Preventing pneumococcal disease in children: A study of vaccine efficacy

How effective is the 7-valent pneumococcal conjugate vaccine in preventing invasive pneumococcal disease in young children? How do catch-up and incomplete vaccine schedules compare with the recommended schedule that has been tested in clinical trials?

Whitney and colleagues conducted a case-control study to answer these questions. They used a population- and laboratory-based surveillance system to identify 782 children (aged 3 to 59 months) with invasive pneumococcal disease. The study also included 2512 matched controls.

The 7-valent pneumococcal conjugate vaccine was effective in preventing disease in both healthy children and children with chronic illness. The effectiveness of 1 or more doses of pneumococcal vaccine against disease caused by 1 of the vaccine serotypes was 96% in healthy children and 81% in those with comorbidities.

Vaccine effectiveness was 76% against pneumococcal infections that were not susceptible to penicillin and 77% against infections that were caused by multidrug- resistant strains. Vaccination prevented disease caused by all 7 vaccine serotypes and by serotype 6A.

Vaccine effectiveness was similar for schedules with 2, 3, and 4 doses. A schedule that included 3 infant doses with a booster was more protective than one that included 3 infant doses alone.