Royal Darwin Hospital

Background: Otoacariasis, the infestation of the external auditory canal (EAC) by ticks, is a common presentation in endemic regions and an emerging clinical consideration in Australia. Conventional agents, including local anaesthetics and oils, often fail to rapidly inactivate hard ticks, potentially prolonging patient discomfort and increasing the risk of infectious complications. Dimethicone, a low-toxicity, low-viscosity organosilicon compound, has demonstrated efficacy against arthropods but has not been formally evaluated for hard tick otoacariasis. This study aims to investigate whether dimethicone outperforms conventional agents in inactivating hard ticks. Methods: In a laboratory-based experiment, 48 Rhipicephalus haemaphysaloides ticks were randomly allocated into four treatment groups (n=12 per group): dimethicone, olive oil, coconut oil, and 2% xylocaine. Ticks were submerged in the test agent and observed under magnification, with time to complete inactivity recorded. Inactivity was defined as cessation of all leg movement despite stimulation. Data were analysed using Statistical Package for Social Sciences (SPSS), with between-group comparisons performed to assess differences in time to inactivity. Results: Time to inactivity was significantly shorter in the dimethicone group (75.0 +/- 10.4 s) compared with olive oil (753.3 +/- 78.3 s), coconut oil (1,056.6 +/- 122.8 s), and 2% xylocaine, in which no inactivity was observed within the 1,800-second observation period (all comparisons P<0.001). Conclusions: Dimethicone rapidly and reliably inactivated hard ticks in vitro, outperforming commonly used agents. This effect is likely mediated by its ability to penetrate the tick spiracular system and impair respiration. Given its favourable safety profile and rapid action, dimethicone may represent a practical option for managing otoacariasis in outpatient and emergency settings. Further in vivo studies are warranted to confirm clinical applicability in the Australian context.

Household overcrowding is a major driver of acute rheumatic fever and rheumatic heart disease, along with other adverse social, cultural and health outcomes in remote Aboriginal communities. Overcrowding is compounded by poor thermal performance of current housing, energy insecurity and climate change. Despite strong evidence of the causes of rheumatic heart disease, upstream prevention through housing design remains underexplored. Wilya Janta, an Aboriginal-led organisation in Tennant Creek, has developed the Explain Home design: a culturally responsive, climate-adapted prototype designed to reduce overcrowding-related harms. With an unprecedented $4 billion investment in remote housing, health professionals have a critical role in advocating for evidence-informed, culturally safe housing as a form of preventive health intervention to improve equity and outcomes.

