Do interventions containing risk messages increase risk appraisal and the subsequent vaccination intentions and uptake? A systematic review and meta-analysis

Purpose: There is good evidence that for many behaviours, increasing risk appraisal can lead to a change in behaviour, heightened when efficacy appraisals are also increased. The present systematic review addressed whether interventions presenting a risk message, increase risk appraisal and an increase in vaccination intentions and uptake. Method: A systematic search identified Randomised Controlled Trials of interventions presenting a risk message and measuring risk appraisal and intentions and uptake post-intervention. Random effects meta-analyses investigated the size of the effect that interventions had on vaccination risk appraisal, and on vaccination behaviour or intention to vaccinate, and the size of the relationship between vaccination risk appraisal and vaccination intentions and uptake. Results: Eighteen studies were included and 16 meta-analysed. Interventions overall had small significant effects on risk appraisal (d= 0.161, p= .047) and perceptions of susceptibility (d= 0.195, p= .025), but no effect on perceptions of severity (d= -0.036, p= .828). Interventions showed no effect on intention to vaccinate (d= 0.138, p= .195) and no effect on vaccination behaviour (d= 0.043, p= .826). Interventions typically did not include many Behaviour Change Techniques (BCTs), with the most common BCT unique to intervention conditions being ‘Information about Health Consequences’. Few of the included studies attempted to, or successfully increased, efficacy appraisals. Conclusions: Overall, there is a lack of good quality primary studies, and existing interventions are suboptimal. The inclusion of additional BCTs, including those to target efficacy appraisals, could increase intervention effectiveness. Protocol (CRD42015029365) available from http://www.crd.york.ac.uk/PROSPERO/