Epidemiology provides a foundation for evidence based communicable disease control policy and practice. This thesis contains four discreet epidemiological studies, each utilising different methods and data sources to inform the relevant areas of communicable disease control in Australia. The first study is a descriptive epidemiological review of Q fever notifications in NSW between 2001 and 2010. Results showed that the overall incidence of Q fever has decreased significantly since the implementation of a Q fever control program in NSW in 2002. Despite an overall reduction, the epidemiology has changed with a shift of disease burden towards older age groups and a higher proportion of female cases. The findings illustrate the need for ongoing surveillance and targeting of disease control measures including vaccination. The second study investigated long term trends in the epidemiology of invasive pneumococcal disease, following the introduction of universal conjugate pneumococcal vaccination in Australia in 2005. The study demonstrates a large reduction in all invasive pneumococcal disease across young vaccinated cohorts and older nonvaccinated cohorts. The overall reduction in disease is however offset by replacement with non-vaccine serotypes, highlighting the need for improved vaccines protecting against emergent serotypes, and the need for ongoing vigilant disease surveillance. The third study reports vaccination coverage and timeliness in Aboriginal and Torres Strait Islander Australians, using data from the Australian Childhood Immunisation Register. The study identifies a gap between Aboriginal and Torres Strait Islander and non-Indigenous children with regard to vaccination coverage and timeliness. The results highlight the need for targeted strategies to improve timely uptake of vaccination amongst Aboriginal and Torres Strait Islander Australians. The final study uses disease surveillance data to identify factors associated with delayed diagnosis and treatment of tuberculosis in NSW. This study highlights the role and value of conducting enhanced epidemiological analysis of routine notifiable disease surveillance data to inform complex issues within a disease control program. The work included in this thesis highlights the value of epidemiology as applied to public health practice. By using a range of epidemiological techniques and several key public health datasets, each study demonstrates the contribution of epidemiology in informing evidence based public health policy.