BACKGROUND:MRI is recommended for men with clinical suspicion of significant prostate cancer. Those with high clinical risk but non-suspicious or equivocal MRI often undergo prostate biopsy, but have a low likelihood of clinically significant prostate cancer, and a high incidence of clinically insignificant prostate cancer. We aimed to investigate whether gallium-68 ([68Ga]Ga)-prostate-specific membrane antigen (PSMA)-11 PET-CT could reduce the number of people requiring prostate biopsy and limit biopsy to targeted cores, without compromising clinically significant prostate cancer diagnosis. METHODS:In this multicentre, non-inferiority, phase 3, randomised controlled trial, done at at seven Australian hospitals, we recruited biopsy-naive participants with clinical suspicion of significant prostate cancer, equivocal (Prostate Imaging-Reporting and Data System [PI-RADS] 3) or non-suspicious (PI-RADS 2) MRI but high clinical risk (eg, prostate-specific antigen [PSA] density of >0·1 ng/mL/mL, strong family history of prostate cancer, abnormal digital rectal examination, BRCA mutation, PSA >10 ng/mL, PSA doubling time <36 months, or PSA velocity >0·75 ng/mL per year), PSA of 20 ng/mL or less, and clinical T2 disease or less. Participants were randomly assigned (1:1) using a centralised web-based system to undergo [68Ga]Ga-PSMA-11 PET-CT (experimental group) or systematic transperineal prostate biopsy (control group), using block sizes of two or four and stratification by study site. There was no masking for participants or investigators. Participants with positive [68Ga]Ga-PSMA-11 PET-CT (PRIMARY score 3-5) underwent PSMA-PET-targeted transperineal prostate biopsies, whereas those with a negative result (PRIMARY score 1-2) avoided biopsy. The co-primary outcomes were the proportion of participants with clinically significant prostate cancer, defined as a Gleason score of 3 + 4 (≥10% pattern 4) or higher, and the proportion of participants in the [68Ga]Ga-PSMA-11 PET-CT group who avoided biopsy within 6 months of random assignment. A two-sided 95% Wald CI based on a binomial model was used to estimate the risk difference in the proportion of participants with clinically significant prostate cancer (non-inferiority margin 10%) and to estimate the proportion of participants in the experimental group who had avoided biopsy 6 months after random assignment (20% threshold), analysed based on intention to treat. This trial is registered with ClinicalTrials.gov, NCT05154162, and participant follow-up is ongoing. FINDINGS:Between March 2, 2022, and Aug 24, 2025, 660 eligible male participants were enrolled and had a median age of 61 years (IQR 56-66), a median PSA of 5·2 ng/mL (4·0-7·0), and a median PSA density of 0·13 ng/mL/mL (0·09-0·17). There were PI-RADS 2 in 335 (51%) participants and PI-RADS 3 in 325 (49%) participants. Ethnicity data were not collected. 329 (50%) were assigned to the control group with systematic transperineal prostate biopsy, and 331 (50%) were assigned to the experimental group with [68Ga]Ga-PSMA-11 PET-CT. The proportion of participants with clinically significant prostate cancer in the experimental group (39 [12%] of 331) was non-inferior to the control (51 [16%] of 329; difference -3·7% [95% CI -8·9 to 1·5%]; p=0·0093). Use of [68Ga]Ga-PSMA-11 PET-CT avoided biopsy in 163 (49%) of 331 participants (95% CI 44 to 55%; p <0·0001). After prostate biopsy, participants reported similar proportions of pain (33 [21%] in the experimental group vs 62 [21%] in the control group), haematuria (60 [38%] vs 126 [43%]), and haematospermia (77 [48%] vs 133 [45%]). INTERPRETATION:[68Ga]Ga-PSMA-11 PET-CT could have the potential to improve the diagnostic pathway of patients with a high clinical risk but non-suspicious or equivocal prostate MRI. Further research, including health-economic analyses and validation with other PSMA radiopharmaceuticals, are needed to confirm the clinical implementation and generalisability of this approach. FUNDING:Prostate Cancer Foundation, National Health and Medical Research Council, St Vincent's Curran Foundation, and Peter MacCallum Cancer Foundation.

BACKGROUND:Whether treatment with balanced crystalloid fluid leads to better outcomes than 0.9% saline in children treated for septic shock is debated. METHODS:In this pragmatic clinical trial conducted at 47 emergency departments in five countries, patients (2 months to <18 years of age) with suspected septic shock and abnormal perfusion were randomly assigned to receive fluid resuscitation with either balanced fluid or 0.9% saline for up to 48 hours. The primary outcome was a major adverse kidney event (a composite of death, new renal-replacement therapy, or persistent kidney dysfunction) at 30 days after enrollment or hospital discharge, whichever occurred first. RESULTS:Of 9041 enrolled patients, 277 (6.1%) in the balanced-fluid group and 282 (6.2%) in the 0.9%-saline group withdrew from the trial, leaving 4235 and 4247 patients, respectively, for analysis. A primary-outcome event occurred in 137 patients (3.4%) in the balanced-fluid group and in 124 (3.0%) in the 0.9%-saline group (difference, 0.4 percentage points; 95% confidence interval [CI], -0.5 to 1.3; risk ratio, 1.10; 95% CI, 0.88 to 1.40; P = 0.85). The median number of hospital-free days during 28 days after enrollment was 23 (interquartile range, 19 to 25) in both groups. Hyperchloremia occurred in 868 patients (31.4%) in the balanced-fluid group and in 1383 (49.0%) in the 0.9%-saline group; hypernatremia in 52 (1.8%) and 89 (3.1%), respectively; and hyperlactatemia in 260 (19.8%) and 228 (16.7%). No differences in other safety outcomes or adverse events were seen. CONCLUSIONS:Among children treated for septic shock, no significant difference was seen in the incidence of death, new renal-replacement therapy, or persistent kidney dysfunction when fluid resuscitation was administered with balanced fluid as compared with 0.9% saline. (Funded by Eunice Kennedy Shriver National Institute of Child Health and Human Development and others; PRoMPT BOLUS ClinicalTrials.gov number, NCT04102371.).

