Streptococcus pneumoniae causes significant morbidity and mortality. Children younger than 2 years and individuals older than 65 years experience the highest rates of pneumococcal disease. Efforts to treat pneumococcal disease have been complicated by increasing resistance to antimicrobials. Prevention efforts have included the pneumococcal polysaccharide vaccines and the pneumococcal conjugate vaccines, with use of these vaccines targeted to those at highest risk for disease. Information and background on S. pneumoniae and pneumococcal disease are provided. Vaccines targeted at this pathogen are reviewed, and the clinical trials that evaluated their safety, efficacy, and effectiveness are summarized. Also provided are recommendations for use of these vaccines.

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The number of pneumococcal isolates and the percentage of isolates with high-level penicillin resistance from cultures taken from children with OM or mastoiditis for clinical indications have decreased following PCV13 use, largely related to decreases in serotype 19A isolates.

The 7-valent pneumococcal conjugate vaccine, Prevenar, was first licensed in the United States in 2000 for the prevention of invasive pneumococcal disease (IPD) caused by the serotypes included in the vaccine. It is presently approved in more than 70 countries, and more than 100 million doses of vaccine have been distributed to date. Within 1 year of routine use in the US, incidence of vaccine-serotype IPD had fallen dramatically among children younger than 2 years, with indirect effects noted among other age groups as well. The most recent data available from the US demonstrates that vaccine-serotype IPD has declined by 94% among the age group recommended for vaccination, and indirect effects have been documented in every unvaccinated age group, including among neonates and young infants. Additionally, declines in other pneumococcal-associated respiratory tract diseases have been reported, highlighting the extended benefits of a Prevenar vaccination program. Subsequently, the vaccine has been introduced into the national immunization programs of several other countries, including Canada, Australia, and The Netherlands. While an increase in disease caused by serotypes not included in the vaccine has been observed ("replacement disease"), the overall impact of this increase has, to date, been small in comparison to the substantial reduction in overall disease burden that has resulted since Prevenar introduction.

OBJECTIVES: This study evaluated the immune response and safety profile of 13-valent pneumococcal conjugate vaccine (PCV13) in preterm infants compared with term infants.METHODS: This Phase IV, open-label, 2-arm, multicenter, parallel-group study enrolled 200 healthy infants (preterm, n = 100; term, n = 100) aged 42 to 98 days. All subjects received PCV13 at ages 2, 3, 4 (infant series), and 12 (toddler dose [TD]) months, together with routine vaccines (diphtheriatetanus-acellular pertussis, hepatitis B, inactivated poliovirus, and Haemophilus influenzae type b vaccine and meningococcal group C conjugate vaccine).RESULTS: Most subjects achieved an anticapsular immunoglobulin G (IgG) antibody concentration $0.35 mg/mL for all serotypes: .85% after the infant series (except preterm infants for serotypes 5, 6A, and 6B) and .97% after TD (except for serotype 3). Preterm infants had overall lower IgG geometric mean concentrations compared with term infants; however, geometric mean fold increases after TD were similar for all serotypes. Opsonophagocytic activity results were consistent with IgG results and titers increased after TD in both groups for all serotypes, including serotype 3. PCV13 was generally well tolerated, with similar safety profiles in all preterm subgroups.CONCLUSIONS: Immune responses were lower in preterm infants than in term infants. However, the majority of subjects in both groups achieved both pneumococcal serotype-specific IgG antibody levels after the infant series that exceeded the World Health Organization-established threshold of protection and functional antibody responses. Responses were uniformly higher after TD, reinforcing the importance of a timely booster dose. PCV13 was well tolerated regardless of gestational age.