Enhanced Determination of Streptococcus pneumoniae Serotypes Associated with Invasive Disease in Laos by Using a Real-Time Polymerase Chain Reaction Serotyping Assay with Cerebrospinal Fluid

A prospective hospital-based study was undertaken to define the incidence of invasive pneumococcal disease (IPD) and circulating serotypes in Laos Of 10.799 patients with hemocultures and 353 patients with cerebrospinal fluid samples. 0 21% and 5 4%, respectively, were positive for Streptococcus pneumoniae. giving a total of 35 IPD patients We developed a real-time polymerase chain reaction to detect serotypes represented in the 13-valent pneumococcal vaccine A blinded evaluation comparing serotype as defined by the Quellung reaction versus the polymerase chain reaction demonstrated 100% concordance The most frequent serotype (n = 33 patients) was 1 (n = 6), followed by serotypes 5, 6A/B/C, 14, and 23F. Serotypes represented in the 7-valent polysaccharide-protein conjugate vaccine (PCV-7) infected 39% of patients with 73% coverage for the PCV-10 and PCV-13 vaccines. Although the sample size is small, these data suggest that the PCV-7 vaccine may have relatively low efficacy in Laos Further studies are urgently needed to guide pneumococcal vaccine policy in Laos