COVID-19 epidemic modelling for policy decision support in Victoria, Australia 2020-2021.

BACKGROUND: Policy responses to COVID-19 in Victoria, Australia over 2020-2021 have been supported by evidence generated through mathematical modelling. This study describes the design, key findings, and process for policy translation of a series of modelling studies conducted for the Victorian Department of Health COVID-19 response team during this period. METHODS: An agent-based model, Covasim, was used to simulate the impact of policy interventions on COVID-19 outbreaks and epidemic waves. The model was continually adapted to enable scenario analysis of settings or policies being considered at the time (e.g. elimination of community transmission versus disease control). Model scenarios were co-designed with government, to fill evidence gaps prior to key decisions. RESULTS: Understanding outbreak risk following incursions was critical to eliminating community COVID-19 transmission. Analyses showed risk depended on whether the first detected case was the index case, a primary contact of the index case, or a 'mystery case'. There were benefits of early lockdown on first case detection and gradual easing of restrictions to minimise resurgence risk from undetected cases. As vaccination coverage increased and the focus shifted to controlling rather than eliminating community transmission, understanding health system demand was critical. Analyses showed that vaccines alone could not protect health systems and need to be complemented with other public health measures. CONCLUSIONS: Model evidence offered the greatest value when decisions needed to be made pre-emptively, or for questions that could not be answered with empiric data and data analysis alone. Co-designing scenarios with policy-makers ensured relevance and increased policy translation.

Clinicians' and Users' Views and Experiences of a Tele-Mental Health Service Implemented Alongside the Public Mental Health System during the COVID-19 Pandemic.

A tele-mental health model called Head to Health was implemented in the state of Victoria, Australia to address the crisis caused by the COVID-19 pandemic. It was a free centralized intake service that adopted a targeted approach with several novel elements, such as stepped care and telehealth. This study examines the views and experiences of clinicians and service users of the tele-mental health service in the Gippsland region of Victoria during the COVID-19 pandemic. Data from clinicians were obtained via an online 10-item open-ended survey instrument and from service users through semi-structured interviews. Data were obtained from 66 participants, including 47 clinician surveys and 19 service user interviews. Six categories emerged from the data. They were: 'Conditions where use of tele-mental health is appropriate', 'Conditions where tele-mental health may not be useful', 'Advantages of tele-mental health', 'Challenges in using tele-mental health', 'Client outcomes with tele-mental health', and 'Recommendations for future use'. This is one of a few studies where clinicians' and service users' views and experiences have been explored together to provide a nuanced understanding of perspectives on the efficacy of tele-mental health when it was implemented alongside public mental health services.

Practical infection control training for Victoria's aged care workforce at the time of COVID-19 pandemic: a community case study.

The need to improve career development and training for residential aged care workers in Australia to achieve required essential competencies, including infection prevention and control competencies, has been repeatedly highlighted. In Australia long-term care settings for older adults are known as residential aged care facilities (RACFs). The COVID-19 pandemic has brought to light the lack of preparedness of the aged care sector to respond to emergencies, and the urgent need to improve the infection prevention and control training in residential aged care facilities. The government in the Australian State of Victoria allocated funds to support older Australians in RACFs, including funds toward infection prevention and control training of RACF staff. The School of Nursing and Midwifery at Monash University addressed some of these challenges in delivering an education program on effective infection prevention and control practices to the RACF workforce in Victoria, Australia. This was the largest state-funded program delivered to RACF workers to date in the State of Victoria. The aim of this paper is to provide a community case study, where we share our experience of program planning and implementation during early stages of the COVID-19 pandemic and lessons learned.

An unbroken ring of the chain of survival.

This is a commentary on the study conducted by Kennedy et al. from Victoria, Australia, that analyzed the cohort of all adult EMS-witnessed out-of-hospital cardiac arrest (OHCA) patients in the region and compared patients treated during the COVID-19 period to a historical comparator period. The commentary summarizes the study findings and discusses the importance of the study in the context of the chain of survival and changes in airway management for OHCA patients during the COVID-19 pandemic.

Mental health and wellbeing of health and aged care workers in Australia, May 2021 - June 2022: a longitudinal cohort study.

