Backfire effect of salient information on vaccine take-up experimental evidence from scared-straight intervention in rural northern Nigeria

Vaccination is the most cost-effective way to prevent mothers and infants from contracting tetanus. However, developing countries struggle with the persistent low take-up of vaccination. The low risk perceptions of disease can be one of the barriers to vaccination. One way to increase the risk perceptions of disease is to use salient loss-framed messages to highlight negative consequences of not getting vaccinated. We conducted a randomized controlled trial among 1,660 women in 80 villages in northeastern Nigeria. Respondents were randomly assigned to view one of two flipcharts: (1) control flipcharts, which contained written explanation about the severity of the disease, or (2) `scared-straight' flipcharts that contain the salient information about the disease severity in addition to the written explanation about the severity of the disease. Additionally, respondents were provided randomly assigned amounts of cash incentives. The scared-straight intervention backfired among women with no previous experience of tetanus vaccination: it decreased their vaccine take-up by 3.7-6.1 percentage points, even though it increased their perceived risk of disease and their fear level. The negative effect of the scared-straight intervention is the most prevalent among women who received the lowest amount of cash incentive. Women without experience of tetanus vaccination might have responded to the scared-straight flipcharts by denying the information provided because the flipcharts were too frightening. The use of the scared-straight tactic is not recommended to aim for the improved take-up of vaccination in developing countries where people might face budget constraints for achieving desirable behaviors. Trial Registration: The trial was registered at ISRCTN registry (ID: ISRCTN95083356).