Effect of Influenza Vaccination on Mortality and Risk of Hospitalization in Patients With Heart Failure: A Systematic Review and Meta-analysis. - Poudel, Sanjay; Shehadeh, Fadi; Zacharioudakis, Ioannis M; Tansarli, Giannoula S; Zervou, Fainareti N; Kalligeros, Markos; Aalst, Robertus van; Chit, Ayman; Mylonakis, Eleftherios (Open Forum Infectious Diseases, 2019)