OBJECTIVES: To assess the mental health and wellbeing of health and aged care workers in Australia during the second and third years of the coronavirus disease 2019 (COVID-19) pandemic, overall and by occupation group. DESIGN, SETTING, PARTICIPANTS: Longitudinal cohort study of health and aged care workers (ambulance, hospitals, primary care, residential aged care) in Victoria: May-July 2021 (survey 1), October-December 2021 (survey 2), and May-June 2022 (survey 3). MAIN OUTCOME MEASURES: Proportions of respondents (adjusted for age, gender, socio-economic status) reporting moderate to severe symptoms of depression (Patient Health Questionnaire-9, PHQ-9), anxiety (Generalized Anxiety Disorder scale, GAD-7), or post-traumatic stress (Impact of Event Scale-6, IES-6), burnout (abbreviated Maslach Burnout Inventory, aMBI), or high optimism (10-point visual analogue scale); mean scores (adjusted for age, gender, socio-economic status) for wellbeing (Personal Wellbeing Index-Adult, PWI-A) and resilience (Connor Davidson Resilience Scale 2, CD-RISC-2). RESULTS: A total of 1667 people responded to at least one survey (survey 1, 989; survey 2, 1153; survey 3, 993; response rate, 3.3%). Overall, 1211 survey responses were from women (72.6%); most respondents were hospital workers (1289, 77.3%) or ambulance staff (315, 18.9%). The adjusted proportions of respondents who reported moderate to severe symptoms of depression (survey 1, 16.4%; survey 2, 22.6%; survey 3, 19.2%), anxiety (survey 1, 8.8%; survey 2, 16.0%; survey 3, 11.0%), or post-traumatic stress (survey 1, 14.6%; survey 2, 35.1%; survey 3, 14.9%) were each largest for survey 2. The adjusted proportions of participants who reported moderate to severe symptoms of burnout were higher in surveys 2 and 3 than in survey 1, and the proportions who reported high optimism were smaller in surveys 2 and 3 than in survey 1. Adjusted mean scores for wellbeing and resilience were similar at surveys 2 and 3 and lower than at survey 1. The magnitude but not the patterns of change differed by occupation group. CONCLUSION: Burnout was more frequently reported and mean wellbeing and resilience scores were lower in mid-2022 than in mid-2021 for Victorian health and aged care workers who participated in our study. Evidence-based mental health and wellbeing programs for workers in health care organisations are needed. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry: ACTRN12621000533897 (observational study; retrospective).

A tailored COVID-19 vaccination pathway for children 5-11 years in Victoria, Australia.

BACKGROUND: Procedural anxiety was anticipated in children 5-11 years during the COVID-19 vaccine rollout in Victoria, Australia, as children in this age group receive few routine vaccines. Therefore, the Victorian state government designed a tailored, child-friendly vaccine program. This study aimed to assess parental satisfaction with elements of the bespoke vaccination pathway. METHODS: The Victorian government and state-run vaccination hubs in Victoria facilitated an online immunisation plan to help parents identify their child's support needs, and utilised experienced paediatric staff and additional supports for children with severe needle distress and/or disability. All parents/guardians of children 5-11 years who received a COVID-19 vaccine in a vaccination hub were sent a 16-item feedback survey via text message. RESULTS: Between 9 February and 31 May 2022 there were 9203 responses; 865 children (9.4%) had a first language other than English, 499 (5.4%) had a disability or special needs, and 142 (1.5%) were Aboriginal or Torres Strait Islander. Most parents (94.4%; 8687/9203) rated their satisfaction with the program as very good or excellent. The immunisation plan was used by 13.5% (1244/9203) of respondents, with usage more common for Aboriginal or Torres Strait Islander children (26.1%; 23/88) or families with a first language other than English (23.5%; 42/179). The child-friendly staff (88.5%, 255/288) and themed environment (66.3%, 191/288) were the most valued measures for vaccination. Additional support measures were required by 1.6% (150/9203) of children in the general population and 7.9%, (17/261) of children with a disability and/or special needs. CONCLUSION: A tailored COVID-19 vaccination program for children 5-11 years, with additional support for children with severe needle distress and/or disability, had high parental satisfaction. This model could be utilised for COVID-19 vaccination in pre-school children and for routine childhood vaccination programs to provide optimal support to children and their families.

Trends in testing of sexually transmissible infections (STIs), sexual health knowledge and behaviours, and pornography use in cross-sectional samples of young people in Victoria, Australia, 2015-21.

