Serotype prevalence of Streptococcus pneumoniae in Malaysia - the need for carriage studies

Pneumococcal disease, caused by the bacterium Streptococcus pneumoniae, is a major burden to global health. Although the World Health Organisation (WHO) strongly recommends the inclusion of pneumococcal conjugate vaccines in national immunisation programmes (NIP's) worldwide, this has not occurred in many countries in the WHO South East Asia and Western Pacific regions - particularly longstanding middle-income countries. It is widely accepted that carriage of S. pneumoniae is a precursor to developing any pneumococcal disease. The reduction in pneumococcal disease from vaccine serotypes (VT) following widespread implementation of the pneumococcal conjugate vaccine (PCV) is believed to be through the direct immunogenic protective effect of immunised individuals as well as indirectly through herd immunity diminishing the incidence of disease in nonimmunised individuals. In Malaysia, pneumococcal disease is not included in national surveillance programmes and although PCVs have been licensed, they have not been included in the NIP. Hence, the vaccine is only available privately and the majority of the population is not able to afford it. There is an urgent need to develop surveillance programmes in Malaysia to include pneumococcal serotype data from carriage and invasive disease so that it may help guide national vaccine policy prior to a decision being taken on the inclusion of PCVs in the NIP.