A Framework for Assessing the Impact of Outbreak Response Immunization Programs.

The impact of outbreak response immunization (ORI) can be estimated by comparing observed outcomes to modelled counterfactual scenarios without ORI, but the most appropriate metrics depend on stakeholder needs and data availability. This study developed a framework for using mathematical models to assess the impact of ORI for vaccine-preventable diseases. Framework development involved (1) the assessment of impact metrics based on stakeholder interviews and literature reviews determining data availability and capacity to capture as model outcomes; (2) mapping investment in ORI elements to model parameters to define scenarios; (3) developing a system for engaging stakeholders and formulating model questions, performing analyses, and interpreting results; and (4) example applications for different settings and pathogens. The metrics identified as most useful were health impacts, economic impacts, and the risk of severe outbreaks. Scenario categories included investment in the response scale, response speed, and vaccine targeting. The framework defines four phases: (1) problem framing and data sourcing (identification of stakeholder needs, metrics, and scenarios); (2) model choice; (3) model implementation; and (4) interpretation and communication. The use of the framework is demonstrated by application to two outbreaks, measles in Papua New Guinea and Ebola in the Democratic Republic of the Congo. The framework is a systematic way to engage with stakeholders and ensure that an analysis is fit for purpose, makes the best use of available data, and uses suitable modelling methodology.

Impact of COVID-19 on routine childhood immunisations in low- and middle-income countries: A scoping review.

Routine vaccines are critical to child health. The COVID-19 pandemic significantly impacted essential health services, particularly in low-and middle-income countries (LMICs). We reviewed literature to determine the impact of COVID-19 on service delivery and uptake of routine childhood immunisation in LMICs. We reviewed papers published between March 2020 and June 2022 using a scoping review framework, and assessed each paper across the World Health Organisation health system strengthening framework. Our search identified 3,471 publications; 58 studies were included. One-quarter of studies showed routine childhood immunisation coverage declined (10% to 38%) between 2019 to 2021. Declines in the number of vaccine doses administered (25% to 51%), timeliness (6.2% to 34%), and the availability of fixed and outreach services were also reported. Strategies proposed to improve coverage included catch-up activities, strengthening supply chain and outreach services. Re-focusing efforts on increasing coverage is critical to improve child health and reduce the likelihood of disease outbreaks.

Attitudes Towards Treatment as Prevention Among PrEP-Experienced Gay and Bisexual Men in Australia.

The introduction of HIV pre-exposure prophylaxis (PrEP) has the potential to impact the attitudes gay and bisexual men (GBM) who consequently choose to take PrEP have towards treatment as prevention (TasP), and the extent to which they are willing to have condomless anal intercourse (CLAI) with an HIV-positive sexual partner who has an undetectable viral load (UVL). Using a cross-sectional sample from an observational cohort study conducted from August 2018 to March 2020, we examined the extent to which PrEP-experienced GBM are willing to have CLAI with a partner who has a UVL. Simple and multiple logistic regression models were used to identify associated variables. Of the 1386 participants included in the analyses, 79.0% believed in the effectiveness of TasP, and 55.3% were willing to have CLAI with a partner who has a UVL. Wiling participants were less worried about getting HIV when taking PrEP and more likely to believe in TasP. Further research is needed to better understand the gap between belief in TasP and willingness to have CLAI with a partner who has a UVL among PrEP-experienced GBM.

Factors Associated With Willingness to Use Daily Antibiotics as Sexually Transmitted Infection Prophylaxis Among HIV Preexposure Prophylaxis-Experienced Gay and Bisexual Men in Australia.

