“…Lastly, several studies [ 48 , 49 , 50 , 51 , 52 , 53 ] investigated the impact of demographic data (e.g., gender, age, education level, and chronic disease) and COVID-19-related variables (e.g., previous COVID-19 infection, perceived risk, and fear about COVID-19) on nurses’ willingness to accept primary COVID-19 vaccination, but only one study [ 21 ] assessed this willingness toward booster doses. Therefore, we hypothesized the following:…”