A systematic review of post-migration acquisition of HIV among migrants from countries with generalised HIV epidemics living in Europe: mplications for effectively managing HIV prevention programmes and policy

Estimates of probable country of infection and/or estimates of incident infection were found in 18 of the 27 papers selected for systematic review. In most of the papers, the study population included people from countries not considered to have a generalised HIV epidemic, but data were disaggregated which allowed reviewers to perform data extraction and compare data across countries. The estimates varied both within countries and across Europe, and covered a range of subgroups, including men who have sex with men (MSM) as well as heterosexuals. Table 4 shows the proportion of infections acquired among sub Saharan Africans post–migration in France, Netherlands, Switzerland and the UK. Table 5 shows infections acquired post-migration among individuals from the Caribbean and Asia in Italy, Netherlands, Switzerland and the UK.

While the generilisability and validity of all these papers were medium or high, there are some limitations to the data presented (Table 3). Data estimating the proportion of post-migration HIV acquisition from cross sectional studies in France, Italy, Switzerland and the UK relied on samples that were either very small [12] or were reported to be possibly biased and unrepresentative of the wider population from which the samples were drawn [13‐15]. Estimates from The Netherlands were derived from mathematical models. The authors provided very little information about the data used to source the models nor did they discuss the consequent limitations such data placed on the models [16, 17].

Using a new method to ascertain likely country of HIV infection, the UK recently published estimates of place of HIV acquisition among 10,612 heterosexual migrants (9065 of black-African ethnicity) diagnosed with HIV in the UK between 2004 and 2010 [18]. The authors used CD4 at diagnosis to estimate year of infection for each of the adults in their study population and taking into account the variable “Year of Migration”, assigned probable place of HIV acquisition. The CD4-cell based method estimated that 33 % of the study population (26 %-39 %) acquired HIV while living in the UK, three times higher than national estimates of HIV based on clinic reports (11 %). The study also found that the proportion of persons who had acquired their HIV while living in the UK had increased from 24 % (16-39 %) in 2004 to 46 % (31 %-50 % in 2010 (p < 0.01). Similar analysis performed at a later point by the same authors estimated the increase among black African heterosexuals to be from 9.1 % in 2002 to 37 % in 2011 (p < 0.01), however this analysis included data based on clinical reports [19].

The authors discuss two major limitations with this method. First, the method cannot take into account travel (including vacations back to the country of origin) post-migration. Second, the method relies on key variables (CD4 counts, date of arrival and country of birth) and therefore it cannot be applied if these data are missing.

Fourteen studies examined sexual activity of people after they migrated to Europe (Table 2). Most studies used molecular epidemiology to describe the distribution of non-B subtypes and HIV transmission networks, and in so doing provide estimates of sexual mixing. These studies show that non-B subtypes are prevalent among people born within and outside Europe: in Switzerland, the proportion of non-B subtype virus increased from 22 % in 1996 to 33 % in 2009 [20]; Holguin et al. (2007) [21] found that 53 % of migrants and 14 % of native Spaniards in their study in Grand Canary were infected with non-B strains; Snoeck et al. (2002) reported a small number of non-B subtypes originated in Belgium (16 %) [22]; in Italy Tramuto et al. (2013) estimate that less than one in ten Italian-born individuals in their study were living with non-B HIV-1 subtypes [23]. More detailed analysis from Lai et al. (2013) showed that country of origin was independently associated with the probability of patients being detected in epidemiological clusters, although patients from countries with a generalised epidemic were less likely to be detected than those from Italy or South America [24]. Rivas et al. (2013) provide some evidence of sexual mixing by reporting a small proportion of B subtypes (3.3 %) among migrants from sub Saharan Africa living in an area of Spain [25].

Elford et al. (2007) [26] state that 80 % of black African heterosexuals reported sexual partners of the same ethnicity and van Veen et al. (2009) [27] found that 41 % of their sample had partners with different ethnicity (15 % with Dutch partners). Similarly Marisciano et al. (2013) reported that 50 % of men and 47 % of women had partners from a different country although most were from another African country [28].

In a cross sectional survey examining sexual behaviour among Surinamese and Antillean migrants in the Netherlands [29], the authors describe travel patterns of migrants and provide estimates of sexual mixing for a population they classified as having the potential to provide a transmission “bridge” between the Caribbean and The Netherlands. Those having unprotected sex in both countries, the so-called “bridge population”, reported partners of a different ethnicity less often than those in moderate or low risk groups (42 %, 59 % and 66 % respectively) [29].

Twenty-four countries responded to the survey (response rate: 80 %). Five countries reported having data on sexual transmission of HIV among migrant communities. Denmark and Germany provided some contextual information about sexual transmission of HIV, but were unable to provide estimates of the proportion of migrants acquiring their HIV post-migration. The Netherlands provided grey literature and peer reviewed papers (subsequently included in the literature review) showing within-country sexual transmission among migrant communities. The most specific data came from Norway (14 % of 152 migrants diagnosed with HIV in 2011 were thought to have acquired their HIV infection post-migration) and the UK, (see Rice et al.[18]).

The remaining member state respondents did not provide data on, or estimates of, sexual transmission of HIV among migrant communities.