Could information about herd immunity help us achieve herd immunity? Evidence from a population representative survey experiment

Abstract

Aims: Immunisation causes dramatic reductions in morbidity and mortality from infectious diseases; however, resistance to vaccination is nonetheless widespread. An understudied issue - explored here - is whether appeals to collective as opposed to individual benefits of vaccination encourage people to vaccinate. Knowledge of this is important not least with respect to the design of public health campaigns, which often lack information about the collective benefits of vaccination.

Methods: Using a between-subjects experimental survey design, we test whether information about the effects of herd immunity influences people's decision to vaccinate. A representative sample of Norwegians was confronted with a hypothetical scenario in which a new and infectious disease is on its way to Norway. The sample was split in three - a control group and two treatment groups. The one treatment group was provided information about collective benefits of vaccination; the other was provided information about the individual benefits of vaccination.

Results: Both treatments positively affect people's decision to vaccinate; however, informing about the collective benefits has an even stronger effect than informing about the individual benefits.

Conclusions: Our results suggest that people's decision about whether to vaccinate and thus contribute to herd immunity is influenced by concern for others. Thus, stressing the collective benefits of vaccination could increase the effectiveness of health campaigns.

Keywords: Altruism; Norway; attitude; compliance; coverage; influenza; pandemic; preventive medicine; public opinion; vaccination.