Reason Behind the Poor Rate of Flu Vaccine Response in the Elderly

Byron's Comments:

The lack of an efficient immune response means that the heads up given by the flu vaccine is of little value.

Study Title:

Role of humoral and cell-mediated immunity in protection from influenza disease after immunization of healthy elderly.

Study Abstract:

While influenza immunization significantly reduces the risk of pneumonia and associated deaths, vaccination of elderly only affords 30-50% protection against influenza disease. The purpose of this study was to: (1) evaluate the consistency of immune responses across multiple years in young and elderly; (2) determine the contribution of antibody and cell-mediated responses in protection after immunization with influenza vaccine. Independently living healthy elderly (>200/year; mean age 78.8-80.6/year) were recruited yearly in this four year study. The results clearly demonstrate: (1) both young and elderly consistently produced significant antibody and T cell proliferative responses to influenza vaccine upon yearly immunization; however, both responses of elderly were significantly and consistently lower than young. (2) Percentages of both young and elderly demonstrating protective titers (i.e. HI>/=40) increased post-immunization each year, but were consistently higher in young compared to elderly. (3) The risk of developing influenza disease after immunization was highest among elderly demonstrating neither antibody nor cell-mediated responses. Importantly, the risk of influenza disease was comparable in elderly demonstrating a cell-mediated response alone, an antibody response alone, or both cell-mediated and antibody responses. This suggests that cell-mediated responses play a significant role in protection in at least a subset of elderly from influenza disease after immunization.

Study Information:

Role of humoral and cell-mediated immunity in protection from influenza disease after immunization of healthy elderly. Role of humoral and cell-mediated immunity in protection from influenza disease after immunization of healthy elderly. Exp Gerontol. 2002 January 37(2-3):427-39.
Department of Microbiology and Immunology, MCP Hahnemann University School of Medicine and Public Health, 2900 Queen Lane, Philadelphia, PA 19129, USA