Correlation of Frailty Status with Influenza Vaccine Seroconversion and Seroprotection among Elderly Population

Introduction. Infection is still considered as a serious health threat in the world, especially among the elderly. Age was identified as one of the predictor factors for successfull vaccination. Immune response would decrease in older people. A different response in the elderly is expected from frailty and underlying immunosenescense events. This study was conducted to determine the relationship with the Frailty status after the vaccination immune response of influenza in the elderly population. Methods. This retrospective cohort study was conducted using secondary data from the parent study of elderly subjects age ≥60 years who live in the community of Posyandu lansia in Pulo Gadung Region, East Jakarta. Frailty status was stated by Frailty Index 40 Items (FI-40). The influenza vaccine evaluated was the Trivalent Inactivated Vaccine. Seroconversion defined as four fold increase hemagglutinin inhibition titre. Seroprotection defined as Hemagglutinin Inhibition titer ≥1:40. Results. There are 140 subject included in this study. Seroconversion influenza vaccine rate in frail, pre-frail, and robust group are 37.9%, 39%, 60%, respectively. Seroprotection rate in frail, pre-frail, and robust group are 80%, 92.2%, 94.8%, respectively. Relative Risk (RR) pre-frail/frail group for not seroconverted is 0.93 (CI 95% 0.72-1.02), and RR for not seroprotected is 1,7 ( CI 95% 0.5-6.2). Conclussions. There is no association between frailty status and seroconversion nor seroprotection of influenza vaccine in elderly population.