Promoter or barrier? Assessing how social media predicts Covid-19 vaccine acceptance and hesitancy: A systematic review of primary series and booster vaccine investigations

Rationale: Prior research indicates that social media is primarily a negative contributor to Covid-19 vaccine outcomes. Objective: The current systematic review of Covid-19 primary series and booster vaccine investigations provides a more nuanced and comprehensive assessment of this association by exploring a) how distinct social media judgments and actions predict different vaccine-related outcomes - perceptions and intentions/uptake, b) both primary series and booster findings, c) types of social media, and d) comparisons across different populations. Method: We conducted a systematic review of published research examining the link between social media and COVID-19 vaccine outcomes – judgments, intentions, and uptake. Overall, we identified 113 published articles. Results: The findings reveal complex associations between distinct social media predictors and these outcomes. The most consistent negative relationships emerge within studies looking at ‘social media as an information source,’ ‘trust’, and ‘general social media use/passive exposure’ as predictors of less favorable vaccine judgments and intentions/uptake. Conversely, studies focused on ‘information seeking’ indicate more mixed results. Among the few booster investigations, there are more positive than negative associations between social media predictors and Covid-19 vaccine intentions. Across different social media platforms and sample populations, social media was a less robust/consistent negative predictor of COVID-19 judgments and intentions. Conclusions: While social media can contribute to more negative COVID-19 vaccine judgments and motivations, the consistency of this relationship may vary across populations, the platforms users access, and the nature of exposure. Overall, social media campaigns promoting COVID-19 vaccines should employ distinct strategies to target those individuals that value social media as an information resource.