Current Trend in Pneumococcal Serotype Distribution in Asia

Abstract

Asia is one of the continents in the world heavily impacted by pneumococcal diseases but yet the information on disease burden and serotype distribution remained largely unclear. The data is essentially needed to inform the burden of pneumococcal diseases as a priority public health concern among the Asian countries. The formulations of pneumococcal conjugate vaccines (PCV) included a number of prevailing serotypes in the Western world but geographical and temporal variations of vaccination effectiveness could be expected in Asia. This review focuses specifically on the most recent five years trend in serotype distributions from both invasive and non-invasive pneumococcal diseases in Asia. Other important features such as antimicrobial resistance and associated clones were also noted. All latest studies reported that complied with the scopes of this review were included and the serotyping data were extracted for comparison analysis between countries, regions, and to represent Asia as the whole. The most common serotypes detected in highest to lowest frequencies order are 19F, 14, 23F, 6B, 19A, 3, and 6A, accounted for approximate two third of the incidences. Heptavalent PCV (PCV7) is expected to cover half of the incidences with significant increment in efficacy with PCV13. East Asia, Southeast Asia, and West Asia have relatively similar serotype distributions though slight variations were observed. The more unique pattern is noted in South Asia region. Initiation of surveillance study in countries with no reporting data is needed. Continued surveillance involving nationwide or multinational collaborative networks need to be set up to enhance and standardize the reporting incidences.