A new study presented at the 2025 European AIDS Clinical Society (EACS) Congress has revealed that more than 50% of HIV cases among migrants in Switzerland are acquired after migration, underscoring the need for better prevention and testing programs targeted at migrant communities.
The research, based on data from the Swiss HIV Cohort Study (SHCS) spanning 2010 to 2024, analyzed 3,490 participants — 1,777 Swiss nationals and 1,713 migrants — excluding individuals with perinatal HIV infections. The findings show a steady rise in the number of migrants joining the cohort, with migrants representing a median of 52% of new participants.
Researchers say this trend reflects Switzerland’s changing demographics and the increasing health relevance of its migrant population.
Majority Diagnosed After Migration
According to the study, 62.1% of migrants were diagnosed with HIV after moving to Switzerland, while 37.9% received their diagnosis before migration.
Among those infected post-migration, the most common transmission routes were:
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Men who have sex with men (MSM): 43.1%
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Female heterosexuals: 27.2%
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Male heterosexuals: 18.9%
Migrants diagnosed after arrival also had significantly lower CD4 counts than Swiss nationals, indicating later detection. The average time from immigration to diagnosis differed by group — six years for male heterosexuals, five for MSM, and two for female heterosexuals.
The study’s authors stressed that distinguishing between new infections acquired in Switzerland and delayed diagnoses of pre-existing infections is vital for crafting more effective public health responses.
Broader Health Implications
Experts warn that late diagnosis not only harms individual health outcomes but also poses serious public health risks, as people unaware of their HIV status are less likely to start treatment early — increasing the likelihood of further transmission.
They called for inclusive, culturally tailored HIV programs that address language barriers, stigma, and healthcare inaccessibility among migrants.
A Europe-Wide Challenge
The Swiss findings mirror broader European trends, where migrants — especially from sub-Saharan Africa and non-EU countries — are disproportionately affected by late HIV diagnoses.
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A UK Health Security Agency report found that 65% of migrant MSM cases were diagnosed after migration.
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A multicountry study published in AIDS Journal revealed that 63% of migrants across nine European nations, including 45% of sub-Saharan Africans, acquired HIV post-migration.
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Eurosurveillance (2024) data also showed that nearly half of new HIV cases in the EU/EEA between 2014 and 2023 involved migrants, with over half (52%) classified as late diagnoses.
Earlier analyses by the European Centre for Disease Prevention and Control (ECDC) further confirmed that migrants from sub-Saharan Africa face the highest risk of late HIV presentation.
Researchers and public health experts agree that these findings highlight an urgent need for targeted HIV screening, community outreach, and early testing initiatives designed to bridge the healthcare gap for migrant populations across Europe.
