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.

I know what you did last summer: a cross-sectional study of personal COVID-19 risk reduction strategies used by Victorian adults, December 2021-January 2022.

OBJECTIVE: We describe COVID-19 risk reduction strategies adopted by Victorian adults during December 2021-January 2022, a period of high COVID-19 infection and limited government mandated public health measures. METHODS: In February 2022, participants of a Victorian-based cohort study (Optimise) completed a cross-sectional survey on risk reduction behaviours during December 2021-January 2022. Regression modelling estimated the association between risk reduction and demographics. RESULTS: A total of 556 participants were included (median age 47 years; 75% women; 82% in metropolitan Melbourne). Two-thirds (61%) adopted at least one risk reduction behaviour, with uptake highest among younger participants (18-34 years; adjusted relative risk (aRR): 1.20, 95% confidence interval [CI]: 1.01, 1.41) and those with a chronic health condition (aRR: 1.17, 95% CI: 1.02, 1.35). CONCLUSIONS: Participants adopted their own COVID-19 risk reduction strategies in a setting of limited government restrictions, with young people more likely to adopt a risk reduction strategy that did not limit social mobility. IMPLICATION FOR PUBLIC HEALTH: A public health response to COVID-19 that focusses on promoting personal risk reduction behaviours, as opposed to mandated restrictions, could be enhanced by disseminating information on and increasing availability of effective risk reduction strategies tailored to segments of the population.

Engaging with communities to encourage adoption of a harm reduction approach to COVID-19.

Since the emergence of the Omicron variant in Australia in late 2021 there have been over 5.47 million cases and 4993 deaths, disproportionately impacting on people with social and structural disadvantage. However there has been increasing reluctance by governments to intervene to reduce the impact of COVID-19 transmission and its consequences. This commentary article provides a perspective on the support and guidance required to mitigate individuals and communities risk by using a harm reduction approach to highlight strategies that can reduce COVID-19 transmission and infection.

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.

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.

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.

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.

A multinational Delphi consensus to end the COVID-19 public health threat.

Despite notable scientific and medical advances, broader political, socioeconomic and behavioural factors continue to undercut the response to the COVID-19 pandemic^1,2. Here we convened, as part of this Delphi study, a diverse, multidisciplinary panel of 386 academic, health, non-governmental organization, government and other experts in COVID-19 response from 112 countries and territories to recommend specific actions to end this persistent global threat to public health. The panel developed a set of 41 consensus statements and 57 recommendations to governments, health systems, industry and other key stakeholders across six domains: communication; health systems; vaccination; prevention; treatment and care; and inequities. In the wake of nearly three years of fragmented global and national responses, it is instructive to note that three of the highest-ranked recommendations call for the adoption of whole-of-society and whole-of-government approaches¹, while maintaining proven prevention measures using a vaccines-plus approach² that employs a range of public health and financial support measures to complement vaccination. Other recommendations with at least 99% combined agreement advise governments and other stakeholders to improve communication, rebuild public trust and engage communities³ in the management of pandemic responses. The findings of the study, which have been further endorsed by 184 organizations globally, include points of unanimous agreement, as well as six recommendations with >5% disagreement, that provide health and social policy actions to address inadequacies in the pandemic response and help to bring this public health threat to an end.

A framework for considering the utility of models when facing tough decisions in public health: a guideline for policy-makers.

The COVID-19 pandemic has brought the combined disciplines of public health, infectious disease and policy modelling squarely into the spotlight. Never before have decisions regarding public health measures and their impacts been such a topic of international deliberation, from the level of individuals and communities through to global leaders. Nor have models-developed at rapid pace and often in the absence of complete information-ever been so central to the decision-making process. However, after nearly 3 years of experience with modelling, policy-makers need to be more confident about which models will be most helpful to support them when taking public health decisions, and modellers need to better understand the factors that will lead to successful model adoption and utilization. We present a three-stage framework for achieving these ends.

