Impact of heptavalent pneumococcal conjugate vaccine on invasive disease, antimicrobial resistance and colonization in Alaska Natives: progress towards elimination of a health disparity

We evaluated invasive pneumococcal disease (IPD), antimicrobial resistance and nasopharyngeal colonization before and after introduction of pneumococcal conjugate vaccine (PCV7) in Alaska Natives (AN), a population with high IPD rates. We obtained IPD rates from population-based surveillance. Colonization was determined from annual surveys among rural AN of all ages and from urban children. After vaccine introduction, vaccine-type IPD rates declined by 91% among AN children <2 years, by 80% among non-Natives <2 years, and by 40% for adults of all races (P < 0.001 each). IPD decreased for isolates resistant to penicillin, erythromycin and cotrimoxazole (P < 0.001 each). Vaccine-type colonization decreased among rural and urban children <5 years and among rural adults (P < 0.001 each). PCV7 vaccine has eliminated a longstanding disparity of vaccine-type IPD for AN children. Decreased vaccine-type colonization and IPD in adults demonstrate indirect vaccine effects.