Influenza vaccine and cardiac protection: a study from a tertiary care center.

Patients with heart disease (HD) are at increased risk of developing cardiac complications if they acquire the influenza virus. The objective of this study was to determine whether the influenza vaccine has a primary role in preventing newly diagnosed HD in patients who have no history of HD and who were being followed up at the American University of Beirut Medical Center (AUBMC). The study is a retrospective cohort, with 2-years follow up, which was conducted using electronic medical records between the years of 2011-2013 in a tertiary care center. All patients 60 years and older (n = 698) who have taken the flu vaccine were randomly selected from the University Health Service records (UHS) and compared to a group who has not taken the flu vaccine during the same period. The odds of developing HD among vaccinated people with cofactors are 0.97 times the odds of that among non-vaccinated. This odds ratio is not significantly different than that of people vaccinated without cofactors (OR = 1.74). The occurrence of HD in the presence of vaccination revealed a non-significant decrease trend with the increase in a number of risk factors (OR = 1.61 vs 0.97). Our results suggest that there was a non-significant difference between the effect of the vaccine for influenza on patients who had cofactors for HD and those who had not. Similarly, the effect of vaccine showed a non-significant increase in protective effect as the number of comorbidities increase. The potential effects of the vaccine may be related to the protection against flu.