Quarantine preparedness – the missing factor in COVID-19 behaviour change? Qualitative insights from Australia

Background A key feature of the global public health response to contain and slow the spread of COVID-19 has been community-based quarantine and self-isolation. As part of The Optimise Study, this research sought to understand the factors that influence people’s ability to undertake home-based quarantine and isolation to contain the spread of COVID-19. Methods Semi-structured qualitative phone interviews (n = 25) were conducted by telephone with people who participated in community-based quarantine in Australia before 31 March 2020. The Capability Opportunity Motivation Behaviour model was used to conduct a thematic analysis. Results Participants required clear, accessible and trusted information to guide them in home-based quarantine and isolation. A sense of social responsibility and belief in the efficacy of the restrictions to reduce viral transmission aided their motivation. Access to essential needs, supportive living environments, and emotional support were required to adhere to restrictions, but few were prepared. Conclusions Findings demonstrate that in addition to having the capability and motivation to adhere to restrictions, it is vital that people are also encouraged to prepare for the challenge to ensure access to physical, social and emotional support. Findings also illustrate the importance of engaging communities in planning and preparedness for quarantine and self-isolation public health responses. Supplementary Information The online version contains supplementary material available at 10.1186/s12889-022-14185-7.

Quarantine preparedness - the missing factor in COVID-19 behaviour change? Qualitative insights from Australia.

BACKGROUND: A key feature of the global public health response to contain and slow the spread of COVID-19 has been community-based quarantine and self-isolation. As part of The Optimise Study, this research sought to understand the factors that influence people's ability to undertake home-based quarantine and isolation to contain the spread of COVID-19. METHODS: Semi-structured qualitative phone interviews (n = 25) were conducted by telephone with people who participated in community-based quarantine in Australia before 31 March 2020. The Capability Opportunity Motivation Behaviour model was used to conduct a thematic analysis. RESULTS: Participants required clear, accessible and trusted information to guide them in home-based quarantine and isolation. A sense of social responsibility and belief in the efficacy of the restrictions to reduce viral transmission aided their motivation. Access to essential needs, supportive living environments, and emotional support were required to adhere to restrictions, but few were prepared. CONCLUSIONS: Findings demonstrate that in addition to having the capability and motivation to adhere to restrictions, it is vital that people are also encouraged to prepare for the challenge to ensure access to physical, social and emotional support. Findings also illustrate the importance of engaging communities in planning and preparedness for quarantine and self-isolation public health responses.

Care Navigation Increases Initiation of Hepatitis C Treatment After Release From Prison in a Prospective Randomized Controlled Trial: The C-LINK Study.

Background: Prison-based hepatitis C treatment is safe and effective; however, many individuals are released untreated due to time or resource constraints. On community re-entry, individuals face a number of immediate competing priorities, and in this context, linkage to hepatitis C care is low. Interventions targeted at improving healthcare continuity after prison release have yielded positive outcomes for other health diagnoses; however, data regarding hepatitis C transitional care are limited. Methods: We conducted a prospective randomized controlled trial comparing a hepatitis C care navigator intervention with standard of care for individuals released from prison with untreated hepatitis C infection. The primary outcome was prescription of hepatitis C direct-acting antivirals (DAA) within 6 months of release. Results: Forty-six participants were randomized. The median age was 36 years and 59% were male. Ninety percent (n = 36 of 40) had injected drugs within 6 months before incarceration. Twenty-two were randomized to care navigation and 24 were randomized to standard of care. Individuals randomized to the intervention were more likely to commence hepatitis C DAAs within 6 months of release (73%, n = 16 of 22 vs 33% n = 8 of 24, P < .01), and the median time between re-entry and DAA prescription was significantly shorter (21 days [interquartile range {IQR}, 11-42] vs 82 days [IQR, 44-99], P = .049). Conclusions: Care navigation increased hepatitis C treatment uptake among untreated individuals released from prison. Public policy should support similar models of care to promote treatment in this high-risk population. Such an approach will help achieve hepatitis C elimination as a public health threat.

Real-world trends in incidence of bacterial sexually transmissible infections among gay and bisexual men using HIV pre-exposure prophylaxis (PrEP) in Australia following nationwide PrEP implementation: an analysis of sentinel surveillance data.

