Non-communicable disease risk factors in patients with major depressive disorders.

This study assessed hepatitis A immunity among men who have sex with men in New South Wales during a 2017–2018 outbreak, to identify immunity gaps and inform outbreak control. We triangulated four data sources: serological testing of 409 residual sera collected from males undergoing syphilis testing between August and October 2017, a survey of all 17 publicly funded sexual health clinics, a behavioural survey of 50 men at a sex-on-premises venue, and community survey data from 2018 to 2019 ( = 5,924). Overall serological immunity was 62.8% (257/409) and increased significantly with age, from 50.0% in men aged under 26 years to 79.0% in those aged over 45 years ( for trend <0.001). Clinic-based immunity estimates were higher (74.5%), and self-reported vaccination in community surveys was 74.3% in 2018 and 76.8% in 2019. Vaccination coverage was lower in bisexual than gay-identifying men (61.8% vs. 77.2%;  < 0.001). Immunity gaps were also identified among men less connected to the gay community and those born outside Australia. These findings informed targeted vaccination and community messaging, and demonstrated the value of multisource immunity assessment for outbreak response and prevention. Hepatitis A virus (HAV) is commonly transmitted primarily through the faecal–oral route, often via contaminated food or water, or through close person-to-person contact. Infection is preventable through vaccination. While HAV incidence has declined in many high-income countries due to improved sanitation and childhood vaccination in some regions, susceptible populations remain at risk of outbreaks, particularly where immunity is low []. In recent years, multiple HAV outbreaks have been reported among men who have sex with men (MSM) across Europe [–] and the USA [, ], with molecular evidence linking many cases to the same internationally circulating genotype IA strains. These outbreaks demonstrate how HAV can rapidly spread through globally connected MSM networks and highlights the importance of understanding population-level immunity in these groups.