BACKGROUND: Gay and bisexual men (GBM) who use HIV preexposure prophylaxis (HIV-PrEP) have high rates of bacterial sexually transmitted infections (STIs). The use of daily antibiotics as STI preexposure prophylaxis (STI-PrEP) may be appealing to GBM who are using or have previously used HIV-PrEP (HIV-PrEP-experienced) for the prevention of bacterial STIs. METHODS: We examined willingness to use daily STI-PrEP among a cross-sectional sample of HIV-PrEP-experienced GBM in Australia who participated in an observational online cohort study from August 2018 to March 2020. Factors associated with willingness to use daily STI-PrEP were determined using bivariate and multivariate logistic regression. RESULTS: Of the 1347 participants, half (54.3%) were willing to use daily STI-PrEP. Factors independently associated with greater willingness to use daily STI-PrEP included having >10 sexual partners in the last 6 months, using methamphetamine in the last 6 months, being more conscious about avoiding STIs, having a greater number of STIs since commencing HIV-PrEP, being willing to take HIV-PrEP for as long as they were at risk of acquiring HIV, and only using condoms when a sexual partner requested them. Conversely, factors associated with less willingness to use daily STI-PrEP included being university educated, using nondaily dosing regimens of HIV-PrEP, preferring event-driven HIV-PrEP, and being concerned about long-term HIV-PrEP adverse effects. CONCLUSIONS: Sexually transmitted infection PrEP is likely to be appealing to many HIV-PrEP-experienced GBM, especially those who engage in activities associated with a higher risk of STI transmission. However, they are less likely to be willing to use STI-PrEP unless it aligns with their HIV-PrEP dosing regimen, suggesting that research into the safety and efficacy of alternative STI prophylaxis dosing options should be prioritized.

Characteristics of Human Immunodeficiency Virus (HIV) Seroconversions in a Large Prospective Implementation Cohort Study of Oral HIV Preexposure Prophylaxis in Men Who Have Sex with Men (EPIC-NSW).

BACKGROUND: Most human immunodeficiency virus (HIV) seroconversions in people who have initiated preexposure prophylaxis (PrEP) occur in the context of insufficient adherence. We describe participants who seroconverted after being dispensed PrEP in a large PrEP implementation study in Australia. METHODS: Expanded PrEP Implementation in Communities in New South Wales was an implementation study of daily oral PrEP in individuals aged ≥18 years at high risk for acquiring HIV. HIV seroconversions were defined as a positive HIV test by either antigen, antibody, or detectable HIV viral load after enrollment. Insufficient adherence, measured by dispensing logs or participant self-report, was defined as <4 PrEP doses per week. RESULTS: A total of 9596 participants were enrolled and dispensed PrEP between 1 March 2016 and 30 April 2018; 30 were diagnosed with HIV by 31 March 2019. The median (interquartile range [IQR]) age was 31 (25-38) years, all identified as male, 29 (97%) identified as gay or homosexual, and 20 (69%) lived in a postcode with a low concentration of gay male residents. The median (IQR) days from first PrEP dispensing to diagnosis was 409 (347-656). There was no evidence that participants who seroconverted had been sufficiently adherent to PrEP. Nineteen (63%) participants who seroconverted were diagnosed with chlamydia, gonorrhoea, syphilis, or new hepatitis C infection. One participant had resistance to emtricitabine (M184V mutation) at diagnosis. CONCLUSIONS: Participants who seroconverted were insufficiently adherent to PrEP despite being at high risk for acquiring HIV. Understanding the reasons for poor PrEP adherence in individuals who subsequently acquire HIV is critical to improving PrEP effectiveness.

Genomic characterisation reveals a dominant lineage of SARS-CoV-2 in Papua New Guinea.

The coronavirus disease pandemic has highlighted the utility of pathogen genomics as a key part of comprehensive public health response to emerging infectious diseases threats, however, the ability to generate, analyse, and respond to pathogen genomic data varies around the world. Papua New Guinea (PNG), which has limited in-country capacity for genomics, has experienced significant outbreaks of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with initial genomics data indicating a large proportion of cases were from lineages that are not well defined within the current nomenclature. Through a partnership between in-country public health agencies and academic organisations, industry, and a public health genomics reference laboratory in Australia a system for routine SARS-CoV-2 genomics from PNG was established. Here we aim to characterise and describe the genomics of PNG's second wave and examine the sudden expansion of a lineage that is not well defined but very prevalent in the Western Pacific region. We generated 1797 sequences from cases in PNG and performed phylogenetic and phylodynamic analyses to examine the outbreak and characterise the circulating lineages and clusters present. Our results reveal the rapid expansion of the B.1.466.2 and related lineages within PNG, from multiple introductions into the country. We also highlight the difficulties that unstable lineage assignment causes when using genomics to assist with rapid cluster definitions.

