HIV

1. Key messages

2. New diagnoses of HIV infections in 2023

In 2023, 665 new diagnoses of HIV infections were made in Belgium (5.7 new diagnoses per 100.000 inhabitants, or on average 1.8 cases a day). Among those, 70% were men. 76% of the HIV infections were diagnosed in people aged 20-49.

New HIV diagnoses have increased for 3 consecutive years (2021-2023)

The number of new HIV diagnoses has increased by 13% in 2023 compared to 2022. The total number of new HIV diagnoses is now similar to the last pre-Covid year (-1.3% compared to 2019).

Between the start of the epidemic in the early 80s and the end of 2023, a total of 31,770 persons were diagnosed with HIV, and a total of 5,656 cases of AIDS were reported.

Brussels has a higher diagnosis rate compared to the rest of Belgium

In 2023, of the 665 newly diagnosed persons, 220 were resident in the Brussels-Capital Region, 283 in the Flemish Region, 153 in the Walloon Region, and 9 were residing abroad.

When accounting for the number of inhabitants, the incidence rates in the Flemish Region (max 8 for 100,000 inhabitants in Antwerp district) and in the Walloon Region (max 9/100,000 in Arlon district) are comparable, while the rate in the Brussels Capital Region is much higher (18/100,000). This difference is not surprising since a higher HIV prevalence is a common phenomenon in a big city. The Brussels Capital Region can indeed be considered a big city - with the socio-cultural characteristics of an urban context – while the two other regions mix rural, semi-urban, and urban contexts.

The slight increase in new diagnoses was observed in all three regions from 2021 to 2023

The increase in newly diagnosed people from 2021 onwards observed at national level is mirrored in all three regions, following a decline over the previous decade. This recent increase is particularly marked in the Brussels-Capital Region.

Diversification in the 2-key populations in Belgium

The HIV epidemic in Belgium mainly affects two populations: men who have sex with men (MSM), mostly of Belgian nationality, and men and women who have contracted the virus through heterosexual relations, mainly from sub-Saharan Africa.

However, among both MSM and heterosexuals, the distribution of nationalities changes significantly over time. Among people infected through heterosexual contact, the share of people of sub-Saharan nationality is declining (49% in 2014 to 43% in 2023). The number of diagnoses among heterosexuals has risen by 13% in 2023 compared with 2022. This increase is greater among women of Belgian and other European nationalities (+19% and +23% respectively vs. 2022), as well as men from sub-Saharan Africa and Europe (+33% and +49% vs. 2022). 

In 2023, 297 new HIV diagnoses were made among MSM; this represents a 16% increase on 2022. Although the number of new diagnoses is finally declining in the 20-29 age group after a significant rise (+34% between 2021 and 2022), there has been a particularly sharp increase in the 30-39 age group over the past 2 years. An increase of 14% is also observed among MSM of Belgian nationality compared with 2022; they accounted for 48% of HIV diagnoses among MSM in 2023; 18% had another European nationality and 13% had a Latin American nationality.

Close to 20,000 persons were living with HIV in Belgium in 2023

By the end of 2023, an estimated 18,690 individuals were living with HIV in Belgium. Among them, 93% had received a diagnosis, and of those diagnosed, 95% were undergoing antiretroviral treatment.

More than a thousand people in Belgium live with an undiagnosed HIV infection

In 2023, Sciensano estimated the number of people living with undiagnosed HIV [1] based on a tool developed by ECDC [2]. It is estimated that 1325 people living with HIV in Belgium were unaware of their HIV status. However, these estimates should be interpreted with caution given the significant uncertainty surrounding the estimates for the last 3 years derived from this model. Based on the ECDC tool, the number of people living with undiagnosed HIV in Belgium appears to have been steadily declining since 2011.

