Flu and COVID-19 Vaccination: What Happens to the Flu Shot When the Campaigns Overlap? Experience from a Large Italian Research Hospital

Influenza represents a threat to global health and health care workers (HCWs) have an increased risk of contracting the influenza virus in the workplace. The COVID-19 pandemic has brought back the importance of influenza vaccination, as the influenza virus can circulate together with SARS-CoV-2. The aim of this report is to describe the actual flu vaccination coverage among healthcare workers of a research hospital and the trend changes, with respect to the past flu vaccination campaigns, in light of the present pandemic and COVID-19 vaccination. A Pearson’s χ(2) test was used to test the correlation of flu vaccination coverage, across all professional categories, between the last two years. A linear regression model was adopted to predict the total vaccination coverage of this year. A statistically significant decrease (p < 0.01) was observed in vaccination coverage among all the professional categories with a 50% reduction in vaccination trends between the last two years. Analyzing the data from the previous six flu vaccination campaigns, the expected value, according to the linear regression model, was estimated to be 38.5% while the observed value was 24%. The decrease in vaccination coverage may be due to the fear of the pandemic situation and especially to the uncertainty related to the consequences of a concurrent administration which may overload the immune system or may be more reactogenic. The COVID-19 pandemic represents an opportunity to promote and support large-scale influenza vaccination among HCWs through structured programs, adequate funding, and tailored communication strategies.