The effect of moral appeals on influenza vaccination uptake and support for a vaccination mandate among health care workers.

Objective: Influenza vaccination uptake among health care workers (HCWs) protects patients and staff. Still, many health institutions' coverage rates are unsatisfactory. We aimed to test the effect of communicating moral appeals in increasing vaccination uptake in a real life setting.

Method: In three field experiments among HCWs, a moral appeal highlighting morally relevant consequences of influenza vaccination was manipulated. The outcome variables were vaccination intention right after exposure to the moral appeal (Study 1; N = 569 US and UK HCWs from various institutions) and vaccination uptake in subsequent weeks for those respondents who consented in sharing this data during the survey (Studies 2 and 3, respectively N = 121 and N = 770 Dutch hospital employees).

Results: Studies 1 and 3 showed that moral appeal enhanced vaccination intention and uptake (vaccination uptake increased by 11%), due to increased awareness that vaccination is a moral decision. In Study 2, moral appeal had no effect, probably because people with more outspoken vaccination attitudes had responded to the call to fill in the survey. Moreover, moral appeal increased support for an influenza vaccination mandate. Furthermore, the results suggest that moral appeal was especially effective among HCWs with no history of influenza vaccination.

Conclusion: These results indicate that moral appeal can be a useful tool for increasing both vaccination uptake and mandate support within health care institutions.