7-Valent pneumococcal conjugate vaccine and lower respiratory tract infections: effectiveness of a 2-dose versus 3-dose primary series.

Background: Immunogenicity studies suggest antibody responses from a 7-valent pneumococcal conjugate vaccine (PCV7) regimen consisting of 2 doses in the primary series are less immunogenic, for at least several vaccine serotypes, compared with a regimen consisting of 3 doses; evidence of effectiveness for prevention of invasive pneumococcal disease for both regimens is available but comparative data are lacking for prevention of lower respiratory tract diseases (LRTD).

Methods: We compared rates of LRTD between children who were born in 2002 and received 2 versus 3 PCV7 doses in the primary series, both before and after receipt of the booster dose, using a retrospective matched-cohort design and health insurance claims data. Two-dose and 3-dose children were matched (1:1) using propensity scoring.

Transmission-dynamic model to capture the indirect effects of infant vaccination with Prevnar (7-valent pneumococcal conjugate vaccine (PCV7)) in older populations.

We developed an age-structured, transmission-dynamic, mathematical model to quantify the direct and indirect benefits of infant PCV7 vaccination. The model simulates the acquisition of asymptomatic carriage of Streptococcus pneumoniae and the development of fatal and non-fatal invasive pneumococcal disease (IPD) among vaccinated and unvaccinated individuals aged <2, 2-4, 5-17, 18-49, 50-64, and >or=65 years old. The model was parameterized using published US surveillance data, supplemented with data from published literature.

The impact of indirect (herd) protection on the cost-effectiveness of pneumococcal conjugate vaccine.

Background: The heptavalent pneumococcal polysaccharide-protein conjugate vaccine (PCV7) confers protection against invasive pneumococcal disease (IPD) caused by serotypes that are responsible for substantial morbidity and mortality throughout the world. In 2000, the 7 serotypes covered by PCV7 accounted for 80% to 90% of serotypes isolated from the blood or cerebrospinal fluid of children aged <6 years in the United States. A previous review of the literature spanning the years 1998 to 2005 pertaining to the incidence of IPD among nonimmunized individuals in countries with universal PCV7 immunization suggested an indirect protective effect (herd protection, or community immunity) after widespread vaccination.

Indirect effects associated with widespread vaccination of infants with heptavalent pneumococcal conjugate vaccine (PCV7; Prevnar).

Prevnar (heptavalent pneumococcal conjugate vaccine; PCV7) provides protection against invasive pneumococcal disease (IPD) caused by vaccine serotypes. Indirect protection of non-immunised individuals may be the consequence of decreased transmission of vaccine serotypes, generally carried in the nasopharynx of infants and young children. This review summarises published reports of IPD incidence (1998-2005) among non-immunised individuals in countries with universal PCV7 immunisation.

Cost-effectiveness of pneumococcal conjugate vaccine: evidence from the first 5 years of use in the United States incorporating herd effects.

Background: Pneumococcal conjugate vaccine (PCV) has been in routine use in the United States for 5 years. Prior U.S.