Evaluation of efficacy and effectiveness across the pneumococcal conjugate vaccine era

Pneumococcal conjugate vaccines (PCVs) have resulted in a dramatic reduction in vaccine-type disease in both children and adults. Several expanded PCVs have recently been approved and incorporated into immunization programs for children and adults, with numerous additional vaccine formulations in development or undergoing evaluation in clinical trials. This concise review provides an introduction to the evolving approaches to vaccine evaluation used in the decades since the initial studies of PCV7, followed by a contemporary assessment of challenges and future directions for studies of efficacy, immunogenicity, and real-world effectiveness.