Evaluating source credibility effects in health labelling using vending machines in a hospital setting.

OBJECTIVES: Providing advice to consumers in the form of labelling may mitigate the increased availability and low cost of foods that contribute to the obesity problem. Our objective was to test whether making the source of the health advice on the label more credible makes labelling more effective. METHODS AND MEASURES: Vending machines in different locations were stocked with healthy and unhealthy products in a hospital. Healthy products were randomly assigned to one of three conditions (i) a control condition in which no labelling was present (ii) a low source credibility label, "Lighter choices", and (iii) a high source credibility label that included the UK National Health Service (NHS) logo and name, "NHS lighter choices". Unhealthy products received no labelling. The outcome measure was sales volume. RESULTS: There were no main effects of labelling. However, there were significant interactions between labelling, vending machine location and payment type. For one location and payment type, sales of products increased in the high credibility label condition compared to control, particularly for unhealthy products, contrary to expectations. CONCLUSIONS: Our findings suggest that high source credibility health labels (NHS endorsement) on food either have little effect, or worse, can "backfire" and lead to effects opposite to those intended. The primary limitations are the limited range of source credibility labels and the scale of the study.

Identifying reasons for non-acceptance of influenza vaccine in healthcare workers: an observational study using declination form data.

BACKGROUND: Healthcare workers are sometimes required to complete a declination form if they choose not to accept the influenza vaccine. We analysed the declination data with the goal of identifying barriers to vaccination uptake across seasons, staff groups, and pre- and post- arrival of COVID-19. METHODS: Reasons for declining the vaccine were gathered from N = 2230 declination forms, collected over four influenza seasons, 2017/2018, 2018/2019, 2019/2020 and 2020/2021, from a single health board in the UK. Reasons were classified according to ten categories and the resulting distribution analysed across year and staff groups. A further analysis considered the two most prevalent categories in more detail. RESULTS: Fear of adverse reactions and Lack of perception of own risk were identified as primary reasons for not accepting the vaccine across time and across staff groups. However, there was no evidence that Lack of concern with influenza, or Doubts about vaccine efficacy was prevalent, contrary to previous findings. Overall, reasons fitted a pattern of underestimating risk associated with influenza and overestimating risk of minor adverse reactions. There were also differences across years, χ2(24) = 123, p < .001. In particular, there were relatively fewer Lack of perception of own risk responses post-COVID-19 arrival than before, χ2(8) = 28.93, p = .002. CONCLUSION: This study shows that data collected from declination forms yields sensible information concerning vaccine non-acceptance without the difficulties of retrospective or pre-emptive reasoning suffered by questionnaires. Our findings will aid messaging campaigns designed to encourage uptake of the influenza vaccine in healthcare workers. In particular, we argue for an approach focused on risk perception rather than correction of straightforward misconceptions.

The health benefits and cost-effectiveness of complete healthy vending.

Vending machines contribute to growing levels of obesity. They typically contain energy dense, high fat snacks and attempts at persuading consumers to switch to healthier snacks sold within the same machine have had limited success. This study explored the health benefits and cost effectiveness of the complete replacement of regular snacks with healthy items. Two vending machines were manipulated in a 6-month trial, with a healthy and regular range of products alternated between the two machines every fortnight. Healthy vending resulted in a 61% drop in calories sold relative to regular vending, significant with time and product range as random factors. There was no evidence of compensatory behaviour from nearby shop sales nor in multi-item purchases from vending machines. The impact on profit was less clear. Sales dropped by 30% during healthy vending but variability across product range meant that the change was not significant. Overall our results demonstrate that complete healthy vending can be introduced in hospitals without a catastrophic loss in sales nor compensatory behaviours that offset the public health gains of consuming healthier products.