POTENTIAL INTERVENTIONS FOR THE PREVENTION OF CHILDHOOD PNEUMONIA - GEOGRAPHIC AND TEMPORAL DIFFERENCES IN SEROTYPE AND SEROGROUP DISTRIBUTION OF STERILE SITE PNEUMOCOCCAL ISOLATES FROM CHILDREN - IMPLICATIONSFOR VACCINE STRATEGIES

Streptococcus pneumoniae is a leading cause of fatal bacterial pneumon ia in young children. Pneumococcal polysaccharide vaccines have not be en promoted for use in young children because many constituent serotyp es are not immunogenic in children < 2 years old. Conjugating pneumoco ccal polysaccharide epitopes to a protein carrier would likely increas e vaccine immunogenicity in children, We reviewed published and unpubl ished pneumococcal serotype and serogroup data from 16 countries on 6 continents to determine geographic and temporal differences in serotyp e and serogroup distribution of sterile site pneumococcal isolates amo ng children and to estimate coverage of proposed and potential pneumoc occal conjugate vaccine formulas, The most common pneumococcal serotyp es or groups from developed countries were, in descending order, 14, 6 , 19, 18, 9, 23, 7, 4, 1 and 15. In developing countries the order was 6, 14, 8, 5, 1, 19, 9, 23, 18, 15 and 7. Development of customized he ptavalent vaccine formulas, one for use in all developed countries and one for use in all developing countries, would not provide substantia lly better coverage against invasive pneumococcal disease than two cur rently proposed heptavalent formulas, An optimal nanovalent vaccine fo r global use would include serotypes 1, 5, 6B, 7F, 9V, 14, 18C, 19F an d 23F. Geographic and temporal variation in pneumococcal serotypes dem onstrates the need for a species-wide pneumococcal vaccine.