Low Prior Exposure and Incidence of Hepatitis C in Human Immunodeficiency Virus-Negative Gay and Bisexual Men Taking Preexposure Prophylaxis (PrEP): Findings From the Expanded PrEP Implementation in Communities-New South Wales Prospective Implementation Study.

BACKGROUND: The use of preexposure prophylaxis (PrEP) for the prevention of human immunodeficiency virus (HIV) has raised concerns of increased sexual risk behaviors. These behaviors may be associated with increased incidence of sexually acquired hepatitis C virus (HCV) among gay and bisexual men. METHODS: The Expanded PrEP Implementation in Communities-New South Wales (EPIC-NSW) study was a cohort study of daily coformulated tenofovir disoproxil fumarate and emtricitabine for HIV prevention. We recruited 9596 people at high risk of HIV acquisition from 31 clinics across New South Wales and the Australia Capital Territory in Australia. We report prior exposure to HCV and incidence in this cohort between 2016 and 2019. RESULTS: At least 1 HCV test result was available for 8658 (90.2%) participants. These individuals had a median age of 34 years (interquartile range, 28-43), most of whom were male (8530, 98.5%), identified as gay (7944, 91.8%), and were born in Australia (51.8%). Prior exposure to HCV was detected among 81 participants at baseline (0.9%; 95% confidence interval [CI]: .71.2). Twenty of 8577 participants were diagnosed with incident infection (rate 0.2/100 person-years [95% CI: .1-.3/100 person-years]). They were significantly older (median age 41 years vs 34 years, P = .044), and more likely to report methamphetamine use at baseline (incidence rate ratio, 2.7 [95% CI: 1.00-7.2]) than those without incident infection. CONCLUSIONS: In this population of PrEP users, HCV prior exposure and incidence were low. With high levels of HCV and HIV testing and treatment, the dual goals of HIV and HCV elimination could be achieved in this population. Clinical Trials Registration: number NCT02870790.

Incorrect Knowledge of Event-Driven PrEP "2-1-1" Dosing Regimen Among PrEP-Experienced Gay and Bisexual Men in Australia.

BACKGROUND: Event-driven pre-exposure prophylaxis (ED-PrEP), when taken according to the "2-1-1" dosing method, is highly effective at preventing HIV acquisition for gay, bisexual, and other men who have sex with men (GBM). Any missed doses when using ED-PrEP drastically reduce its effectiveness, so it is vital that people using this method know how to take it correctly. This study investigated Australian GBM's awareness of ED-PrEP and their knowledge of how to take it correctly. METHOD: We conducted a survey of 1471 PrEP-experienced GBM in Australia, between October 2019 and March 2020. The survey assessed awareness and knowledge of the 3 components of the "2-1-1" ED-PrEP dosing regimen (number of pills for loading dose, timing of loading dose, and number of days after sex to take PrEP pills) among GBM. Characteristics associated with ED-PrEP awareness and correct knowledge of how to take ED-PrEP were assessed with multivariate logistic regression. RESULTS: Two-thirds (n = 1004, 68.4%) had heard of ED-PrEP, of whom only one-eighth (n = 125, 12.5%) knew the correct details of the "2-1-1" ED-PrEP method; one-third (n = 339, 33.8%) did not know any of the 3 key components. Awareness of ED-PrEP and correct knowledge was associated with greater belief in PrEP efficacy, university education, and intention to take a nondaily PrEP regimen in the next 6 months. CONCLUSIONS: Although ED-PrEP awareness was considerable, most participants did not know how to use ED-PrEP correctly. Further work is needed to increase awareness and knowledge of ED-PrEP among GBM.

Preferences for Current and Future PrEP Modalities Among PrEP-Experienced Gay and Bisexual Men in Australia.

