26th International AIDS Conference 2026 in Rio de Janeiro
Article by Marlon Gattiker

A study from the Pulse Project, presented at AIDS 2026 in Rio de Janeiro by Haoyi Wang (Maastricht University), investigated how cross-border travel affects sexual risk behaviour and HIV/STI prevalence among young gay and bisexual men (MSM) in South-East Asia. Over 3,000 MSM under the age of 25 from Cambodia, Laos, Malaysia and Thailand were surveyed.

The study population faces significant structural disadvantages: over half are unemployed, nearly two-thirds live on less than 150 US dollars a month, and around 44 per cent report symptoms of depression. Only a third have ever been tested for HIV.

Around 16 per cent of respondents had travelled across borders at least once in the past six months – Thailand was by far the most common destination, regardless of country of origin. Of these travellers, 29 per cent stated that they had engaged in at least one of four particularly high-risk behaviours during their trip: unprotected anal sex (22 per cent), receiving sex in exchange for payment (6.7 per cent), paying for sex (‘sex tourism’, 7.3 per cent) or chemsex (2.7 per cent).

The key finding: those who engaged in any of these behaviours whilst travelling consistently had higher rates of HIV and STIs than non-travellers or travellers who did not engage in such behaviour – for example, in the case of syphilis, chlamydia, and hepatitis B and C. Particularly striking was the fact that those who travelled abroad for chemsex had a syphilis prevalence of over 30 per cent.

A gap in access to prevention measures is also evident precisely where it is most painful: whilst travellers engaging in high-risk behaviour were comparatively well-informed about PrEP, they were the least likely to use it (6 per cent current use) and discontinued it more often than average. Wang refers to a ‘PrEP cascade that fails precisely in the group at highest risk’.

The analysis also shows that structural factors significantly increase the risk of such behaviour: employment, previous experience of sex work and, above all, experiences of sexual violence – forced sex increased the likelihood of risky behaviour whilst travelling by a factor of eleven. Experiences of bullying in the past 12 months were also a strong risk factor.

Wang’s conclusion: National HIV programmes are almost universally strictly aligned with national borders. As soon as young MSM cross a border, they often lose access to testing, PrEP and counselling – precisely at the moment when their risk increases. The solution, therefore, lies not in better national programmes, but in programmes designed with a cross-border perspective.

Although the study relates to South-East Asia, the underlying issue is transferable: Swiss MSM travelling abroad for holidays, dating apps or chemsex also encounter gaps in PrEP and testing provision outside the country’s borders. The study highlights the importance of travel-related counselling and low-threshold, cross-border access to prevention services.

Source: Wang, H. “When Sexual Health Prevention and Care Ends at the Border: Cross-border Sexual Mobility, HIV and STI burdens, and PrEP cascades Among Young MSM in Southeast Asia.” Presented at the 26th International AIDS Conference (AIDS 2026), Rio de Janeiro, 26–31 July 2026. HaSH#Lab, Maastricht University.