Peer Effects on Vaccination Behavior: Experimental Evidence from Rural Nigeria

Understanding how and why social interactions influence people's vaccination behavior is important for disease control. This paper conducts the first causal analysis of peer effects on vaccination behavior in developing countries. We created exogenous variations in peers' vaccination behaviors by randomizing cash incentives for tetanus vaccine take-up among Nigerian women. Vaccine take-up among friends strongly increased women's take-up. The peer effects among friends are heterogeneous according to a person's beliefs about vaccination. We find suggestive evidence of mechanisms underlying the positive peer effects that women visit a clinic together as well as share information about the vaccine.