Alternatives to daily dosing of HIV pre-exposure prophylaxis (PrEP) are continuing to emerge. From October 2019 to March 2020, we conducted an online survey of PrEP-experienced gay and bisexual men in Australia about interest in and preference for four different PrEP modalities: daily dosing, event-driven dosing, long-acting injectable (LAI)-PrEP and subdermal PrEP implants. Using data from 1477 participants, we measured interest and preference of different modalities using multivariate logistic regression. High proportions of participants were interested in LAI-PrEP (59.7%), daily PrEP (52.0%), PrEP implants (45.3%) and event-driven PrEP (42.8%). LAI-PrEP was the most frequently selected preference (30.5%), followed by PrEP implants (26.3%), daily PrEP (21.4%) and event-driven PrEP (21.2%). Higher interest and preference for non-daily PrEP modalities were associated with being concerned about side effects and perceived difficulties with daily adherence. As novel modalities emerge, attitudes to them should be considered in public health messaging to facilitate informed decision-making.

Overcoming barriers to HIV pre-exposure prophylaxis (PrEP) coverage in Australia among Medicare-ineligible people at risk of HIV: results from the MI-EPIC clinical trial.

Background Overseas-born people who are ineligible for government-subsidised health care experience barriers to accessing HIV pre-exposure prophylaxis (PrEP) in Australia. This study aimed to assess a program providing free PrEP to overseas-born adults at risk of acquiring HIV. Methods Medicare-Ineligible Expanded Implementation in Communities (MI-EPIC) was a single-arm, open-label trial of daily tenofovir disoproxil fumarate/emtricitabine as PrEP. Six clinics recruited Medicare-ineligible adults who met HIV risk criteria in New South Wales, Australia. We recorded data on HIV and sexually transmitted infection (STI) diagnoses, and PrEP dispensing from July 2019 to June 2020. PrEP adherence as a medication possession ratio (MPR) was calculated as pills dispensed divided by days. We administered an optional survey on behaviours and attitudes to PrEP and sexual health. Results The 221 participants (206 men; 93.2%) had a median age of 29years (IQR 26-34). Participants were mostly born in Asia (53.4%), Latin America or the Caribbean (25.3%), or Europe (10.9%). Adherence was high; 190 participants (86.0%) had an MPR of >60%. Of 121 survey participants, 42 (34.7%) completed the survey in a language other than English. Of participants who had not used PrEP in the 6months before enrolment (n=45, 37.2%), the most common reasons were cost (n=22, 48.9%), and lack of knowledge about accessing PrEP (n=20, 44.4%). Conclusions Medicare-ineligible people at risk of HIV demonstrate high adherence when given access to free PrEP and translated information. Increasing PrEP awareness and reducing barriers to accessing PrEP in this high-risk population should be priorities in HIV prevention.

Long-term protection from HIV infection with oral HIV pre-exposure prophylaxis in gay and bisexual men: findings from the expanded and extended EPIC-NSW prospective implementation study.

BACKGROUND: Daily pre-exposure prophylaxis (PrEP) is effective in preventing HIV, but few long-term data are available on effectiveness and adherence in real-world settings. Here, we report trends in HIV incidence over 3 years in individuals at high risk who were prescribed PrEP in New South Wales (NSW), as well as adherence before the transition to subsidised PrEP. METHODS: Expanded PrEP Implementation in Communities-New South Wales (EPIC-NSW) was a pragmatic, prospective, single-arm, implementation study of daily, oral PrEP in 31 sites (sexual health clinics, general practices, and a hospital) in NSW, Australia. Eligible participants were HIV-negative adults (aged ≥18 years) who were at high risk of HIV infection as defined in local PrEP guidelines. Participants were prescribed coformulated (once-daily, oral tablet) tenofovir disoproxil fumarate (300 mg) and emtricitabine (200 mg) as HIV PrEP and were followed up with HIV testing, sexually transmitted infection testing, and PrEP dispensing. Originally planned for 3700 participants followed for 1 year, the study was expanded so that all eligible participants in the state could obtain PrEP and extended until publicly subsidised PrEP became available in Australia. The primary outcome was new HIV infection among all participants who were dispensed PrEP at least once and had at least one follow-up HIV test result. Adherence was estimated by medication possession ratio (MPR), defined as the proportion of PrEP pills dispensed in 90 days, assuming daily dosing. This study is registered with ClinicalTrials.gov, NCT02870790. FINDINGS: Between March 1, 2016, and April 30, 2018, we enrolled 9709 participants. 9596 participants were dispensed PrEP, of whom 9448 (98·3%) were gay or bisexual men. Participants were followed up until March 31, 2019, with at least one follow-up HIV test available in 9520 (99·2%) participants. Mean MPR declined from 0·93 to 0·64 from the first to the ninth quarter. There were 30 HIV seroconversions over 18 628 person-years, an incidence of 1·61 per 1000 person-years (95% CI 1·13-2·30). Being younger, living in a postcode with fewer gay men, reporting more risk behaviours at baseline, and having an MPR of less than 0·6 were each univariately associated with increased HIV incidence. In the final year of follow-up, when PrEP was mostly purchased rather than provided free by the study, HIV incidence remained low at 2·24 per 1000 person-years (1·46-3·44). INTERPRETATION: HIV incidence remained low over up to 3 years of follow-up, including during a transition from study-provided to publicly subsidised PrEP. In a setting of affordable PrEP and associated health-care services, very low HIV incidence of 1 to 2 per 1000 person-years can be maintained in gay and bisexual men who were previously at high risk. FUNDING: New South Wales Ministry of Health, Australian Capital Territory Health Directorate, Gilead Sciences.

