The effect of chronic cytomegalovirus infection on pneumococcal vaccine responses.

Abstract

Immune function declines with age and has been associated with reduced vaccine responsiveness. Chronic infection with cytomegalovirus (CMV) has been proposed as a contributor to poorer responses in older adults. A pneumococcal vaccine has been recommended in the United Kingdom for those aged >65 years since 2003 to prevent pneumococcal disease. We evaluated the effect of age and CMV status on pneumococcal vaccine responses in 348 individuals aged 50-70 years. We found participant age to be associated with serotype-specific and functional antibody titers after pneumococcal vaccination, with a mean 6.2% (95% confidence interval, 2.9%-9.5%) reduction in postvaccination functional antibody titers per year. CMV status was not associated with serotype-specific immunoglobulin G concentrations or functional antibody titers after pneumococcal vaccination. However, CMV seropositivity was associated with higher levels of prevaccination functional antibody for 4 of 7 pneumococcal serotypes assessed. These data imply that CMV infection is not directly responsible for the decline in pneumococcal vaccine responses seen with age but suggest that CMV-seropositive individuals differ in their natural exposure to pneumococci or have altered mucosal immune responses after colonization with this organism.