Pneumococcal Vaccination in Adults.

Pneumococci remain the most common etiology of community-acquired pneumonia in adults, with significant attendant mortality in the elderly. With the recognition of increasing rates of drug-resistant Streptococcus pneumoniae in recent years, efforts to prevent disease through vaccination have gained greater impetus. The 23-valent pneumococcal vaccine is used widely in the United States and provides effective protection against bacteremic pneumococcal disease, particularly in the immunocompetent host. The 7-valent pneumococcal conjugate vaccine, licensed in the United States in 2000, has had a dramatic impact on pneumococcal disease in the pediatric population, and its use in children has had effects on incidence rates in nonimmunized adults as well. Future directions include efforts to improve vaccination coverage in targeted populations and the development of more immunogenic and efficacious vaccines for high-risk groups.