112: Vaccine effectiveness of 2012 trivalent influenza vaccine for prevent ILI symptoms in healthcare workers, Satuek hospital, Buriram, August – October 2012

Conference: 
Author(s): 
E. Yodkalw1, N. Ropariram1, T. Ruangpaisarn1, Y. Aekrathok1, P. Utaravichien1, K. Tutong1, N. Kaewpitoon2, R. Rujarakul3, N. Namwichisirikul3, S. Churproong3
1 Family and community medicine, Satuek hospital, Suranaree University of Technology, Nakhonratchasima, Thailand; 2 Pathology, Suranaree University of Technology, Nakhonratchasima, Thailand; 3 Family and community medicine, Suranaree University of Technology, Nakhonratchasima, Thailand
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Background: Healthcare workers in Thailand are advised to influenza vaccination in every year. The objectives are to identify factors associated
with influenza like illness and assess vaccine effectiveness of the 2012 trivalent influenza vaccine.
Methods: For a descriptive study. We conducted active case finding to determine of Influenza-like illness among HCWs in Satuek hospital. Case definition of ILI was defined as a person who worked in Satuek Hospital and developed fever with cough and/or sore throat and/or myalgia between 1 August and 18 October 2012. Retrospective cohort study was performed to identify possible risk/protective factors and assess vaccine effectiveness. Univariate and multivariate analyses were used to estimate crude risk ratio and adjusted odds ratio with 95% confidence interval. Evaluation of vaccine effectiveness was carried out.
Results: 70 cases met to definition. Median age of cases was 33 years (IQR: 27-41 years), male to female ratio was 1:4. In univariate analysis the significant factor was 2012 trivalent influenza vaccine (crude RR = 0.46, 95%CI=0.32-0.65), BMI > 25 kg/m2 (crude RR = 1.69, 95%CI=1.15-2.47) and 2011 trivalent influenza vaccine (crude RR = 0.56, 95%CI=0.39-0.82). In multivariate analyses only 2 significant factors was 2012 trivalent influenza vaccine (adj OR = 0.29, 95%CI=0.12-0.70) and BMI > 25 kg/m2 (adj OR = 2.40, 95%CI=1.13-5.09). The vaccine effectiveness was 54.0%.
Conclusions: The 2012 trivalent influenza vaccine and BMI >25 kg/m2 was a statistically significant protective and risk factor. The vaccine effectiveness of 2012 trivalent influenza vaccine for preventing ILI was modest.

Disclosure: No conflict of interest declared