To B or not to B: how the hepatitis B surveillance case definition can misdirect public health actions.

Abstract: Surveillance case definitions are utilised to understand the epidemiology of communicable diseases and to inform public health actions. We report a case of hepatitis B infection that meets the case definition for newly acquired infection. However, further investigation revealed that this was most likely past resolved hepatitis B infection with subsequent reactivation secondary to immunosuppression, rather than a newly acquired infection. This case highlights the importance of thorough case and clinician interviews, in combination with detailed assessment of pathology results in collaboration with treating clinicians, to determine the most appropriate public health actions.

The Role of Local Public Health Units in Enhancing Outbreak Response in Residential Aged Care Facilities.

Local public health units offer a place-based response to disease threats impacting populations in its catchment. This place-based response can be further strengthened when local public health units (LPHUs) collaborate with local stakeholders, in particular health services, to protect the more vulnerable population. We describe the approaches taken by a newly formed LPHU in southeast metropolitan Victoria, Australia in COVID-19 outbreak management impacting residential aged care facilities (RACFs) in its catchment, throughout the different phases of the pandemic. These collaborative and flexible approaches ensured that public health actions met the demand and needs of stakeholders. Approaches included the development of prioritization and risks matrices, refining known processes such as outbreak management team membership and redefining roles of the LPHU as capacity of stakeholder evolved.

Mpox Management: A Holistic Local Response to a Global Threat.

Newly formed local public health units in Victoria have been established to support a place-based approach that tailors and delivers public health initiatives and responds to public health incidents and issues. Initially, post-establishment of these units, public health activities focused on the prevention and control of communicable diseases. In 2022, mpox emerged as a global public health threat. As case numbers rose across Australia, local public health units in Victoria were engaged by the Department of Health to support a localized response to this new threat. The South East Public Health Unit, Monash Health, developed a number of targeted initiatives to control the local spread of mpox, ranging from capacity building of health professionals to increase early diagnosis, contact tracing, facilitating vaccine delivery, and community engagement. This contributed to effective local elimination within 6 months, demonstrating how LPHUs are well placed to engage with local communities and health care providers to respond rapidly to newly emerging public health threats.

Cardiac Autonomic Impacts of Bushfire Smoke-A Prospective Panel Study.

BACKGROUND: Air pollution is associated with cardiovascular disease and mortality. Most studies have focussed on urban or traffic-related pollution, and less is known about the impacts from bushfire smoke on cardiovascular autonomic function, although it is associated with increased sudden cardiac death and mortality. We sought to investigate its instantaneous and short-term impacts on heart rate variability (HRV). METHODS: Twenty-four (24)-hour Holter electrocardiography (ECG) was repeated twice (during bushfire [Phase 1] and then clean air [Phase 2]) in 32 participants from two Australian towns (Warburton and Traralgon, Victoria) surrounding planned burning areas. This was compared with 10 control participants in another town (Maffra, Victoria) with two clean air assessments during the same periods. The primary HRV parameters assessed were those assessing overall HRV (Standard Deviation of Normal-to-Normal intervals [SDNN]), long-term HRV (Standard Deviation of the Average of Normal Sinus-to-Normal Sinus intervals for each 5-minutes [SDANN]), low frequency [LF]) and short-term HRV (Root Mean Square of Successive Differences between N-N intervals [RMSSD], High Frequency [HF], LF:HF ratio). Average concentrations of particulate matter <2.5 µm in diameter (PM2.5) were measured at fixed site monitors in each location. RESULTS: Mean PM2.5 levels were significantly elevated during bushfire exposure in Warburton (96.5±57.7 µg/m3 vs 4.0±1.9 µg/m3, p<0.001) and Traralgon (12.6±4.9 µg/m3 vs 3.4±3.1 µg/m3, p<0.001), while it remained low in the control town, Maffra, in each phase (4.3±3.2 µg/m3 and 3.9±3.6 µg/m3, p=0.70). Although SDANN remained stable in controls, the exposed cohort showed significant worsening in SDANN during bushfire smoke exposure by 9.6±25.7ms (p=0.039). In univariable analysis, smoke exposure was significantly associated with higher ΔSDNN and ΔSDANN (p=0.03, p=0.01 exposed vs control). The association remained significant in ΔSDANN after adjusting for age, sex and cigarette smoking (p=0.02) and of borderline significance in ΔSDNN (p=0.06). CONCLUSIONS: Exposure to the bushfire smoke was independently associated with reduced overall and long-term HRV. Our findings suggest that imbalance in cardiac autonomic function is a key mechanism of adverse cardiovascular effects of bushfire smoke.