A Social Norms Intervention to Improve Vaccination Intentions: Outcomes from the <i>Happy Baby Program</i> in the Slum Areas of Varanasi, India

The extent to which social norms can be changed through social media and whether those changes affect behaviors are questions raised in this paper. Using the Theory of Normative Social Behavior, we do so in the context of promoting childhood immunization in slum areas in India, where rates remain critically low. We used a quasi-experimental design to compare outcomes across three arms: a no-intervention Control Arm (<i>n</i> = 602), a Vaccine Arm (<i>n</i> = 626) that received information about vaccines through text, audio, and video on WhatsApp, and a Wellness Arm (<i>n</i> = 651) that received information about vaccines and wellness (breastfeeding, handwashing, and nutrition) in the same format and frequency as the Vaccine Arm. Longitudinal data were collected at baseline and end-line from all three arms. Significant improvements in descriptive and injunctive norms about vaccination, self-efficacy, and vaccination intentions were observed in the Vaccine Arm, compared to the Control Arm. The two (descriptive and injunctive) norms also improved significantly in the Wellness Arm, compared to the Control Arm. Changes in self-efficacy and descriptive norms also affected changes in intentions. These findings provide a pathway for future interventions, to improve social norms as a way to improve vaccination. We discuss a few mechanisms for doing so.