BACKGROUND: Sexually transmissible infections (STI) are prevalent and increasing among young Australians. This study examined trends in STI testing, sexual health knowledge/behaviours, and pornography use in young people aged 15- 29years in Victoria, Australia between 2015 and 2021. METHODS: Seven online cross-sectional surveys were conducted in a convenience sample of young people, recruiting a total of 7014 participants (67% female). Logistic regression analyses determined trends over time in binary outcomes. RESULTS: There was a decrease in reports of lifetime vaginal sex over time, while lifetime anal sex remained stable. Among those who had ever had vaginal sex, results showed an increase in the use of long-acting reversible contraceptives on the last occasion of vaginal sex. There was no change in STI testing or condom use with all partner types. Knowledge of STIs and sexual health changed over time: the proportion knowing that chlamydia can make women infertile decreased over time, while knowledge that taking the pill does not reduce fertility increased. There was no change in pornography use after adjusting for demographic variables. CONCLUSIONS: Although uptake of long-acting contraceptives increased, STI knowledge and testing, as well as consistent condom use, remained low. Public health interventions should continue to address these critical components of STI prevention.

Factors Impacting Readiness to Perform Secondary Population-Based Triage During the Second Wave of COVID-19 in Victoria, Australia: Pilot Study.

OBJECTIVE: Pandemics generate such a significant demand for care that traditional triage methods can become saturated. Secondary population-based triage (S-PBT) overcomes this limitation. Although the coronavirus disease (COVID-19) pandemic forced S-PBT into operation internationally during the first year of the pandemic, Australian doctors were spared this responsibility. However, the second wave of COVID-19 provides an opportunity to explore the lived experience of preparing for S-PBT within the Australian context.The aim of this study is to explore the lived experience of preparing to operationalize S-PBT to allocate critical care resources during Australia's second wave of COVID-19 in 2020. METHODS: Intensivists and emergency physicians working during the second Victorian COVID-19 surge were recruited by purposive non-random sampling. Semi-structured interviews were hosted remotely, recorded, transcribed, and coded to facilitate a qualitative phenomenological analysis. RESULTS: Six interviews were conducted with an equal mix of intensivists and emergency doctors. Preliminary findings from a thematic analysis revealed 4 themes: (1) threat of resources running; (2) informed decision requiring information; (3) making decisions as we always do; and (4) a great burden to carry. CONCLUSION: This is the first description of this novel phenomenon within Australia and, in doing so, it identified a lack of preparedness to operationalize S-PBT during the second wave of COVID-19 in Australia.

The effect of the COVID-19 pandemic on the incidence and survival outcomes of EMS-witnessed out-of-hospital cardiac arrest.

AIM: We sought to examine the impact of the COVID-19 pandemic on the incidence and survival outcomes of emergency medical service (EMS)-witnessed out-of-hospital cardiac arrest (OHCA) in Victoria, Australia. METHODS: We performed an interrupted time-series analysis of adult EMS-witnessed OHCA patients of medical aetiology. Patients treated during the COVID-19 period (1st March 2020 to 31st December 2021) were compared to a historical comparator period (1st January 2012 and 28th February 2020). Multivariable poisson and logistic regression models were used to examine changes in incidence and survival outcomes during the COVID-19 pandemic, respectively. RESULTS: We included 5,034 patients, 3,976 (79.0%) in the comparator period and 1,058 (21.0%) in the COVID-19 period. Patients in the COVID-19 period had longer EMS response times, fewer public location arrests and were significantly more likely to receive mechanical CPR and laryngeal mask airways compared to the historical period (all p < 0.05). There were no significant differences in the incidence of EMS-witnessed OHCA between the comparator and COVID-19 periods (incidence rate ratio 1.06, 95% CI: 0.97-1.17, p = 0.19). Also, there was no difference in the risk-adjusted odds of survival to hospital discharge for EMS-witnessed OHCA occurring during COVID-19 period compared to the comparator period (adjusted odd ratio 1.02, 95% CI: 0.74-1.42; p = 0.90). CONCLUSION: Unlike the reported findings in non-EMS-witnessed OHCA populations, changes during the COVID-19 pandemic did not influence incidence or survival outcomes in EMS-witnessed OHCA. This may suggest that changes in clinical practice that sought to limit the use of aerosol generating procedures did not influence outcomes in these patients.