Renal impairment in a large-scale HIV preexposure prophylaxis implementation cohort.

BACKGROUND: HIV preexposure prophylaxis (PrEP) with fixed-dose tenofovir disoproxil fumarate (TDF) and emtricitabine has been associated with low rates of renal impairment in clinical trials. Large-scale PrEP implementation may result in higher rates, as the prevalence of associated risk factors may be higher than in trial populations. METHODS: A posthoc analysis of EPIC-NSW, a large Australian multicentre PrEP implementation trial for patients at high risk of HIV infection. Participants were eligible for inclusion if they commenced PrEP between 1 March 2016 and 30 April 2018, and had renal function assessed at baseline and at least once more before the censor date. The primary outcome was new-onset renal impairment, defined as an estimated glomerular filtration rate (eGFR) <60 ml/min per 1.73 m2. RESULTS: A total of 6808 participants were eligible for inclusion. Almost all were male (99%), with a median age of 35 years [interquartile range (IQR): 28-44]. Approximately one-quarter (26%) had a baseline eGFR <90 ml/min per 1.73 m2. Over a median follow-up period of 1.2 years (IQR: 0.6-1.7), the rate of renal impairment was 5.8 episodes per 1000 person-years [95% confidence interval (CI): 4.0-7.8]. In multivariable Cox regression, there was a higher risk of renal impairment in participants aged ≥50 years [hazard ratio (HR) 14.7, 95% CI: 5.0-43.3, P < 0.001] and those with an eGFR <90 ml/min per 1.73 m2 (HR 28.9, 95% CI: 6.9-121.9) at baseline. CONCLUSION: In a large-scale implementation study, TDF-containing PrEP was associated with a low risk of renal impairment overall, whereas older patients and those with preexisting renal dysfunction were at substantially increased risk.

Adherence to daily HIV pre-exposure prophylaxis in a large-scale implementation study in New South Wales, Australia.

OBJECTIVES: To examine patterns of long-term pre-exposure prophylaxis (PrEP) adherence and its association with HIV seroconversion in NSW, Australia. DESIGN: Population-based HIV PrEP implementation study. METHODS: Expanded PrEP Implementation in Communities in New South Wales was an open-label study of daily oral PrEP which recruited participants from March 2016 to April 2018. Adherence was measured using dispensing records. PrEP discontinuation was defined as an at least 120-day period without PrEP coverage. Long-term adherence patterns were identified using group-based trajectory modelling. RESULTS: Participants dispensed at least once (n = 9586) were almost all male (98.5%), identified as gay (91.3%), with a median age of 34 years (range: 18-86). Of the 6460 (67.4%) participants who had at least 9 months of follow-up since first dispensing, 1942 (30.1%) discontinued. Among these, 292 (15.0%) restarted later. Four distinct groups were identified ['Steep decline' in adherence (15.8%), 'Steady decline' (11.6%), 'Good adherence' (37.4%), and 'Excellent adherence' (35.2%)]. Older (P < 0.001) and gay-identified (P < 0.001) participants were more likely to have higher adherence, so were those living in postcodes with a higher proportion of gay-identified male residents (P < 0.001). Conversely, those who at baseline reported recent crystal methamphetamine use and had a recent diagnosis of sexually transmitted infection (STI) had lower adherence (P < 0.001). Overall HIV incidence was 0.94 per 1000 person-years (95% confidence interval: 0.49-1.81; n = 9) and was highest in the 'steep decline' group (5.45 per 1000 person-years; P = 0.001). CONCLUSION: : About 15% of participants stopped PrEP during study follow-up and were at increased risk of HIV infection. They were more likely to be younger and report a recent STI or methamphetamine use prior to PrEP initiation.