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HIV Surveillance - Sciensano

Background

Transmission of HIV

Sexually transmitted infections (STIs) such as human immunodeficiency virus (HIV) are spread primarily through person-to-person sexual contact. Additionally, HIV can be transmitted through blood products and tissue transfer, and from mother to child during pregnancy or breastfeeding.

HIV can be present without symptoms, which can facilitate transmission. It is one of the most serious communicable diseases in Europe. Infection with the virus can, if antiretroviral treatment (ART) is not initiated, lead to serious morbidity (Acquired Immunodeficiency Syndrome (AIDS)) and requires life-long treatment.

HIV is an avoidable infection since the transmission is largely preventable by behavioural measures (safe sex, safe injection). Therefore HIV incidence in a defined population is an indicator of the success/failure of control strategies. Since 2017, the use of pre-exposure prophylaxis to HIV (PrEP) is reimbursed in Belgium.

Surveillance of HIV in Belgium

The epidemiological surveillance of HIV in Belgium dates from 1985 and is carried out by Sciensano on the basis of the registration of new HIV diagnoses. These data are reported by the seven AIDS reference laboratories that perform all confirmations of positive HIV screening tests. In addition to recording the number of newly diagnosed HIV positive persons, the laboratories also collect basic epidemiological data on sex, age, nationality, probable route of infection, and clinical stage at the time of diagnosis. Sciensano also collects data on the people living with HIV (PLWH) in Belgium (HIV cohort data) from the AIDS reference laboratories and the HIV reference centres.

Besides the newly diagnosed cases, Sciensano also estimates the number of people living with HIV: those who have not yet been diagnosed [1] and those living with a diagnosed infection. To estimate the undiagnosed population an instrument developed by the European Center for Disease Prevention and Control (ECDC), called the ECDC HIV Modeling Tool [2] is used. HIV cohort data are used to estimate the number of people living with a diagnosed infection.

ECDC and the WHO Regional Office for Europe jointly coordinate HIV/AIDS surveillance in Europe [3]. The international comparability has some limitations since the national surveillance systems differ in levels of underreporting and reporting delay.

Definitions

New HIV diagnoses

A new HIV diagnosis is defined as a first HIV diagnosis. People, mainly foreigners, with an HIV diagnosis or in care for HIV in another country before their diagnosis was confirmed in Belgium are treated separately. People with known HIV infection do not represent a population that could have benefited from prevention measures in Belgium and are then presented separately. More information on them can be found in the annual epidemiological report.

HIV/AIDS

HIV infection and AIDS are the acronyms of "Human Immunodeficiency Virus" (HIV) infection and "Acquired Immune Deficiency Syndrome" (AIDS). Initial HIV infection is most often asymptomatic, while people may experience influenza-like symptoms. This is followed by a prolonged period with no symptoms. If the infection progresses, it interferes more with the immune system, increasing the risk of developing infections such as tuberculosis, as well as other opportunistic infections, and tumours which are rare in people who have a normal immune function. These late symptoms of infection are referred to as AIDS. Since the late 1990s, efficient antiretroviral treatment exists that can control the progression of the disease.

References

[1] Epidémiologie du VIH en Belgique. Situation au 31 décembre 2023. Bruxelles: Sciensano; 2024. https://www.sciensano.be/en/biblio/epidemiologie-du-vih-en-belgique-situation-au-31-decembre-2023

[2] European Centre for Disease Prevention and Control. HIV Modelling Tool. 2015. https://www.ecdc.europa.eu/en/publications-data/hiv-modelling-tool

[3] European Centre for Disease Prevention and Control/WHO Regional Office for Europe. HIV/AIDS surveillance in Europe 2024 – 2023 data. Stockholm: ECDC; 2024. https://www.who.int/europe/publications/i/item/9789289061551

Please cite this page as: Sciensano. Communicable Diseases: HIV, Health Status Report, 16 Jan 2025, Brussels, Belgium, https://www.healthybelgium.be/en/health-status/communicable-diseases/hiv-and-other-sexually-transmitted-infections