Applied Epidemiology of Vaccine Preventable Diseases and Outbreaks in New South Wales
Creators: name: Thompson, Craig K
Publisher: name: The Australian National University
Year: 2016
Subjects: Applied Epidemiology, Vaccine Preventable Diseases, Outbreaks, Salmonella Agona, invasive pneumococcal disease, hepatitis A, Indigenous, data linkage, AusVaxSafety, surveillance, evaluation

description: The National Centre for Immunisation Research and Surveillance (NCIRS) is located within the Kids Research Institute (KRI) at Westmead Children’s Hospital. It is somewhat hidden away from the children’s hospital, and no easier to navigate internally once you find the building on your first day. During my two years there, I was part of the Coverage, Evaluation and Surveillance (CES) Program Stream, which met monthly to discuss achievements and deliverables of the group. As an active member, I was encouraged to keep the group up to date on my progress throughout my MAE journey. The Western Sydney Public Health Unit (WSPHU) is located at Cumberland Hospital adjacent to Westmead Children’s Hospital. I spent two weeks at the PHU, observing and assisting wherever possible. I helped with a measles outbreak, including contract tracing, interviewing people, maintaining clinical line lists, informing high-risk people of a measles-clinic and assisting medical staff during the running of the measles-clinic. During this emergency response, all high-risk people (including pregnant mothers and newborn babies) were contacted and provided with appropriate prophylaxis to prevent illness. During my time there, I was also very fortunate to lead a Salmonella outbreak investigation (Chapter 3). The Communicable Diseases Branch (CDB) is located in the Ministry of Health building in North Sydney. I spent almost four months there conducting the epidemiological investigation (Chapter 4). During my time at the CDB, I attended staff meetings, afternoon debriefs, surveillance meetings and an in-house emergency response workshop. I was also very fortunate to be funded to attend the OzFoodNet whole genome workshop in Melbourne. I also assisted with two Legionella outbreaks, where I helped to maintain line-lists and the Sit-Rep, and attended the afternoon meetings, where I was asked to take, transcribe and distribute minutes of meeting from time to time. I truly enjoyed my experience at the CDB, NSW Health. 1.2 Summary of my public health experience 1.2.1 Analysis of a public health dataset (Chapter 2) In November 2005, hepatitis A vaccine was funded under the Australian National Immunisation Program for Indigenous children aged 12-24 months in the targeted jurisdictions of Queensland, South Australia, Western Australia and the Northern Territory. I reviewed the epidemiology of hepatitis A from 2000-2014 using data from the Australian National Notifiable Diseases Surveillance System, the National Hospital Morbidity Database, and Australian Bureau of Statistics causes-of-death data. Overall, the national hepatitis A immunisation program has had a significant impact in the targeted population with relatively modest vaccine coverage, with evidence of substantial herd protection effects. 1.2.2 Outbreak Investigation (Chapter 3) During May 2015, an increase in Salmonella Agona cases was reported from western Sydney, Australia. I present the public health actions used to investigate and control this increase. A descriptive case-series investigation was conducted. Six outbreak cases were identified; all had consumed cooked tuna sushi rolls purchased within a western Sydney shopping complex. Onset of illness for outbreak cases occurred between 7 April and 24 May 2015. Salmonella was isolated from food samples collected from the implicated premise and a prohibition order issued. No further cases were identified following this action. In addition, this outbreak investigation also demonstrated genomics-enhanced public health action, where whole genome sequencing significantly enhanced the resolution of the epidemiological investigation. 1.2.3 Epidemiological investigation (Chapter 4) Among adults, pneumococcal pneumonia causes significant mortality and morbidity. While the funding of polysaccharide pneumococcal vaccines have reduced the incidence of invasive pneumococcal disease (IPD) in older people, uncertainty remains regarding their effectiveness against reducing the hospitalisation rate due to community acquired pneumonia. In this study I use linked-data to document that approximately one in seven hospital admissions coded for pneumococcal pneumonia in older people of NSW were due to invasive pneumococcal disease. The remaining six hospital admissions were presumptive non-invasive pneumococcal pneumonia cases. I also documented significant declines in the rate and severity of hospitalisations over time due to presumptive non-invasive pneumococcal pneumonia. The pneumococcal polysaccharide vaccine that was used for adults has not been consistently shown to be effective against non-invasive pneumococcal pneumonia hospitalisations, while the conjugate vaccine used in the children program has provided substantial indirect protection against IPD to adults. The results presented here could impact on cost-effectiveness of pneumococcal vaccine programs in Australia. 1.2.4 Evaluation of a surveillance system (Chapter 5) The AusVaxSafety enhanced active surveillance system was established in 2014 and has two main functions. Firstly, to gather near real-time data of AEFI following seasonal influenza vaccination of children aged between six months and five; secondly, to collate, interpret and disseminate these results in near real-time to stakeholders and the public. AusVaxSafety was evaluated to assess the usefulness of the information collected; identify strengths and limitations; and provide feedback to stakeholders regarding recommendations to the system. During the 2015 influenza season, the AusVaxSafety successfully demonstrated, in real-time, that influenza vaccines registered for used in children aged six months to five years were safe, well tolerated, and that the AEFIs experienced were within expected ranges.