BACKGROUND: Although data from large implementation trials suggest that sexually transmissible infection (STI) risk increases among gay and bisexual men who initiate HIV pre-exposure prophylaxis (PrEP), there are few data on the trends in population-level STI incidence in the years following widespread PrEP implementation. We aimed to describe trends in bacterial STI incidence among gay and bisexual men using PrEP across Australia in the context of broad PrEP availability through Australia's subsidised medicines scheme. METHODS: We analysed linked clinical data from HIV-negative gay and bisexual men aged 16 years or older who had been prescribed PrEP across a sentinel surveillance clinical network, including 37 clinics in Australia, between Jan 1, 2016, and Dec 31, 2019. Patients were included if they had STI testing at least twice during the observation period. Repeat testing methods were used to calculate chlamydia, gonorrhoea, syphilis, and any STI incidence rates during individuals' periods of PrEP use. Incidence rate ratios (IRRs) for estimated change in incidence per half calendar year (6-month) period were calculated using negative binomial regression. Secondary analyses compared STI incidence rates across individuals initiating PrEP in each year from 2016 to 2019, as well as by length of time using PrEP (per each additional 6 months of PrEP use). FINDINGS: 22 730 men were included in the analyses. During the observation period, 11 351 chlamydia infections were diagnosed in 6630 (30·1%) of 22 034 men over 25 991·2 person-years of PrEP use (incidence rate 43·7 cases [95% CI 42·9-44·5] per 100 person-years). Chlamydia incidence decreased from 48·7 cases per 100 person-years in July-December, 2016, to 42·0 cases per 100 person-years in July-December, 2019 (IRR for estimated change per 6-month period 0·98 [95% CI 0·97-0·99]; p=0·0031). 9391 gonorrhoea infections were diagnosed in 5885 (26·9%) of 21 845 men over 24 858·7 person-years of PrEP use (incidence rate 37·8 cases [95% CI 37·0-38·5] per 100 person-years). Gonorrhoea incidence decreased from 45·5 cases per 100 person-years in July-December, 2016, to 37·2 cases per 100 person-years in July-December, 2019 (IRR 0·97 [95% CI 0·96-0·98]; p<0·0001). Declines in chlamydia and gonorrhoea incidence were most prominent in the first 18 months of observation and incidence was stable thereafter. 2062 syphilis infections were diagnosed in 1488 (7·7%) of 19 262 men over 21 978·9 person-years of PrEP use (incidence rate 9·4 cases [95% CI 9·0-9·8] per 100 person-years). Syphilis incidence increased from 6·2 cases per 100 person-years in July-December, 2016, to 9·8 cases per 100 person-years in July-December, 2019 (IRR 1·08 [95% CI 1·05-1·10]; p<0·0001). INTERPRETATION: Chlamydia and gonorrhoea incidence among gay and bisexual men using PrEP were highest in the early months of PrEP implementation in Australia and stabilised at slightly lower rates thereafter following wider PrEP uptake. Lower prospective STI risk among people initiating PrEP in later years contributed to the observed trends in STI incidence. Widespread PrEP implementation can contribute to increased STI screening and detection. FUNDING: Australian Department of Health, National Health and Medical Research Council.

The impact of COVID-19 on public health systems in the Pacific Island Countries and Territories.

The Pacific Island Countries and Territories (PICTs) have experienced the coronavirus disease (COVID-19) pandemic in different ways and with different timelines, with some experiencing large outbreaks leading to high levels of morbidity and mortality with significant strain on health systems, while others have had no local transmission or delayed transmission until after vaccine rollouts started. Regardless of COVID-19 trends, the pandemic has had a large impact on the social, political, and economic landscape in the Pacific, the effects of which are still being understood. However, the pandemic has also put renewed focus and investment into public health systems and provided an opportunity for the PICTs to build on existing systems and recent capacity strengthening to improve public health in the Region. Funding: Leila Bell was supported by an Australian Government Research Training Program (RTP) Scholarship. Other funding sources had no role in paper design, data collection, data analysis, interpretation, or writing of the paper.

Impact of COVID-19 lockdown restrictions on hepatitis C testing in Australian primary care services providing care for people who inject drugs.

