The suboptimal efficacy of the currently available 23-valent pneumococcal vaccine in the growing population of adults >65 years old may be related to the limited immunogenicity of the vaccine polysaccharides in this group. In this study, the majority of elderly outpatients with stable chronic illnesses generated a vigorous IgG response to seven vaccine serotypes comparable to that of healthy young adults at 1, 3, and 16 months after immunization. Moreover, the quality and function of anticapsular antibodies, measured as avidity and in vitro opsonization, were comparable between elderly and young subjects over time. However, a subset (~20%) of elderly outpatients responded to fewer than two of seven serotypes tested 1 and 3 months after immunization, whereas none of the healthy young adults were such poor responders. Thus, despite the adequate mean immune responses of the elderly as a group, a substantial proportion of elderly persons may have poor responses to the currently available pneumococcal vaccine.
Bibliographical noteFunding Information:
Received 20 November 1997; revised 18 March 1998. Presented in part: International meeting of the American Thoracic Society, New Orleans, May 1996. Informed consent was obtained from patients and guidelines of the US Department of Health and Human Services and of the Institutional Review Board of the Minneapolis VA Medical Center were followed in the conduct of this research. Grant support: Department of Veterans Affairs (to J.B.R. and E.N.J.); NIH (AI-34051 to J.B.R.; AI-39445; HL-96-008 to E.N.J.). Reprints or correspondence: Dr. Jeffrey B. Rubins, Pulmonary Section (111N), VA Medical Center, One Veterans Dr., Minneapolis, MN 55417 (email@example.com). * Present address: Green Valley Medical Center, 450 W. Continental Rd., Green Valley, AZ 85614.