Invasive pneumococcal disease in Western Australia: emergence of serotype 19A

To the Editor: The pattern of invasive pneumococcal disease (IPD) in Western Australia varies from that described in northern Queensland in a recent article by Hanna and colleagues.1 Their study showed a decline in IPD caused by serotypes included in the 7-valent pneumococcal conjugate vaccine (7vPCV) among Indigenous children and adults after the introduction of the vaccine in north Queensland. Over the same period, there was an increase among Indigenous adults in cases of IPD caused by serotypes not covered by the vaccine. However, the authors reported that there had been no increase in IPD caused by serotype 19A, a non-7vPCV serotype that has been increasingly predominant in other populations.2,3 In contrast to the disease pattern in north Queensland, serotype 19A has become the predominant disease-causing serotype in Western Australia, particularly among non-Indigenous people.