In 2020, the Australian state of Victoria experienced the longest COVID-19 lockdowns of any jurisdiction, with two lockdowns starting in March and July, respectively. Lockdowns may impact progress towards eliminating hepatitis C through reductions in hepatitis C testing. To examine the impact of lockdowns on hepatitis C testing in Victoria, de-identified data were extracted from a network of 11 services that specialize in the care of people who inject drugs (PWID). Interrupted time-series analyses estimated weekly changes in hepatitis C antibody and RNA testing from 1 January 2019 to 14 May 2021 and described temporal changes in testing associated with lockdowns. Interruptions were defined at the weeks corresponding to the start of the first lockdown (week 14) and the start (week 80) and end (week 95) of the second lockdown. Pre-COVID, an average of 80.6 antibody and 25.7 RNA tests were performed each week. Following the first lockdown in Victoria, there was an immediate drop of 23.2 antibody tests and 8.6 RNA tests per week (equivalent to a 31% and 46% drop, respectively). Following the second lockdown, there was an immediate drop of 17.2 antibody tests and 4.6 RNA tests per week (equivalent to a 26% and 33% drop, respectively). With testing and case finding identified as a key challenge to Australia achieving hepatitis C elimination targets, the cumulative number of testing opportunities missed during lockdowns may prolong efforts to find, diagnose and engage or reengage in care of the remaining population of PWID living with hepatitis C.

The impact of three progressively introduced interventions on second wave daily COVID-19 case numbers in Melbourne, Australia.

BACKGROUND: The city of Melbourne, Australia experienced two waves of the COVID-19 epidemic peaking, the first in March and a more substantial wave in July 2020. During the second wave, a series of control measure were progressively introduced that initially slowed the growth of the epidemic then resulted in decreasing cases until there was no detectable local transmission. METHODS: To determine the relative efficacy of the progressively introduced intervention measures, we modelled the second wave as a series of exponential growth and decay curves. We used a linear regression of the log of daily cases vs time, using a four-segment linear spline model corresponding to implementation of the three successive major public health measures. The primary model used all reported cases between 14 June and 15 September 2020 then compared the projection of the model with observed cases predicting future case trajectory up until the 31 October 2020 to assess the use of exponential models in projecting the future course and planning future interventions. The main outcome measures were the exponential daily growth constants, analysis of residuals and estimates of the 95% confidence intervals for the expected case distributions, comparison of predicted daily cases. RESULTS: The exponential growth/decay constants in the primary analysis were: 0.122 (s.e. 0.004), 0.035 (s.e. 0.005), - 0.037 (s.e. 0.011), and - 0.069 (s.e. 0.003) for the initial growth rate, Stage 3, Stage 3 + compulsory masks and Stage 4, respectively. Extrapolation of the regression model from the 14 September to the 31 October matched the decline in observed cases over this period. CONCLUSIONS: The four-segment exponential model provided an excellent fit of the observed reported case data and predicted the day-to-day range of expected cases. The extrapolated regression accurately predicted the decline leading to epidemic control in Melbourne.

Hepatitis B and pregnancy: understanding the experiences of care among pregnant women and recent mothers in metropolitan Melbourne

Background Pregnant women are a priority group for hepatitis B testing. Guideline-based care during antenatal and post-partum periods aims to prevent mother-to-child transmission of hepatitis B virus and lower the risk of liver complications in mothers. This qualitative study explored knowledge of hepatitis B and experiences of hepatitis B related care among pregnant women and mothers. Methods Semi-structured interviews were conducted with thirteen women with hepatitis B who were attending antenatal or post-partum hepatitis B care. The interviews were thematically analysed to assess knowledge and understanding of hepatitis B. Participants were recruited from specialist clinics in metropolitan Melbourne between August 2019 and May 2020. Results Four major themes were identified from interviews: (1) knowledge and understanding of hepatitis B, (2) treatment pathways, (3) accessing hepatitis B related care, and (4) disclosing status to friends. Most participants displayed an understanding of hepatitis B transmission, including mother to child transmission. The main motivator of post-partum attendance was reassurance gained concerning their child’s health. Sources of hepatitis B information included doctors, online information and family. Participants identified parents and siblings as sources of support and reported an unwillingness to disclose hepatitis B status to friends. Conclusions Women attending antenatal or post-partum care reported having overall positive experiences, particularly regarding reassurance of their child’s health, but displayed misconceptions around horizontal transmission. Knowledge gained from these results can contribute to the development of targeted models of care for pregnant women and mothers with young children to ensure their successful linkage to care.