Poster, 11th International Symposium on Pneumococci and Pneumococcal Diseases, 15-19 April 2019, Melbourne, Australia.
Pneumococcal serogroup 6 traditionally comprised of serotypes 6A and 6B. While several antisera products have come to market since 2009, cross-reactivity caused by the lack of sufficiently discriminatory antisera used before this time potentially lead to the misreporting of the prevalence of the serogroup 6 serotypes. We re-typed archived carriage and invasive pneumococcal isolates using factor antisera 6b*, 6c and 6d to examine the prevalence of 6C/ 6D before vaccine introduction, and the impact of PCV10 on all serogroup 6 isolates. The inclusion of the new factors 6b* and 6d to KEMRI's serotyping panel together with the use of serotype-specific PCR improved distinction between serotypes 6A/B, 6A/C, 6B/D. 6B carriage prevalence in all age groups reduced considerably after vaccine introduction.