The impacts of COVID-19 measures on drug markets and drug use among a cohort of people who use methamphetamine in Victoria, Australia.

BACKGROUND AND AIMS: Few studies of the impacts of the coronavirus disease 2019 (COVID-19) public health measures on drug markets and drug use patterns have used longitudinal data. We aimed to examine whether COVID-19 measures were associated with increases in methamphetamine price, decreases in methamphetamine use frequency and subsequent changes in secondary outcomes of other drug use frequency in metropolitan Melbourne and regional Victoria. DESIGN: Longitudinal analysis framework was used from a longitudinal cohort of people who use methamphetamine. SETTING: Victoria state, Australia. PARTICIPANTS: One hundred eighty-five VMAX study participants who reported a methamphetamine purchase after the onset of the pandemic were used for the price paid analysis. Methamphetamine or other drug use frequency analysis was performed using 277 participants who used methamphetamine during the pandemic or in the year before the pandemic. MEASUREMENTS: Price paid per gram of methamphetamine derived from the most recent purchase price and most recent purchase quantity. Frequency of methamphetamine and other drug use measured as the average number of days per week used in the last month. FINDINGS: Compared with pre-COVID-19 period, methamphetamine prices increased by AUD351.63 (P value <0.001) and by AUD456.51 (P value <0.001) in Melbourne and regional Victoria, respectively, during the period in which the most intense public health measures were implemented in Victoria. Although prices decreased after harder restrictions were lifted (by AUD232.84, P value <0.001 and AUD263.68, P value <0.001, in Melbourne and regional Victoria, respectively), they remained higher than pre-COVID-19 levels. A complementary 76% decrease was observed in relation to methamphetamine use frequency in regional Victoria (P value = 0.006) that was not offset by any changes in the frequency of use of other drugs such as alcohol, tobacco or other illicit drugs. CONCLUSION: COVID-19 public health measures in Victoria state, Australia, appear to have been associated with major price changes in the methamphetamine market and decreased frequency of use of the drug.

Shoulder injury following COVID-19 vaccine administration: a case series and proposed diagnostic algorithm.

BACKGROUND: Shoulder Injury Related to Vaccine Administration (SIRVA) is a preventable adverse event following incorrect vaccine administration, which can result in significant long-term morbidity. There has been a notable surge in reported cases of SIRVA as a rapid national population-based COVID-19 immunization program has been rolled out across Australia. METHODS: Surveillance of Adverse Events Following Vaccination in the Community (SAEFVIC) in Victoria identified 221 suspected cases of SIRVA following the commencement of the COVID-19 vaccination program, reported between February 2021 and February 2022. This review describes the clinical features and outcomes of SIRVA in this population. Additionally, a suggested diagnostic algorithm is proposed, in order to facilitate early recognition and management of SIRVA. RESULTS: 151 cases were confirmed as SIRVA, with 49.0% having received vaccines at state vaccination centers. 75.5% were suspected incorrect administration site, with most patients experiencing shoulder pain and restricted movement within 24 hours of vaccination, lasting on average 3 months. CONCLUSION: Improved awareness and education regarding SIRVA is imperative in a pandemic vaccine roll-out. The development of a structured framework for evaluating and managing suspected SIRVA will aid in timely diagnosis and treatment, essential to mitigate potential long-term complications.

Recruiting and retaining community-based participants in a COVID-19 longitudinal cohort and social networks study: lessons from Victoria, Australia.