Barriers and enablers experienced by health care workers in swabbing for COVID-19 in Papua New Guinea: A multi-methods cross-sectional study.

OBJECTIVE: We aimed to identify the barriers and enablers that Health Care Workers (HCWs) in Papua New Guinea experienced in swabbing for COVID-19. METHODS: We conducted a cross-sectional multi-methods study: a qualitative scoping exercise and a telephone survey. The target population was COVID-19-trained HCWs from all provinces of Papua New Guinea. A descriptive analysis of survey responses was conducted alongside a rapid qualitative analysis of interviews and open-ended survey questions. RESULTS: Four thematic areas were identified: human resources, logistics, HCW attitudes and community attitudes. The survey response rate was 70.3% (407/579). Commonly reported barriers to COVID-19 swabbing were insufficient staff trained (74.0%, n = 301), inadequate staffing in general (64.9%, n = 264), insufficient supply of personal protective equipment (60.9%, n = 248) and no cold chain to store swabs (57.5%, n = 234). Commonly reported enablers to swabbing were community awareness and risk communication (80.8%, n = 329), consistent and sufficient supplies of personal protective equipment (67.8%, n = 276), increased surge workforce (63.9%, n = 260) and having a fridge to store swabs (59.7%, n = 243). CONCLUSIONS: A comprehensive community and HCW engagement strategy combined with innovations to improve the supply chain are needed to increase COVID-19 swabbing in Papua New Guinea to reach national testing targets. Investments in increasing numbers of frontline workforce, consistent supplies of PPE, swabs, transport medium, cold boxes and ability to make ice packs, in addtion to establishing regular tranport of specimens from the facility to the testing site will strengthen the supply chain. Innovations are needed to address these issues.

High Levels of Prevention-Effective Adherence to HIV PrEP: An Analysis of Substudy Data From the EPIC-NSW Trial.

BACKGROUND: Preexposure prophylaxis (PrEP) prevents HIV infection but relies on good adherence at times of risk, termed "prevention-effective adherence." Most studies assess adherence without reference to sexual behaviur, making it challenging to determine if poor adherence coincides with HIV risk. SETTING: We examined data from a behavioral substudy of a large-scale PrEP implementation trial in New South Wales, Australia. METHODS: Trial participants completed optional brief quarterly surveys, reporting the number of pills taken and sexual behavior with male partners for each day of the "last full week" before each survey. Condomless sex (CLS) was defined as "higher risk" for HIV when with HIV-positive men with detectable/unknown viral loads or unknown HIV status men. Adequate PrEP protection was defined as ≥4 pills for participants assigned male sex at birth and ≥6 pills for participants assigned female sex at birth (including transgender men). RESULTS: Of 9596 participants dispensed PrEP, 4401 completed baseline and ≥1 follow-up survey. Participants reported on 12,399 "last full weeks": 7485 weeks (60.4%) involved CLS and 2521 weeks (33.7% of CLS-weeks) involved higher risk CLS. There were 103 weeks in which participants did not have adequate PrEP protection and had higher risk CLS: 4.1% of higher-risk CLS weeks (n = 103/2521), 1.4% of all CLS weeks (n = 103/7485), and 0.8% of all observed weeks (n = 103/12,399). CONCLUSIONS: In a large PrEP trial, prevention-effective adherence to PrEP was very high at 99%. Our findings illustrate the importance of measuring pill-taking and sexual behavior in the same period so that prevention-effective adherence can be better estimated.

