Adult Vaccination as Part of a Healthy Lifestyle: Moving from Medical Intervention to Health Promotion

"Message framing is...crucial: while risk - both of disease and of potential vaccine-related adverse events - needs to be addressed, it may be more productive to focus more on benefits (both to the individual and to society at large) and social norms."

The global population is ageing rapidly, partly because vaccination has reduced deaths from complications of co-existing chronic conditions and directly from vaccine-preventable disease (VPD). However, most vaccination programmes today - and, thus, vaccine education efforts - are focused on reducing mortality and morbidity in children, even though the major burden of VPDs is in adults. Despite the attested benefits, vaccination coverage is almost always poor in adults, even in countries where access is free at point of care. The authors of this narrative review argue that adult vaccination will only be successful if it respects individual autonomy. They suggest that understanding - and communicating about - vaccination as a health-promoting activity undertaken by agents driven by self-care could help improve vaccination uptake among adults.

The first part of the narrative review introduces the effects that demographic changes are having on vaccination planning, discusses how vaccination has contributed in part to this demographic change, and examines studies suggesting that adult vaccination has broad health benefits beyond the prevention of a few targeted acute diseases. The authors suggest (based on responses of adults to surveys on vaccination) that an imperfect analysis of the personal risks and benefits of vaccination may decrease the likelihood of an adult to accept vaccination. They argue that addressing these psychological/educational barriers can provide synergistic improvements in quality of life and healthcare delivery that go beyond those normally associated with prevention of individual VPDs.

The second part of the review introduces the concept of healthy ageing, particularly with regard to vaccination, considers why adult vaccination appears to consistently lag behind paediatric vaccination, and suggests some potential routes to addressing this. Observing that campaigns to improve adult vaccination coverage - like campaigns to improve exercise or diet habits - have relied primarily on education in order to spark behaviour change, the authors go on to look at what has - and has not - worked in this context.

Namely, the authors identify these characteristics of a successful public health campaign:

• An evidence base that provides a convincing case for taking action - for policymakers, for healthcare providers, and for the general public.
• Political commitment, provision of resources, and support for actions.
• An environment and infrastructure that supports the intended audience to make the desired health behaviour changes.
• Acceptance and support of the message delivered by healthcare community.
• Delivery of a simple, effective message to a sufficient proportion of the audience to ensure the campaign's messages and themes are broadly known and carry sufficient weight in the overall media landscape.
• Process analysis with rigorous monitoring and evaluation to allow midcourse corrections and programme improvement.

On the other hand, some media campaigns have had unintended or even counterproductive consequences. This may be a particular risk when dealing with a topic that has a high social media profile such as vaccination, where the message delivered by health authorities will inevitably be seen in the context of ongoing media discussion. In Vietnam, for example, hepatitis B vaccination coverage fell from 64.3% to 26.9% in the course of 2012-2013, despite a government campaign to promote vaccination. The apparent cause was media discussion on possible links between the vaccine and deaths. Even though investigation later showed no casual links, in the public mind the discussion increased fear of side effects. A subsequent study found that 68.2% of people asked became vaccine hesitant after hearing about possible adverse events in the media, with 12.4% stating that they would refuse vaccination. Similar findings have been reported from China, Italy, and Canada.

Surveys cited here indicate that common reasons for hesitancy include factors such as an overestimation of the frequency and severity of side effects associated with vaccination, a lack of confidence in effectiveness of the vaccine (particularly for influenza), an underestimation of the potential seriousness of the disease, and a belief that the personal risk from disease is low. In contrast, among the reasons for accepting vaccination are a desire to be protected against disease and the belief that it is a social norm to vaccinate. Considering that behavioural change techniques ("nudging") to vaccine information may have a positive effect on individuals' intent to vaccinate, the authors propose that the following points may be beneficial when considering programmes aimed at boosting adult vaccination:

• Present the full scope of risk that can be averted by vaccination (though risks should not comprise a disproportionate amount of the message) - This should be presented as concrete potential outcomes, such as loss of income or employment due to influenza. This information needs to be personalised for the audience targeted - for example, adults in early employment or university have different risks and different concerns than retired persons.
• Emphasise the benefits of choosing vaccination for the individual - While the social benefits of vaccination are important, the benefits presented should be tangible and relevant to individuals.
• Address concerns about efficacy - Message framing is important. As an example, stating that influenza vaccination is only 30% effective at preventing disease is technically the same as stating that if you get vaccinated you reduce your risk of disease by about one-third. However, the former message is more likely to be perceived as highlighting a low level of effectiveness.
• Provide plausible paths to action - Educational campaigns that aim to make vaccination a "health-promoting activity" will need to be matched by healthcare capacity.
• Ensure there are mechanisms for feedback and assessment of impact - Cultural and economic differences may mean that what is successful in one setting may not be feasible or effective in another.

In conclusion: "Based on the evidence available, promoting life course vaccination and healthy ageing concepts, where vaccinations are considered as part of a package of health behaviours designed to promote health and well-being in adults and older adults, rather than being seen primarily as measures to prevent transmission of disease from specific pathogens, may be a way to generate such a paradigm shift. This approach will require an understanding and acceptance of this viewpoint by the general population and health authorities alike."