In this thesis, I present four field research projects and a variety of epidemiological activities. I conducted this body of work at the Australian Government Department of Health, Office of Health Protection from April 2019 to October 2020 to meet the competencies required for the Master of Philosophy in Applied Epidemiology (MAE) at The Australian National University. I conducted an acute flaccid paralysis case-series review in children under 15 years of age in Australia from 2000 to 2018. I applied the new case definition for the newly termed acute flaccid myelitis and retrospectively identified 41 cases occurring most consistently from 2010 onwards. The review found that the Australian acute flaccid paralysis surveillance system was well-positioned to actively monitor this newly sustained, albeit rare syndrome in the future. I investigated an outbreak of SARS-CoV-2 among Australian passengers on the Diamond Princess cruise ship, docked in Yokohama, Japan. The outbreak showed how quickly SARS-CoV-2 could spread through a confined and susceptible population and the need for a rapid public health response to minimise onward transmission. In the post-COVID era, cruise ships will need enhanced public health planning and risk mitigation strategies to recommence operations. I evaluated COVID-19 notifications in the National Notifiable Disease Surveillance System in Australia from 22 January to 9 June 2020. I conducted semi-structured interviews with a small selection of stakeholders and analysed data quality at two-week intervals. The evaluation found a high level of representativeness and acceptability to reporting de-identified COVID-19 cases to the surveillance system. However, two-way communication between the Australian Government Department of Health and jurisdictions needed improvement. An agreed minimum dataset for national COVID-19 reporting would reduce the data collection burden on states and territories. My epidemiological study used probabilistic linkage to assess the accuracy of enrolment details in the Australian Immunisation Register. The project explored the methodology behind probabilistic data linkage using a Fellegi-Sunter approach. I matched record pairs on 11 identifiers and incorporated inexact matching and weighting by frequency. The algorithm successfully linked 54% of non-Medicare enrolled infants' vaccination records to their Medicare enrolment record. The majority of non-Medicare enrolled infants, transitioned to Medicare, and within a timeframe that would accurately capture them in the immunisation coverage calculation for one-year-olds. Lastly, I described two teaching components conducted as part of the MAE program, including their teaching rational and my lessons learnt
