Pneumococcal Vaccine: An Update

* Abbreviation: HIV = : human immunodeficiency virus Streptococcus pneumoniae is the most common cause of invasive bacterial infection in children. In addition, the organism causes 30% to 50% of cases of acute otitis media; 24 million visits to pediatricians per year in the United States are referable to this diagnosis.1 It is also responsible for a significant amount of morbidity and mortality in children and adults in the United States and in other countries. A majority of cases of invasive disease caused by S pneumoniae occur in children <2 years of age and adults 65 years of age and older.1 The current 23-valent pneumococcal vaccine has been shown to be ineffective in children <2 years old.2In addition, resistance of S pneumoniae to penicillin, cephalosporins, and other antibiotics has become a serious problem.3 These factors prompted investigations that have culminated in the development of conjugated polysaccharide-protein vaccines. These new vaccines are similar in design to the already licensed Haemophilus influenzae, type b conjugate vaccine. Widespread deployment of the conjugate H influenzae vaccine in 1987 has been followed by a major decrease in morbidity and mortality of H influenzae infection.4 In this commentary, we will review briefly pneumococcal infection and discuss the roles of current and future vaccines in the prevention of pneumococcal disease. Nasopharyngeal colonization with S pneumoniae occurs in a majority of children and is most common in children <4 years of age.2 Colonization may be followed by acute otitis media and other upper respiratory infections, as well as by pneumonia. Severe infection, including bacteremia and meningitis, also may occur with significant attendant morbidity and mortality.1 Children 6 to …