Substantial Decline in Use of HIV Preexposure Prophylaxis Following Introduction of COVID-19 Physical Distancing Restrictions in Australia: Results From a Prospective Observational Study of Gay and Bisexual Men.

BACKGROUND: In response to the novel coronavirus disease (COVID-19) pandemic, Australia introduced public health and physical distancing restrictions in late March 2020. We investigated the impact of these restrictions on HIV preexposure prophylaxis (PrEP) use among Australian gay and bisexual men (GBM). METHODS: Participants in an ongoing online cohort study previously reported PrEP use from 2014 to 2019. In April 2020, 847 HIV-negative and untested participants completed questionnaires assessing changes in PrEP use as a result of COVID-19 public health measures. Binary logistic multiple regression was used to estimate adjusted odds ratios (aOR) and 95% confidence intervals (95% CI) to compare changes in PrEP use behaviors. RESULTS: Among 847 men, mean age was 44.1 years (SD: 12.7). PrEP use rose from 4.9% in 2015 to 47.2% in 2020. Among those, 41.8% (n = 167) discontinued PrEP use during COVID-19 restrictions. Discontinuing PrEP during COVID-19 restrictions was independently associated with being less likely to have recently tested for HIV (aOR: 0.17; 95% CI: 0.09 to 0.34; P < 0.001) and less likely to report sex with casual partners (aOR: 0.28; 95% CI: 0.14 to 0.54; P < 0.001). CONCLUSIONS: By April 2020, following the introduction of COVID-19 restrictions, GBM dramatically reduced PrEP use, coinciding with a reduction in sexual activity. Longer-term impacts of COVID-19 restrictions on sexual behaviors among GBM need to be monitored because they may foreshadow fluctuations in prevention coverage and risk of HIV infection. Our findings indicate a potential need for clear, targeted information about resumption of PrEP and on-demand optimal dosing regimens in response to ongoing changes in restrictions.

Physical Distancing Due to COVID-19 Disrupts Sexual Behaviors Among Gay and Bisexual Men in Australia: Implications for Trends in HIV and Other Sexually Transmissible Infections.

INTRODUCTION: In March 2020, Australian state and federal governments introduced physical distancing measures alongside widespread testing to combat COVID-19. These measures may decrease people's sexual contacts and thus reduce the transmission of HIV and other sexually transmissible infections (STIs). We investigated the impact of physical distancing measures due to COVID-19 on the sexual behavior of gay and bisexual men in Australia. METHODS: Between April 4, 2020, and April 29, 2020, 940 participants in an ongoing cohort study responded to questions to measure changes in sexual behaviors during the COVID-19 pandemic. Men reported the date they become concerned about COVID-19 and whether they engaged in sexual behavior with regular or casual partners or "fuckbuddies" in the 6 months before becoming concerned about COVID-19 (hereafter referred to as "before COVID-19"), and following the date, they become concerned about COVID-19 (hereafter referred to as "since COVID-19"). Before and since COVID-19 was based on individual participants' own perceived date of becoming concerned about COVID-19. RESULTS: The mean age of was 39.9 years (SD: 13.4). Most participants (88.3%) reported sex with other men during the 6 months before COVID-19. Of the 587 men (62.4%) who reported sex with casual partners before COVID-19, 93 (15.8%) continued to do so in the period since COVID-19, representing a relative reduction of 84.2%. CONCLUSION: Gay and bisexual men in Australia have dramatically reduced their sexual contacts with other men since COVID-19. These behavioral changes will likely result in short-term reductions in new HIV and STI diagnoses. If sexual health screenings are undertaken before resuming sexual activity, this could present a novel opportunity to interrupt chains of HIV and STI transmission.

Prevalence, frequency, and motivations for alkyl nitrite use among gay, bisexual and other men who have sex with men in Australia.

