Serotype 6C invasive pneumococcal disease in indigenous people in north Queensland.

The seven-valent pneumococcal conjugate vaccine (7vPCV) includes serotype 6B. No invasive pneumococcal disease (IPD) caused by this serotype has occurred in Indigenous people in north Queensland since 7vPCV was made freely available to Indigenous children in the latter part of 2001.3 Although 7vPCV does not include serotype 6A, the experience in the United States of America (USA) indicates that the serotype 6B antigen included in 7vPCV provides cross-protection against serotype 6A IPD in children.4,5 However, these studies were undertaken before serotype 6C was first recognised, and therefore serotype 6C cases may have been inadvertently included in what were then considered to have been serotype 6A IPD.