to get or not to get vaccinated. The exercise starts with a participant's latest flu or tetanus vaccination experience as an adult; it then extends backwards to the participant's first memory of such experience. The participant is asked to describe these events, which in turn allows the interviewer to indirectly elicit a range of factors that affected positively or negatively the decision to get vaccinated. Importantly, this exercise enables the participant to produce a personal historical narrative, through which vaccination decisions are discussed as a continuum and not in isolation from each other or from other important health-related or lifestyle-related decisions.

The journey to vaccination approach is designed to comprehensively capture psychological and also social influences on vaccination decisions. Participants are, therefore, asked to recall key actors who were involved in the vaccination process (eg, their family) and how they influenced the process. Emotional aspects of the decision-making are also explored and taken into account.

On the basis of the customer journey mapping approach described earlier and previous evidence on vaccination behaviour, we envisage a journey to vaccination to comprise three stages and a number of touchpoints at which the individual interacts with related health services (figure 2): (1) prevaccination period (appointment with HCP, information—websites, news, vaccination campaigns, peers—and HCP reminders); (2) the vaccination experience itself (location, consultation experience and vaccination experience) and (3) a postvaccination experience (vaccine quality—eg, side effects, effectiveness—and postvaccination advice or information—from HCP, peers and other sources).10 ,35 ,36 An important component of a journey to vaccination is a cue to action or trigger, which consists of an internal or external stimulus (eg, salient health-related experiences, advice from a relative) that prompts individuals to vaccinate or not to vaccinate. Existing evidence suggests that vaccination triggers may usually take place during the prevaccination stage and could sometimes overlap with vaccination touchpoints.10 For example, a vaccination reminder letter from the general practitioner would be a trigger and a touchpoint, if participants explicitly mention that the letter prompted them to vaccinate.

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Figure 2

Journey to vaccination.

Figure 3 illustrates a journey to flu non-vaccination of a participant from a UK pilot (see Procedure section) who is not at high risk (ie, not eligible for free vaccination). The participant mentioned that an allergy to penicillin discovered when he was younger, which his doctor refused to acknowledge, had made him anxious about other medications’ side effects, including vaccines. This was recorded as the first relevant touchpoint and trigger away from vaccination. He then pointed out that some time ago he had heard on the news that there had been flu-related deaths, and that this had been a cause for concern which made him consider having a flu shot (another touchpoint and trigger to vaccination). Subsequently, he recalled having the flu and worrying about the consequences of being out of work due to his self-employed status (trigger to vaccination). The participant then reported that at that stage he had tried to get a flu vaccine at a pharmacy, but it was out of stock (touchpoint and trigger away from vaccination). Finally, the participant remembered that the vaccine could have side effects and decided to stop trying to get vaccinated (trigger away from vaccination). This journey, therefore, does not include a postvaccination stage. Importantly, analysis of the participant's account of his journey to non-vaccination indicates a tendency to make decisions based on heuristics rather than logical analyses. For example, the participant's motivation to have a flu shot after hearing on the news about flu-related deaths was based on the mental availability of this piece of information and not his actual risk of death from flu.

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Figure 3

Example of a journey to flu non-vaccination.

Study aims

The primary aim of this study was to gain deeper understanding of the social and psychological factors influencing the uptake of two different adult vaccines across key high-income and middle-income countries with diverse healthcare systems: the USA, the UK, France, India, China and Brazil. Specifically, we are interested in exploring how people's experiences shape their beliefs, attitudes and behaviour towards vaccines. A secondary objective was to develop more effective methods to elicit such data.