Serotype distribution of disease-causing Streptococcus pneumoniae in Thailand: A systematic review

Background: Streptococcus pneumoniae infection is associated with a high morbidity and mortality worldwide. There are currently >98 known serotypes; the most burdensome are covered by current pneumococcal conjugate vaccines (PCVs) such as PCV10 (Synflorix (R)) and (Prevnar 13 (R)) PCV13. However, at present no PCV is available on the National Expanded Programme of Immunization (EPI) in Thailand. Methods: Here we report a systematic review of studies regarding pneumococci associated with invasive pneumococcal disease (IPD) and non-IPD in Thailand. The NCBI PubMed database and Google Scholar were used to identify relevant papers published from 1st January 1990 to 21st August 2017. The quantitative analysis was reported as the distribution of serotypes across two age groups, <= 5 and >5years old, as these were the most commonly reported. Where age was not stated, or data was combined, data were categorised as all ages. Results: The search returned 15 relevant articles. From these the five most common disease-causing serotypes, in rank order, were 6B, 23F, 14, 19A and 19F. Vaccine coverage would be 55.3% for PCV10 and 69.7% for PCV13. There was insufficient data to draw conclusions regarding non-invasive disease-causing pneumococcal serotypes. Conclusion: This review demonstrates that the serotypes which were most responsible for disease in Thailand are included in PCV10 and PCV13. Better surveillance data of IPD and non-IPD are required for monitoring vaccine effectiveness if PCV is implemented nationally. (C) 2019 Elsevier Ltd. All rights reserved.