Report on the impact of pneumococcal vaccine introduction in Western Australia highlights reduction in childhood infections, but an increasing disparity between aboriginal and non-aboriginal populations, particularly in the 30-49 year age group.

Pneumococcal vaccine progress report

The changing epidemiology of invasive pneumococcal disease in aboriginal and non-aboriginal Western Australians from 1997 through 2007 and emergence of nonvaccine serotypes. Lehmann D, Willis J, Moore H et al. Clinical Infectious Diseases 2010; 50: 1477-1486.

This recently published decade-long study found that after the introduction of 7-valent pneumococcal vaccine, invasive pneumococcal disease due to 7vPCV serotypes fell in aboriginal children to a level similar to non-aboriginal children. However, there was an increasing disparity in rates between aboriginal and non-aboriginal populations, mainly due to a significant increase in invasive pneumococcal disease in aboriginal adults, particularly those between 30 and 49 years old. Non 7vPCV serotypes of Streptococcus pneumoniae increased over the study period in non-aboriginal children and in aboriginal adults.

The most likely explanation for the increase in IPD in aboriginal adults was thought to be serotype replacement, with a possible additional deleterious effect of the 23-valent pneumococcal vaccine in adults functionally immunocompromised by co-morbidities. Alternative explanations considered less likely were net fluctuations in disease due to specific virulent serotypes o changes in disease surveillance methods during the study period.  These findings were largely in line with observations in other parts of Australia.

Invasive pneumococcal disease causes an estimated 1.6 million deaths per annum worldwide, mainly in developing countries. In industrialised countries, aboriginal populations are at significantly higher risk.

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  1. RT @micrognome157: Pneumococcal vaccine progress report http://bit.ly/9NhSDX

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