In the late 1980s, several reports in the literature documented a very high incidence of childhood infection caused by invasive Haemophilus influenzae type b (Hib) in the Northern Territory of Australia (NT). Although these high rates were present in both the Aboriginal and non-Aboriginal communities, it was the Aboriginal children, in particular those under 12 months, who carried the highest burden of disease. Following the introduction of the vaccine into the childhood immunisation schedule in 1993 and the subsequent "catch-up" program to immunise all under five year olds in the NT, invasive Hib infection has become a rare disease in the NT.