Effect of Age on Pneumococcal Vaccine Immunogenicity in Adults Over 50 Years of Age
Many high income countries recommend immunization with pneumococcal polysaccharide vaccine and/or pneumococcal conjugate vaccines for adults over 50 years of age. WHO guidance to countries globally regarding adult immunization in the context of widespread use of infant PCV programs is needed. If PPV or PCV is recommended, the age of immunization may affect effectiveness of the vaccine. Immunogenicity is strongly associated with effectiveness and may provide guidance as to the optimal age of immunization. Striking a balance between initial vaccine responses and persistence of protection, and by implication protection, is unclear.
We undertook a systematic review of the immunogenicity of pneumococcal polysaccharide and conjugate vaccine with a focus on serotype specific IgG and functional antibody (OPA) data obtained 1-month after immunization. We also analyzed the persistence of antibody one year following immunization. While an effect of age was observed, the overall effects were small and likely not biologically meaningful.