Effect of Vaccination on Influenza Infection Rate on KSA

Influenza is an acute respiratory disease characterized in its full form by the sudden onset of high fever, coryza, cough, headache, malaise, and inflammation of the upper respiratory tree and trachea. In most cases, pneumonic involvement is not clinically prominent. Aim of study: this Review, we examine the influenza virus infection in cross section study in Riyadh city KSA, This knowledge is used for risk assessments for future, and study effect of influenza vaccine and its implication against influenza virus infection rate STUDY METHODS: A cluster randomized trial involving 1271 children and adolescents and adult, age group between 36 months to 60 years who attend for SMC (Specialized medical center hospital) hospital in ER from January 1 2018, and ended December 31, 2018. History was taken for received vaccine or not, and risk factor diseases (Bronchial Asthma, Diabetics, Heart disease, pneumonia, Immunocompromised). NASOPHARNGEAL swab for: Diagnostic tests: rapid antigen testing, reverse transcription polymerase chain reaction (RT-PCR), and rapid molecular assays, and Follow-up for outcome in infected cases Results: the study revealed that 361of 1271 (28.4%) had influenza, 89 patient had H1N1 (7%), 128 patients had influenza A (10.07%) & 144 patients had influenza B (11.32%), one case had H1N1 and Influnza B Detected, 61% had received vaccination., Among 361 diseased cases 137 receive vaccine (37.9%), outcome of case did not need hospital admission, complete recovery for a protective effectiveness of 61% (95% confidence interval [P =.03). overall protective effectiveness of influenza vaccine was 59.3% in children and 66.5% in adult so over all protection 63%, recommendation Routine annual influenza vaccination is recommended for all persons age 6 months and older