Pneumococcal vaccination of older adults: conjugate or polysaccharide?

Invasive pneumococcal disease continues to be important problem for older adults. Pneumococcal polysaccharide vaccine (PPV23) has a clinical effectiveness of 43-81%, and following primary vaccination and revaccination, antibody responses last 5-10 y. Hyporesponsiveness to a second dose of vaccine has not been shown to be a significant problem. The use of pneumococcal conjugate vaccines (initially PCV7; more recently PCV13) has led to a dramatic fall in the incidence of conjugate vaccine-type invasive pneumococcal disease in children. Because PCVs are immunogenic in older adults, the question has arisen as to whether to also use PCVs in this age group. However, PCV vaccination of children has also reduced the incidence of conjugate vaccine-serotype disease in older adults, and so wherever PCVs are used in children, there is no epidemiological reason to vaccinate older adults with PCV. The cost-effectiveness of PPV for older adults has changed wherever PCVs have been used for children, and this needs to be periodically re-evaluated.