Assessing the effect of pneumococcal conjugate vaccines

Since 2000, more than 70 countries have introduced pneumococcal conjugate vaccines. Ecological studies—ie, studies that track disease trends over time in relation to the timing of interventions such as introduction of pneumococcal vaccines—have documented reductions in invasive pneumococcal disease, otitis media, and pneumococcal pneumonia after initiation of routine vaccination of infants with a seven-valent pneumococcal conjugate vaccine (PCV7) in the USA and elsewhere.