Importance:In February 2025, Australia introduced maternal vaccination with bivalent respiratory syncytial virus prefusion F protein-based vaccine (RSVpreF) in the National Immunization Program for pregnant individuals from 28 weeks' gestation as the primary, year-round strategy to prevent RSV disease in infants 6 months of age or younger. Objective:To estimate effectiveness of RSVpreF vaccination during pregnancy against infant RSV hospitalization in Australia. Design, Setting, and Participants:This retrospective case-control study with a test-negative design was conducted in 9 hospitals across Australia with year-round respiratory testing for acute respiratory illness (ARI) among infants born from 28 weeks' gestation and hospitalized with ARI at 6 months of age or younger, March 1, 2025, through February 28, 2026. Data were analyzed March 2026 through May 2026. Exposure:Maternal RSVpreF vaccination administered from 28 weeks' gestation and 14 days or more before delivery. Main Outcomes and Measures:Maternal RSVpreF effectiveness was evaluated against hospitalization for RSV lower respiratory tract disease (RSV-LRTD, primary objective), severe RSV-LRTD, and RSV-ARI. Logistic regression with confounder adjustment was used to calculate vaccine effectiveness (VE) as (1 - adjusted odds ratio) × 100%. Results:Of 1012 infants hospitalized with ARI, 655 had LRTD, with 114 of 386 case infants (30%) and 171 of 269 control infants (64%) born to RSVpreF-vaccinated mothers (median [IQR] gestational age at vaccination, 31 weeks [29-33]). Median (IQR) maternal age at delivery was 32 years (29-35). Median (IQR) age of infants hospitalized for LRTD was 52 days (30-89); 495 of 655 (76%) were aged 3 months or younger. VE against RSV-LRTD hospitalization was 77.8% (95% CI, 66.4%-85.3%) among infants from birth through 6 months of age, 80.2% (95% CI, 71.1%-86.5%) among infants from birth through 3 months of age, 86.3% (95% CI, 79.0%-91.1%) among infants from birth through 2 months of age, and 68.2% (95% CI, 42.2%-82.5%) among infants older than 2 months through 4 months of age. Comparable VE among infants aged 6 months or younger was observed for severe RSV-LRTD (80.4%; 95% CI, 54.4%-91.6%) and RSV-ARI (80.8%; 95% CI, 70.4%-87.6%) hospitalization, with similar age-specific trends. VE was consistent across stratifications by gestational age at vaccination, vaccination to delivery time interval, and proximal administration with other vaccines during pregnancy. Descriptively, among all infants hospitalized with ARI, 161 of 499 (32%) born to RSVpreF-unvaccinated mothers had severe LRTD, while 87 of 513 (17%) born to RSVpreF-vaccinated mothers had severe LRTD. Conclusions and Relevance:Findings in this case-control study demonstrate high year-round effectiveness of RSVpreF vaccination against RSV-associated hospitalization in infants 6 months of age or younger in the first year following introduction in Australia, with the highest VE observed in the earliest age intervals. Future analyses with larger sample sizes will evaluate VE among additional subgroups.