Longer-term outcome and safety data of repeated subcutaneous racemic ketamine for treatment-resistant depression (TRD) is lacking, as is knowledge of the impact of prior ketamine treatment on subsequent response.

To evaluate the effectiveness and safety of a 4-week course of subcutaneous racemic ketamine over 6 months and investigate whether prior ketamine treatment influences treatment response.

An open label extension (OLE) of a randomised controlled trial (RCT) was conducted at seven mood disorder centres in Australasia, enrolling consenting trial participants who had a Montgomery-Åsberg Depression Rating Scale (MADRS) score of ≥20 at post-trial assessment. Participants initially received twice-weekly 0.5 mg/kg subcutaneous racemic ketamine (fixed regimen) for 4 weeks. Dosing was revised after a Data Safety Monitoring Board recommendation, to a ‘flexible regimen’ (0.5–0.9 mg/kg with response-guided increments). Depression and safety outcomes were assessed throughout treatment, and 4 weeks and 6 months later.

130 RCT participants entered the OLE phase of whom 32 underwent the fixed OLE regimen and 98 the flexible regimen. At treatment end, 30% (36/116) had responded (MADRS reduction ≥50%), and 4 weeks later 17% (19/110) were ‘responders’. Over 50% experienced <25% MADRS reduction. There was no difference in depression response at any time point between regimens. Those treated with ketamine during the RCT showed a transient reduced response after first OLE treatment but at no other assessment point. There were no reports of suicide or suicidal behaviour requiring admission and only expected side-effects observed.

In a highly treatment-resistant sample, a 4-week course of subcutaneous racemic ketamine produced short-term clinical benefit in a minority of participants, with response rates declining substantially after treatment cessation, and no unexpected safety concerns. Exploratory subgroup analyses showed no association between prior RCT ketamine exposure and OLE outcomes.

ACTRN12616001096448 at www.anzctr.org.au.

This study examines gaps in mask-related behaviors, beliefs, and perceptions among healthcare personnel (HCP), investigates the influence of vaccination status on masking practices, and identifies opportunities to enhance adherence in clinical settings.

A survey was conducted among HCP providing direct patient care at State University of New York Upstate Medical University from November 2024 to January 2025.

A total of 655 HCP responded to the survey. Of these, 335 (51.1%) reported being up to date on coronavirus (COVID-19) vaccination, and 501 (76.5%) intended to receive the 2024 – 2025 influenza vaccine. Majority believed masking protects them (n = 381, 61%) and others (n = 400, 64.6%), perceived the workplace as carrying a high respiratory risk (n = 366, 58.6%), and believed patient masking offers protective benefits (n = 359, 57.4%). Self-reported masking rates were highest when participants were sick or symptomatic (n = 477, 72.8%) and lowest during respiratory specimen collection (n = 233, 35.6%). High adherence was observed when participants were symptomatic, among those who were up to date on their COVID-19 vaccination (n = 276, 82.4%) and who intended to receive the 2024 – 2025 influenza vaccine (n = 407, 81.2%).

These findings suggest self-reported masking adherence remains suboptimal, reflecting low perceived risk of COVID-19 infection in the postpandemic period. Targeted interventions highlighting masking as an important component of broader measures including vaccination, hand hygiene, and ventilation are needed to enhance hospital infection prevention and control.