BACKGROUND: Longitudinal studies are critical to informing evolving responses to COVID-19 but can be hampered by attrition bias, which undermines their reliability for guiding policy and practice. We describe recruitment and retention in the Optimise Study, a longitudinal cohort and social networks study that aimed to inform public health and policy responses to COVID-19. METHODS: Optimise recruited adults residing in Victoria, Australia September 01 2020-September 30 2021. High-frequency follow-up data collection included nominating social networks for study participation and completing a follow-up survey and four follow-up diaries each month, plus additional surveys if they tested positive for COVID-19 or were a close contact. This study compared number recruited to a-priori targets as of September 302,021, retention as of December 31 2021, comparing participants retained and not retained, and follow-up survey and diary completion October 2020-December 2021. Retained participants completed a follow-up survey or diary in each of the final three-months of their follow-up time. Attrition was defined by the number of participants not retained, divided by the number who completed a baseline survey by September 302,021. Survey completion was calculated as the proportion of follow-up surveys or diaries sent to participants that were completed between October 2020-December 2021. RESULTS: At September 302,021, 663 participants were recruited and at December 312,021, 563 were retained giving an overall attrition of 15% (n = 100/663). Among the 563 retained, survey completion was 90% (n = 19,354/21,524) for follow-up diaries and 89% (n = 4936/5560) for monthly follow-up surveys. Compared to participants not retained, those retained were older (t-test, p <  0.001), and more likely to be female (χ2, p = 0.001), and tertiary educated (χ2, p = 0.018). CONCLUSION: High levels of study retention and survey completion demonstrate a willingness to participate in a complex, longitudinal cohort study with high participant burden during a global pandemic. We believe comprehensive follow-up strategies, frequent dissemination of study findings to participants, and unique data collection systems have contributed to high levels of study retention.

Pediatric Hepatitis and Respiratory Viruses: A Spatiotemporal Ecologic Analysis.

INTRODUCTION: Beginning in early 2022, clusters of severe pediatric hepatitis were reported in Europe and the United States. To date, no cause has been identified although human adenovirus 41 has been proposed in a proportion of cases. We examined population data >11 years for hepatitis clusters in Victoria, Australia, and whether any were spatiotemporally associated with community transmission of common respiratory viruses. METHODS: We used SaTScan to analyze for clusters of pediatric hepatitis and respiratory adenoviruses in Victoria. Negative binomial regression analysis was performed to determine any associations between hepatitis and respiratory viruses across Victoria between July 1, 2011, and June 30, 2022. RESULTS: A number of positive associations were observed in Victoria between pediatric hepatitis clusters and respiratory viruses in our spatiotemporal analysis. A positive association was not found with respiratory adenoviruses or SARS-CoV-2. Increased hepatitis clusters were observed in 2021 and 2022 as noted internationally. CONCLUSION: The current hepatitis outbreak is novel and, although respiratory viruses are broadly associated with hepatitis, SARS-CoV-2 and respiratory adenoviruses are unlikely to be related.

The causal effect of being born extremely preterm or extremely low birthweight on neurodevelopment and social-emotional development at 2 years.

AIM: To assess the causal effect of being born extremely preterm (EP; <28 weeks' gestation) or extremely low birthweight (ELBW; <1000 g), compared with being born at term, on neurodevelopment and social-emotional development at 2 years' corrected age. METHODS: Prospective geographical cohort study of children born EP/ELBW over 12 months in 2016 from Victoria, Australia, and term-born controls. Children were assessed at 2 years' corrected age with the Bayley Scales of Infant and Toddler Development-3rd edition and the Infant-Toddler Social and Emotional Assessment. Delay was defined as <-1 standard deviation relative to the mean of controls. The estimand of interest was the mean difference/odds ratio (OR) between the EP/ELBW and control groups estimated using linear/logistic regression, adjusted for multiple pregnancy and social risk. RESULTS: A total of 205 EP/ELBW and 201 controls were assessed at 2 years. Delay/concerns were more common in the EP/ELBW group compared with controls, for cognitive (OR 3.7 [95% confidence interval 2.3, 6.0]), language (5.3 [3.1, 9.0]) and motor (3.9 [2.3, 6.3]) development, and social-emotional competence (4.1 [1.6, 10.2]). CONCLUSION: Being born EP/ELBW has an adverse effect on cognitive, language and motor development, and social-emotional competence at 2 years' corrected age. Close developmental surveillance, including social-emotional development, is recommended.

Impact of the COVID-19 pandemic on access to healthcare, physical and mental health among patients with chronic kidney disease in Victoria, Australia.

