Impact of influenza vaccine in reduction of incidence and severity of influenza-like illness

Background: Vaccination is useful for protection against seasonal influenza but has a low uptake. Evidence of a protective effect of influenza vaccine among Arab populations would be a useful tool for advocacy. Aims: To evaluate the impact of vaccine in reducing the incidence and severity of influenza-like illness among health staff of a tertiary care eye hospital in Saudi Arabia. Methods: This retrospective cohort study was conducted in 2018-2019. Hospital staff were divided into vaccinated and unvaccinated groups. Influenza-like illness episodes and their severity were compared between the groups and influenza-like illness rate before and after vaccination was reviewed in the vaccinated group. Results: The uptake of flu vaccine among 1180 health staff was 41%. There were 28 (9.3%) and 51 (17%) persons with influenza-like illness in the vaccinated (n = 300) and nonvaccinated (n = 300) groups, respectively. The nonvaccinated group had a significantly higher rate of influenza-like illness than the vaccinated group had. Vaccination, young age and absence of comorbidity were independent protectors against influenza-like illness. Conclusions: Influenza vaccine confers significant protection and reduces the incidence and severity of influenza-like illness. However, this was a retrospective review of health data; therefore, the association of vaccine with outcomes should be considered as a weak form of evidence. The low uptake of influenza vaccine in hospital staff and their dependents is a matter of concern and should be addressed by greater awareness and education. This evidence can be used to improve overall vaccine coverage.