TY - JOUR T1 - When do persuasive messages on vaccine safety steer COVID-19 vaccine acceptance and recommendations? Behavioural insights from a randomised controlled experiment in Malaysia JF - BMJ Global Health JO - BMJ Global Health DO - 10.1136/bmjgh-2022-009250 VL - 7 IS - 7 SP - e009250 AU - Nicholas Yee Liang Hing AU - Yuan Liang Woon AU - Yew Kong Lee AU - Hyung Joon Kim AU - Nurhyikmah M Lothfi AU - Elizabeth Wong AU - Komathi Perialathan AU - Nor Haryati Ahmad Sanusi AU - Affendi Isa AU - Chin Tho Leong AU - Joan Costa-Font Y1 - 2022/07/01 UR - http://gh.bmj.com/content/7/7/e009250.abstract N2 - Introduction Vaccine safety is a primary concern among vaccine-hesitant individuals. We examined how seven persuasive messages with different frames, all focusing on vaccine safety, influenced Malaysians to accept the COVID-19 vaccine, and recommend it to individuals with different health and age profiles; that is, healthy adults, the elderly, and people with pre-existing health conditions.Methods A randomised controlled experiment was conducted from 29 April to 7 June 2021, which coincided with the early phases of the national vaccination programme when vaccine uptake data were largely unavailable. 5784 Malaysians were randomly allocated into 14 experimental arms and exposed to one or two messages that promoted COVID-19 vaccination. Interventional messages were applied alone or in combination and compared against a control message. Outcome measures were assessed as intent to both take the vaccine and recommend it to healthy adults, the elderly, and people with pre-existing health conditions, before and after message exposure. Changes in intent were modelled and we estimated the average marginal effects based on changes in the predicted probability of responding with a positive intent for each of the four outcomes.Results We found that persuasive communication via several of the experimented messages improved recommendation intentions to people with pre-existing health conditions, with improvements ranging from 4 to 8 percentage points. In contrast, none of the messages neither significantly improved vaccination intentions, nor recommendations to healthy adults and the elderly. Instead, we found evidence suggestive of backfiring among certain outcomes with messages using negative attribute frames, risky choice frames, and priming descriptive norms.Conclusion Message frames that briefly communicate verbatim facts and stimulate rational thinking regarding vaccine safety may be ineffective at positively influencing vaccine-hesitant individuals. Messages intended to promote recommendations of novel health interventions to people with pre-existing health conditions should incorporate safety dimensions.Trial registration number NCT05244356.Data are available upon reasonable request. The data set used for this study belongs to the Ministry of Health, Malaysia. Hence, the data set may be available from the corresponding author via a formal request through relevant authorities at the Ministry of Health, Malaysia. ER -