Influenza vaccine coverage among healthcare workers: A cluster analysis from a cross-sectional survey

Objectives: Influenza vaccination is recommended for healthcare workers (HCWs). However, in a 1500bed tertiary care university hospital in France, influenza vaccine coverage among HCWs was 23% in 2017. Patients and methods: We performed a cross-sectional study between 05/09/2018 and 25/09/2018 among HCWs, randomly selected independent of their vaccination status, to estimate influenza vaccination coverage rate during the 2017-2018 season, and explore factors influencing vaccination, using a questionnaire. Multivariable regression analysis to assess factors associated with vaccine uptake and hierarchical clustering on principal components to identify HCW profiles regarding factors influencing vaccine uptake, were performed after multiple imputation. Results: 977 HCWs were included (68% participation rate), primarily females (84%), nurses (38%) of 18- 39 years old. Influenza vaccination coverage rate reached 33[30-36]%. Frequent vaccination (aOR 39.27 [21.52-74.51]) and personal/family medical history of influenza (aOR 3.33[1.16-10.02]) were independently associated with vaccination. In HCWs' patterns of influenza vaccination status, three clusters were identified: 1) (n = 438) mostly vaccinated (70%); 2) (n = 507) most unvaccinated (97%); and 3) (n = 32) unvaccinated HCWs lacking knowledge on influenza and influenza vaccine. Among the 148 (15%) HCWs reluctant to receive the vaccine the following year, 23 (16%) received it for the 2017-2018 season, while 125 (84%) did not, mostly stating they had doubts about the vaccine (82%). Conclusion: This work identifies determinants of vaccine uptake and highlights HCWs profiles associated with factors influencing vaccination and a subgroup of HCWs flexible about having the vaccine during the upcoming seasonal campaign. This result opens up perspectives toward improved vaccination coverage among HCWs.