Population impact of 10-valent pneumococcal conjugate vaccine (PCV10) on nasopharyngeal carriage of Streptococcus pneumoniae in Kilifi, Kenya

Poster, 11th International Symposium on Pneumococci and Pneumococcal Diseases, 15-19 April 2018, Melbourne, Australia



To assess the impact of introduction of PCV10 on nasopharyngeal (NP) carriage of S. pneumoniae, cross-sectional surveys of age-stratified randomly selected KHDSS residents (n=~500 per year) were performed annually in June - October in 2009-2010 (pre-PCV10) and 2011-2017 (post-PCV10). Adjusted prevalence ratios of NP carriage were calculated using log-binomial regression, with adjustment for confounding variables that were significant at p<0.1. A rapid, significant reduction in VT carriage at a population level was observed after introduction of PCV10 into the routine infant vaccination schedule, accompanied by a catch-up campaign. These findings suggest that PCV use in Africa will have substantial effects on invasive pneumococcal disease (IPD). Low-level persistent VT carriage may serve as a reservoir for transmission and disease in un- and under-vaccinated members of the population. An additional catch-up campaign among older children, or implementation of a booster dose may be needed to drive carriage down to levels seen in mature programs in other parts of the world (i.e., VT carriage <1-2%).