PURPOSE: The COVID-19 pandemic has highlighted the difficulties healthcare systems face to care for patients with chronic diseases. In the state of Victoria, Australia, the government implemented a state-wide lockdown and restricted the delivery of healthcare to limit the spread of the virus. This study investigated the impact of the pandemic on healthcare access, mental and physical health for patients with chronic kidney disease (CKD). METHODS: Patients with stage 4 or 5 CKD were recruited from the nephrology unit of a metropolitan hospital in Victoria. Participants completed a quantitative and qualitative questionnaire that assessed the impact of the pandemic on their access to healthcare and mental and physical health. The quantitative data were analysed by a series of one-way between-groups analysis of variance (ANOVAs) comparing impact between different time periods since the beginning of the pandemic. RESULTS: Participants (n = 75) completed the questionnaire from 30 March 2020 to 29 September 2021. Participants reported significant disruptions to accessing healthcare in the initial 6 months of the pandemic. There were no significant differences in the quantitative assessments of physical and mental health of participants across the 18 months of this study. The participants' qualitative comments about disrupted normal activities, feeling vulnerable to COVID-19, transitioning to telehealth, feeling isolated and vaccination protection provided further insight into the cumulative negative mental health impact of the extended lockdown. CONCLUSION: Our findings highlight the importance of optimising telehealth to improve communication between CKD patients and their treating teams and continuing to monitor the impacts of pandemic restrictions on patients' mental and physical health.

A health impact assessment of gender inequities associated with psychological distress during COVID19 in Australia's most locked down state-Victoria.

BACKGROUND: Since March 2020, when the COVID19 pandemic hit Australia, Victoria has been in lockdown six times for 264 days, making it the world's longest cumulative locked-down city. This Health Impact Assessment evaluated gender disparities, especially women's mental health, represented by increased levels of psychological distress during the lockdowns. METHODS: A desk-based, retrospective Health Impact Assessment was undertaken to explore the health impacts of the lockdown public health directive with an equity focus, on the Victorian population, through reviewing available qualitative and quantitative published studies and grey literature. RESULTS: Findings from the assessment suggest the lockdown policies generated and perpetuated avoidable inequities harming mental health demonstrated through increased psychological distress, particularly for women, through psychosocial determinants. CONCLUSION: Ongoing research is needed to elucidate these inequities further. Governments implementing policies to suppress and mitigate COVID19 need to consider how to reduce harmful consequences of these strategies to avoid further generating inequities towards vulnerable groups within the population and increasing inequalities in the broader society.

Inclusion of Cultural and Linguistic Diversity in COVID-19 Public Health Research: Research Design Adaptations to Seek Different Perspectives in Victoria, Australia.

Participation of people from culturally and linguistically diverse (CALD) communities in public health research is often limited by challenges with recruitment, retention and second-language data collection. Consequently, people from CALD communities are at risk of their needs being marginalised in public health interventions. This paper presents intrinsic case analyses of two studies which were adapted to increase the cultural competence of research processes. Both cases were part of the Optimise study, a major mixed methods research study in Australia which provided evidence to inform the Victorian state government's decision-making about COVID-19 public health measures. Case study 1 involved the core Optimise longitudinal cohort study and Case study 2 was the CARE Victorian representative survey, an Optimise sub-study. Both case studies engaged cultural advisors and bilingual staff to adjust the survey measures and research processes to suit target CALD communities. Reflexive processes provided insights into the strengths and weaknesses of the inclusive strategies. Selected survey results are provided, demonstrating variation across CALD communities and in comparison to participants who reported speaking English at home. While in most cases a gradient of disadvantage was evident for CALD communities, some patterns were unexpected. The case studies demonstrate the challenge and value of investing in culturally competent research processes to ensure research guiding policy captures a spectrum of experiences and perspectives.

Guillain-Barré syndrome temporally associated with COVID-19 vaccines in Victoria, Australia.

