Estimates of the HIV undiagnosed population in Belgium reveals higher prevalence for MSM with foreign nationality and for geographic areas hosting big cities

Abstract

Introduction Increasing our knowledge on geographic areas and key populations most affected by HIV is essential to improve prevention and care and to ensure a more focused HIV response. Here, we estimated the prevalence of undiagnosed HIV infections in Belgium and its distribution across geographic areas and exposure groups. Methods We used surveillance data on newly diagnosed HIV cases and a previously developed back‐calculation model to estimate number and prevalence rates (per 10000) of undiagnosed HIV infections by exposure group at national and subnational levels. Belgium consists of three regions: Flanders, Brussels‐Capital Region and Wallonia. We produced estimates for Brussels‐Capital Region and Wallonia. For Flanders, we produced estimates for two sub‐regional areas: the province of Antwerp and the other provinces, because Antwerp is the second largest city after Brussels. Population sizes were determined using data from the Belgian Statistical Office and surveys on sexual behaviour and drug use. Results In Belgium, in 2015, an estimated 2818 (95% confidence interval: 2494 to 3208) individuals were living with undiagnosed HIV, that is, 15% of individuals living with HIV. The Brussels‐Capital Region and the province of Antwerp, which host the two biggest cities, accounted for ~60% of the undiagnosed infections, and had the highest undiagnosed prevalence rates per 10000: 12.0 (9.4 to 15.3) and 7.4 (5.6 to 9.8) respectively. Individuals with foreign nationality accounted for 56% of the total number of undiagnosed infections, and were the most affected populations in all areas in terms of undiagnosed prevalence rates. Specifically, men who have sex with men (MSM) with non‐European nationality were the most affected population in the province of Antwerp (853.4 (408.2 to 1641.9) undiagnosed infections per 10000), the Brussels‐Capital Region (543.9 (289.1 to 1019.1)), and the other provinces of Flanders (691.7 (235.5 to 1442.2)), while in Wallonia, it was heterosexual women with Sub‐Saharan African nationality (132.2 (90.6 to 178.5)). Conclusions Geographic areas hosting the biggest cities in Belgium accounted for the vast majority of undiagnosed HIV infections and individuals with foreign nationality were the most affected, especially MSM with non‐European nationality. This should be accounted for when tailoring prevention and testing programs. Furthermore, MSM with foreign nationality require more attention in Belgium, and certainly more generally in Europe.

The role of mobility in sexual risk behaviour and HIV acquisition among sub-Saharan African migrants residing in two European cities

“…This may be surprising given that prenatal HIV screening offers constitute HIV testing opportunities for women in both countries. However, a recent study using mathematical modelling in Belgium showed that indeed women of sub-Saharan African origin have a high risk of being undiagnosed [59]. Migration status may be one of the structural factors impeding access [60,61], but future research should explore this finding in more detail.…”

Monitoring progress towards the first UNAIDS 90-90-90 target in key populations living with HIV in Norway

“…Overall point estimates of the proportion undiagnosed in 2018 using the ECDC modelling tool ranged from 7.1% (355 undiagnosed infections) using default model assumptions for CD4 distribution, to 10.2% (520 undiagnosed infections) with the Danish CD4 proxy, which is amongst the lowest in Europe, and comparable to estimates from neighbouring Denmark and Sweden [13,15,41,42]. National surveillance data and clinical data from the capital, Oslo, support that there is a low proportion undiagnosed in Norway, with a decreasing total number of first-time diagnoses, low proportion of late diagnoses and high proportion achieving viral suppression [17,27].…”

Development and Evaluation of an HIV-Testing Intervention for Primary Care: Protocol for a Mixed Methods Study

“…The HIV European Research on Mathematical Modeling and Experimentation of HIV Testing in Hidden Communities (HERMETIC) project applies a mathematical model for routine HIV-surveillance data to calculate the size and proportion of these undiagnosed HIV-infected populations. Modeling results obtained using a back-calculation method [ 5 ] for Belgium indicate that almost 2818 people living with HIV remained undiagnosed in 2015, corresponding to a prevalence rate of 4.1 undiagnosed persons per 10,000 [ 6 ]. The most affected populations were non-Belgian MSM (almost 264 undiagnosed persons per 10,000), SAMs with a higher proportion among women (about 173 per 10,000) than among men (about 93 per 10,000), and Belgian MSM (about 55 per 10,000) [ 6 ].…”

“…Modeling results obtained using a back-calculation method [ 5 ] for Belgium indicate that almost 2818 people living with HIV remained undiagnosed in 2015, corresponding to a prevalence rate of 4.1 undiagnosed persons per 10,000 [ 6 ]. The most affected populations were non-Belgian MSM (almost 264 undiagnosed persons per 10,000), SAMs with a higher proportion among women (about 173 per 10,000) than among men (about 93 per 10,000), and Belgian MSM (about 55 per 10,000) [ 6 ]. While Belgian HIV-testing rates are relatively high and cost-effective with 1.25 new HIV diagnoses per 1000 tests [ 4 , 7 ], these estimates of undiagnosed HIV infections indicate that current HIV-testing strategies fail to reach all people at risk of infection in a timely manner.…”

“…In the preparatory phase, a detailed contextual analysis of the problem within the local Flemish context was conducted (see step 1 in Figure 1 ). The aforementioned modeling results [ 6 ] were triangulated with multiple data sources [ 21 ], such as behavioral surveys and an expert meeting for validation and to gain further in-depth insight. The results of a mixed research synthesis on HIV testing in European general practices [ 11 ] provided additional guidance.…”