Long-term Impact of Pneumococcal Conjugate Vaccine on Carriage

Overview

Pneumococcus is a major cause of morbidity and mortality. In 2000, a pneumococcal conjugate vaccine (PCV) was licensed for use in children and is now part of the routine childhood vaccine schedule. PCV is known to reduce invasive disease and protect against nasopharyngeal (NP) acquisition of vaccine serotype pneumococci; it also results in an increased risk of nonvaccine serotype carriage. This study proposes to assess the longterm impact of vaccine on NP carriage in a setting where there is intense antibody pressure on the ecology of the pneumococcus. A cross sectional study of pneumococcal NP colonization among American Indian children will be combined with surveillance for invasive disease in the same population. The purpose is to determine the impact of community wide PCV use on NP colonization and the relationship with invasive disease. This longterm safety issue needs to be assessed to fully evaluate the impact of vaccine on NP ecology and invasive disease.

There are four specific aims for this study: (1) to determine the overall and serotype specific prevalence and incidence of pneumococcal carriage among children and adults at high risk for carriage and disease in the era of routine pneumococcal conjugate vaccine (PCV) use compared with those measures in the same population prior to use of PCV vaccine; (2) to characterize the intrafamilial NP transmission of clones among those living with children less than 8 years of age; (3) to determine the immune correlates of protection from serotype specific pneumococcal carriage among individuals immunized and not immunized with PCV; and (4) to determine the relative invasiveness of serotypes of pneumococcus during an era of widespread PCV use and compare this to the relative invasiveness of serotypes prior to routine use of PCV.

Conditions