Guillain-Barré syndrome (GBS) is an adverse event of special interest (AESI) for surveillance systems monitoring adverse events following immunisation (AEFI) with COVID-19 vaccines. Emerging data support a temporal association between GBS and adenovirus-vector COVID-19 vaccines. We present a case series of GBS reports submitted between February and November 2021 to our enhanced spontaneous surveillance system (SAEFVIC) in Victoria, Australia, following vaccination with either the adenovirus-vector vaccine Vaxzevria ChadOx1-S (AstraZeneca) or an mRNA vaccine (Comirnaty BNT162b2 [Pfizer-BioNTech] or Spikevax mRNA-1273 [Moderna]). For each report, Brighton Collaboration case definitions were used to describe diagnostic certainty. Severity was graded using the GBS Disability Score. The observed incidence of GBS following immunisation against COVID-19 was compared to expected background ICD10-AM G61.0 coded hospitalisations. There were 41 total cases of GBS reported to SAEFVIC following Vaxzevria (n = 38), Comirnaty (n = 3), or Spikevax (n = 0) vaccines. The observed GBS incidence rate exceeded the expected background rate for Vaxzevria only, with 1.85 reports per 100,000 doses following dose 1, higher than the expected rate of 0.39 hospital admissions per 100,000 adults within 42 days of vaccination. Of 38 GBS reports following Vaxzevria, the median age at vaccination was 66 years and median onset of symptoms was 14 days following immunisation. There was one death. Four cases initially categorised as GBS were later reclassified as acute-onset chronic inflammatory demyelinating polyneuropathy. Fatigue was the predominant persisting symptom reported at follow up. Additional global studies are required to characterise risk factors, clinical variability, and to provide precision and generalizability regarding AEFI risks such as GBS associated with different vaccine platforms, which will help inform communication of the potential benefits and risks of COVID19 vaccination.

Estimating the proportion of Victorians infected with COVID-19 during the Omicron BA.1 epidemic wave of January 2022 in Australia.

OBJECTIVE: To estimate the proportion of Victorians infected with COVID-19 in January 2022. METHODS: Between 11-19 February 2022 we conducted a nested cross-sectional survey on experiences of COVID-19 testing, symptoms, test outcome and barriers to testing during January 2022 in Victoria, Australia. Respondents were participants of the Optimise Study, a prospective cohort of adults considered at increased risk of COVID-19 or the unintended consequences of COVID-19-related interventions. RESULTS: Of the 577 participants, 78 (14%) reported testing positive to COVID-19, 240 (42%) did not test in January 2022 and 91 of those who did not test (38%) reported COVID-19-like symptoms. Using two different definitions of symptoms, we calculated symptomatic (27% and 39%) and asymptomatic (4% and 11%) test positivity. We extrapolated these positivity rates to participants who did not test and estimated 19-22% of respondents may have had COVID-19 infection in January 2022. CONCLUSION: The proportion of Victorians infected with COVID-19 in January 2022 was likely considerably higher than officially reported numbers. IMPLICATIONS FOR PUBLIC HEALTH: Our estimate is approximately double the COVID-19 case numbers obtained from official case reporting. This highlights a major limitation of diagnosis data that must be considered when preparing for future waves of infection.

Severity of COVID-19 among Residents in Aged Care Facilities in Victoria, Australia: A Retrospective Cohort Study Comparing the Delta and Omicron Epidemic Periods.

OBJECTIVES: During the COVID-19 pandemic, no country with widespread community transmission has avoided outbreaks or deaths in residential aged care facilities (RACFs). As RACF residents are at high risk of morbidity and mortality from COVID-19, understanding disease severity risk factors is imperative. DESIGN: This retrospective cohort study aimed to compare COVID-19 disease severity (hospitalization and deaths) and associated risk factors among RACF residents in Victoria, Australia, across Delta and Omicron epidemic periods. SETTINGS AND PARTICIPANTS: Resident case hospitalization risk (HR) and case fatality risk (CFR) were assessed using Victorian RACFs COVID-19 outbreaks data across 2 epidemic periods; Delta, 994 resident cases linked to 86 outbreaks; and Omicron, 1882 resident cases linked to 209 outbreaks. METHODS: Adjusting for outbreak-level clustering, age, sex, up-to-date vaccination status, and time since last vaccination, the odds of hospitalization and death were compared using mixed effects logistic regression. RESULTS: The HR and CFR was lower during the Omicron period compared with the Delta period [HR 8.2% vs 24.6%, odds ratio (OR) 0.17, 95% CI 0.11-0.26, and CFR: 11.4% vs 18.7%, OR 0.40, 95% CI 0.28-0.56]. During both periods, males had higher odds of hospitalization and odds of death; being up to date with vaccination reduced odds of hospitalization by 40% (excluding nonemergency patient transfers) and odds of death by 43%; and for each month since last vaccination, odds of hospitalization increased by 9% and odds of death by 16%. CONCLUSIONS AND IMPLICATIONS: This study provides empirical evidence of lower COVID-19 severity among RACF residents in the Omicron period and highlights the importance of up-to-date and timely vaccination to reduce disease severity in this cohort.