From hesitancy to decision: shifts from intentions to uptake of Influenza and COVID-19 vaccines

Abstract Background Vaccine hesitancy is context-related and risks coverage. In a context of growing hesitancy, this study aims to characterize and identify factors underlying shifts in Influenza and COVID-19 vaccines intention and uptake. Methods Questionnaires were administered to a random sample of the 60+ years old Portuguese population (n = 1400), before (Q1) and at the end of the campaign (Q2). Sociodemographic, clinical data and intention to Influenza/COVID-19 vaccine uptake, using a Likert-scale (0-2: refusal; 3-7: hesitancy; 8-10: acceptance), were assessed on Q1. On Q2, self-reported vaccination status and motives. A logistic regression was performed to identify underlying factors. Results COVID-19 vaccine: 26.2% of those reporting acceptance went for non-uptake (214/818), stating low susceptibility/severity and fear of side effects. Factors associated were not having chronic disease (OR 2.07, p<.05) and age 60-64 (OR 4.16, p<.05). 25.5% of those who refuse went for vaccine uptake (27/106), stating self-initiative. Age 65 + (OR 43.82, p<.05) was associated with the shift; 56.4% of the hesitant individuals went for non-uptake (154/273). Higher education associates with non-uptake (OR 0.53, p<.05). Influenza vaccine: 11.5% of reported acceptance went for non-uptake (100/873), stating low susceptibility/severity. Associated factors were age 60-64 (OR 5.85, p<.05), not having chronic diseases (OR 2.64, p<.05) and living alone (OR 2.34, p<.05). 23.4% of those refusing decided for vaccine uptake (29/124), stating self-initiative/risk awareness. Associated factor was age 60-64 (OR 6.41, p<.05). 69.5% of hesitancy went for uptake (139/200). Chronic disease associates with non-uptake (OR 0.26, p<.05). Conclusions Intention is a good predictor but not decisive for uptake. This research provides better understanding of shifts in intention versus vaccine uptake, as well as factors and motives for hesitancy, allowing more robust interventions ahead of a vaccination campaign. Key messages • For the Influenza vaccine, 13% of individuals reporting acceptance or refusal changed their mind. From the group reporting hesitancy, 70% decided for vaccine uptake. • For the COVID-19 vaccine, 26% of individuals reporting acceptance or refusal changed their mind. From the group reporting hesitancy, 56% decided for non-vaccine uptake.