Associations between vaccination and protective behaviors against COVID-19: transfer and redundancy effects as potential psychological mechanisms

This study aimed to investigate mechanisms explaining associations between vaccination and protective health behaviors during the COVID-19 pandemic. The study used a secondary analysis of data from a longitudinal online study at four time points between April 2020 and March 2021. Two hundred and forty participants responded to questionnaires assessing adherence to multiple COVID-19 protection behaviors, COVID-19 vaccination, behavioral specific outcome expectancies and general healthy lifestyle. Statistical analyses included z statistic for differences between correlations and moderation analysis by the SPSS PROCESS macro. The correlation between initial adherence to protective behaviors prior to availability of vaccination and actual vaccination was positive, but when vaccination was available, the concurrent correlation between these behaviors was null. Healthy lifestyle and outcome expectancies moderated the association between vaccination and adherence to protection behaviors. These results were explained by a ‘redundancy effect’, conceptualized as beliefs that engagement in specific health behaviors justifies evading other health behaviors. The ‘redundancy effect’ cancelled the initial positive correlation between vaccination and protective health behaviors, produced by a ‘transfer effect’, based on similarities between the perceived purposes of those behaviors. Theoretical and practical implications of the findings were discussed.