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 15–29 years 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.

The severity of wildfires increases globally, and return intervals decrease. Fires can benefit biodiversity, as post-burn early successional stages provide diverse habitats and niches for many species. How fire disturbance affects niche use and niche overlap of species is poorly understood so far. We studied the effect of anthropogenic fire on breeding habitat use, niche breadth and niche overlap of five sympatric bunting species breeding in wetlands of the Amur River floodplain (Russian Far East). Fire frequency, measured as the time an area burnt in the period 2000 to 2017, was mapped from Landsat imagery and related to the presence or absence of the species. Niche breadth and niche overlap were calculated separately for occurrences in burned (within the study year) and unburned patches. Fire frequency characterized differences in niche use among the species, but the probability of presence was not affected by recent fire in four of five species. Niche breadth was significantly lower in recently burned patches, but we found no increase in niche overlap between species after fire. Instead, the studied species seemed to occupy similar patches before and after fire, possibly because of a high site fidelity. Our results clearly show that fire frequency is a major determinant for the niche separation in the five studied species, while recent fire does not affect niche overlap.

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.

Objective: The prevalence of common mental disorders (CMDs, depression/anxiety) among Australian adolescents is increasing. Evidence is needed to inform how prevention efforts can be focused for greatest impact. This study used a compartmental model to estimate how investments could be optimally allocated across interventions to prevent CMDs in adolescents, and the corresponding health and economic benefits. Methods: The Australian 0- to 19-year-old population was disaggregated by age (0–9, 10–14, 15–19), sex (male, female) and CMD experience (never, currently, previously). Twelve prevention interventions were included following targeted reviews. The model was calibrated to Australian population survey data and included sociodemographic risk factors from the literature that were relevant for included interventions (bullying, financial stress, poor school connectedness, racial discrimination, child maltreatment). An optimisation estimated how an additional AUD$50 million–AUD$1 billion per annum over 2024–2050 could be allocated across interventions to maximise the number of adolescents turning 20 without a lifetime experience of CMD. Results: The benefit–cost ratios of interventions varied widely depending on whether they impacted CMDs directly or indirectly by reducing a risk factor, and also whether CMD was their primary purpose or not (e.g. poverty interventions). Optimally investing AUD$50 million–AUD$1 billion p.a. over 2024–2050 could lead to 144,577–791,277 fewer adolescents experiencing a CMD by age 20 (AUD$5064–AUD$18,507/lifetime CMD experience averted), with lower bound benefit–cost ratios ranging from 5.0 to 19.2. Optimally, budget allocations should include combinations of interventions targeting different age groups, sub-populations and risk factors. Conclusions: Investing in evidence-based prevention interventions for adolescent mental health is likely to have a favourable return-on-investment.