BACKGROUND AND AIMS: Gay, bisexual and other men who have sex with men (GBM) use alkyl nitrites ('poppers') at higher rates than other populations to functionally enhance sexual experiences. Their use has been associated with HIV sexual risk behaviours including receptive anal sex. We investigate the prevalence, frequency, and motivations for poppers use and their relationship with HIV risk. We also discuss the implications of the recent scheduling changes to poppers by the Australian Therapeutic Goods Administration. METHODS: Data were drawn from the Following Lives Undergoing Change (Flux) study, a prospective observational study of licit and illicit drug use among GBM. Between 2014 and 2018, 3273 GBM enrolled in the study. In 2018, 1745 GBM provided data relating to frequency of and motivations for poppers use and were included in this analysis. RESULTS: Median age was 33 years (IQR 25-46) and 801 GBM (45.9%) had used poppers in the previous six months ('recent use'). Among these men, 195 (24.3%) had used them weekly or more frequently. Most recent users (77.4%) reported using poppers for a 'buzz' during sex or to facilitate receptive anal intercourse (60.8%). The majority (57.7%) of HIV-negative men reporting recent poppers use were concurrently taking HIV pre-exposure prophylaxis. Recent poppers use was independently associated with receptive anal intercourse with casual partners (aOR 1.71; 95%CI 1.35-2.16) and chemsex (aOR 4.32; 95%CI 3.15-5.94). Poppers use was not associated with anxiety, depression, or drug-related harms. Only 15.4% of current users indicated they would stop using poppers if they were criminalised; 65.0% said they would 'find other ways' to obtain them. CONCLUSIONS: Poppers are commonly used by Australian GBM to functionally enhance sexual experiences, particularly to facilitate receptive anal intercourse. Few men experienced drug-related harms from poppers use. Regulatory changes must ensure potential harms from popper use are minimised without increasing barriers to access or perpetuating stigma.

Use of HIV Pre-exposure Prophylaxis (PrEP) Associated With Lower HIV Anxiety Among Gay and Bisexual Men in Australia Who Are at High Risk of HIV Infection: Results From the Flux Study.

BACKGROUND: Many gay and bisexual men (GBM) experience HIV anxiety, particularly around condomless anal intercourse. HIV pre-exposure prophylaxis (PrEP) is an effective HIV prevention strategy that may reduce HIV anxiety among GBM. METHODS: The Following Lives Undergoing Change (Flux) Study is a national, online, open-prospective observational study of licit and illicit drug use among GBM in Australia. In 2018, participants responded to newly included items regarding anxiety about HIV transmission. Stratifying GBM as high or low risk as determined by the Australian PrEP Guidelines, we assess whether PrEP use is associated with lower levels of HIV anxiety. Multivariate logistic regression was used to compare factors associated with PrEP use among GBM at high risk (PrEP-eligible) and low risk (PrEP-ineligible) of HIV infection. Results are reported as adjusted odds ratios and corresponding 95% confidence intervals. RESULTS: Among 1547 men, the mean age was 37.1 years (SD 13.1). Men aged 25 years or younger had higher HIV anxiety scores than older men. Among PrEP-eligible men, men who use PrEP reported lower levels of HIV anxiety (adjusted odds ratio = 0.92; 95% confidence interval = 0.87 to 0.99; P < 0.001). No differences were observed on HIV anxiety among PrEP-ineligible men. CONCLUSIONS: Among PrEP-eligible men, PrEP use was independently associated with lower levels of HIV anxiety. In addition to avoiding HIV infection, PrEP use may help reduce anxiety among men at risk of HIV. This feature of PrEP could be promoted as part of demand creation initiatives to increase PrEP uptake.

Biomedical HIV Protection Among Gay and Bisexual Men Who Use Crystal Methamphetamine.

Use of crystal methamphetamine (crystal) among gay and bisexual men (GBM) has been associated with condomless anal intercourse with casual partners (CLAIC) and HIV infection. Pre-exposure prophylaxis (PrEP) and undetectable viral load (UVL) are important biomedical HIV prevention strategies. We investigate the relationship between crystal use and HIV sexual risk behaviours in the context of PrEP and UVL. In 2018, 1367 GBM provided details about crystal use and HIV prevention strategies. Binary logistic regression was used to estimate associations between crystal use and behaviour. Recent crystal use was independently associated with greater social engagement with gay men and having more sexual partners. Crystal use was also independently associated with use of PrEP and UVL among GBM who engaged in CLAIC. Although GBM who used crystal were more likely to have engaged in CLAIC, they were also more likely to use biomedical HIV prevention which mitigates against the risks of HIV infection.