Do sub-Saharan African migrants in Europe risk acquiring HIV when they travel abroad?

Image: Domizia Salusest |

People from sub-Saharan Africa who are now settled in Europe put themselves at some risk of acquiring HIV in their country of residence and when they travel abroad, whether to other parts of Europe or to Africa, according to a study published in PLOS ONE. Dr Christiana Nöstlinger of Antwerp and Professor Sónia Dias of Lisbon led a study of 1508 sub-Saharan migrants in Belgium and Portugal which found that those who travel tend not to use condoms regularly in their country of residence or in the countries they visit, potentially putting them at risk of HIV.

Sub-Saharan African migrants in Europe are estimated to account for 53% of people with HIV who were born outside Europe. Belgium and Portugal were chosen for this study because both have historical colonial links to Africa that affect current migration patterns. These include Belgium’s links to the Democratic Republic of Congo and Portugal’s links to Angola and Mozambique. In Belgium, recent surveillance data show that 30% of newly diagnosed people were sub-Saharan Africans, while in Portugal 18% of newly diagnosed people were born in sub-Saharan Africa.

This study aimed to explore risky sexual behaviour (specifically, sex without condoms) and HIV-acquisition among African migrants living in Belgium and Portugal and to find out if travel has an impact on their risk of sexually acquiring HIV.



Studies aim to give information that will be applicable to a large group of people (e.g. adults with diagnosed HIV in the UK). Because it is impractical to conduct a study with such a large group, only a sub-group (a sample) takes part in a study. This isn’t a problem as long as the characteristics of the sample are similar to those of the wider group (e.g. in terms of age, gender, CD4 count and years since diagnosis).

linkage to care

Refers to an individual’s entry into specialist HIV care after being diagnosed with HIV. 


In a bacteria culture test, a sample of urine, blood, sputum or another substance is taken from the patient. The cells are put in a specific environment in a laboratory to encourage cell growth and to allow the specific type of bacteria to be identified. Culture can be used to identify the TB bacteria, but is a more complex, slow and expensive method than others.

Undetectable = Untransmittable (U=U)

U=U stands for Undetectable = Untransmittable. It means that when a person living with HIV is on regular treatment that lowers the amount of virus in their body to undetectable levels, there is zero risk of passing on HIV to their partners. The low level of virus is described as an undetectable viral load. 

People from migrant communities were involved in the study in both Portugal and Belgium. They identified the venues where potential participants might be found including bars, community associations, African organisation events, shops, and public places such as squares, parks and street corners.

In total, 1508 sub-Saharan migrants were recruited, and were divided into two parts for the study: those who had travelled since settling in their host country and those who had not. The researchers refer to these two groups as ‘travellers’ and ‘non-travellers’ respectively.

The sample was split evenly between the two countries. Men made up 58% of the total, half of the participants were aged between 30 and 49 years, and around a third were younger. Portugal had a larger proportion of older participants than Belgium. The majority of participants had completed secondary education, but Belgium had a larger proportion with higher education. More Portuguese participants were unemployed. Half of the sample overall have been living in the host country for more than ten years, however this proportion was larger among the Portuguese participants. Fourteen percent overall were of undocumented status, but this proportion was larger in Belgium than in Portugal.

Participants were tested for HIV and 5% (75 individuals) tested positive; overall, 39% had never previously tested for HIV.

The findings show that many migrants from sub-Saharan Africa are mobile after settling in their host countries. Two-thirds of all participants had travelled to other countries after having settled in the study country. Of these, 41% had travelled to African and European countries, one quarter had travelled only to Africa, and one third had travelled only to European countries. People who travelled were significantly older than those who did not, more likely to be married or in a stable relationship, to have completed higher education, to be employed, to have lived in the host country for more than ten years, and to have regular immigration status.

"The findings highlight a need for HIV prevention in the context of having sex abroad, especially among older and long-time resident migrants."

In terms of sexual behaviour, travellers reported more frequently than non-travellers (70% vs 63%) that their last sexual intercourse was without condoms. No significant differences were found between travellers and non-travellers about having regular or casual partners, origin of last partner (approximately three-quarters overall were African), number of sexual partners during the last year, or HIV status.

Overall, people who do not use condoms in their country of residence generally do not use condoms in countries that they visit. About two thirds of the travellers (63%) in the sample did not use a condom when having sex abroad and 71% did not use a condom when having sex in their country of residence.

Concerning the 75 HIV-positive participants, 47 travelled abroad, of whom 25 had intercourse abroad. Four of the 25 used a condom and 21 did not. The study identified 28 HIV-positive non-travellers. Of these, 22 said that their last intercourse was in their host country. Half of them used a condom in their last intercourse in the host country while the remaining half did not.

These findings highlight a need for HIV prevention in the context of having sex abroad, especially among older and long-time resident migrants. The researchers say that this might be achieved through the promotion of HIV testing among mobile populations, and that sexual health promotion should incorporate specific advice, such as reinforcing condom promotion when travelling. Newer prevention methods such as PrEP, which so far has not been taken up by this group, should also be promoted. They conclude by saying that greater efforts should be made to reduce the proportion of undiagnosed HIV among mobile and migrant populations and ensure their linkage to care.

The study does have limitations, and these are addressed or implied by the authors. The researchers do not include any data on PrEP use or awareness of U=U, other than to acknowledge a relative lack of awareness. And although the participants’ backgrounds were from different parts of Africa and thus from different cultural traditions, the researchers did not explore culture-specific norms that might affect their sexual behaviours. Indeed the African migrant community representatives advised the researchers against asking questions on specific sexual topics including type of sex (for example, vaginal or anal intercourse) and gender of sexual partners. The authors state that behavioural information of this kind would be interesting to investigate.


Dias S et al. The role of mobility in sexual risk behaviour and HIV acquisition among sub-Saharan African migrants residing in two European cities. PLOS ONE 15: e0228584 (open access), February 2020.