Sweden has reduced its HIV incidence and surpassed the UNAIDS 95-95-95 targets, but exogenous infections, particularly among migrants, require renewed focus to maintain progress.
Report: Sweden surpasses the UNAIDS 95-95-95 target: estimating HIV-1 incidence, 2003 to 2022. Image Credit: Rawpixel.com / Shutterstock
The United Nations program on human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS), or UNAIDS 95-95-95 targets, were set by the United Nations to help end the AIDS epidemic by 2025. In a recent study published in the journal Eurosurveillance, a team of researchers from Sweden evaluated the country’s progress towards achieving these goals by analyzing the number of undiagnosed HIV cases and trends in new infections. Sweden had already reached the UNAIDS 90-90-90 target in 2015 and surpassed the 95-95-95 target in 2018.
Background
Since the discovery of HIV/AIDS in 1981, approximately 85 million people have been identified as infected, and statistics from 2022 indicate that close to 39 million individuals are living with HIV. However, with the advent of antiretroviral therapy (ART), individuals with HIV have life expectancies comparable to those of uninfected people.
Sweden has offered free HIV testing and ART since 2004, along with special testing programs for migrants and pregnant women. Most new HIV infections are believed to occur because people with undiagnosed HIV are unaware of the infection and, therefore, do not or cannot take the necessary measures to prevent the spread of the virus.
The UNAIDS target of 95-95-95 aims that by 2025, 95% of the individuals with HIV will be diagnosed, 95% of those diagnosed with HIV will be on ART, and 95% of those undergoing ART will have successful viral suppression.
About the study
The present study aimed to use Sweden’s InfCareHIV database to estimate the incidence of HIV and the number of undiagnosed cases between 2003 and 2022, assess the country’s progress towards achieving the 95-95-95 targets, and identify the areas of prevention that need focus.
The InfCareHIV database contains demographic and clinical information on more than 99% of the individuals living with HIV in Sweden since 2003. It also includes information on biomarkers such as CD4-positive T cell or helper T cell counts, HIV-1 viral load, and genetic information from the resistance tests.
Furthermore, the database contains data on the commencement of ART, viral suppression, transmission mode, country of birth, and immigration for individuals born outside Sweden.
The researchers applied a Bayesian statistical model incorporating multiple biomarkers, such as CD4 T-cell counts and HIV-1 viral load, to estimate the time of infection. They used this model to the information from the InfCareHIV database to estimate the incidence of HIV and the number of undiagnosed cases.
Moreover, by incorporating multiple measurements from previous negative HIV tests, follow-up visits, and immigration dates from individuals not born in Sweden, the model estimated a probabilistic infection time for each individual.
This method allowed the researchers to determine the number of new HIV infections per year and the total number of people living with HIV every year, which helped them account for the number of people who had not been diagnosed.
Furthermore, the study also distinguished between endogenous infections or those acquired after arriving in Sweden, and exogenous infections, acquired before arriving in Sweden, to help assess where the prevention efforts should be focused. The model accounted for uncertainties in estimating infection times, especially among migrants, where the timing of arrival to Sweden plays a critical role. The Bayesian model also adjusted for the underreporting of recently infected but undiagnosed individuals while accounting for uncertainties.
Results
The study found that the incidence of HIV-1 in Sweden had decreased significantly between 2003 and 2022, with notable changes in various transmission categories. Furthermore, after the overall incidence of HIV peaked in 2018, the country saw a steady decline in the incidence of HIV.
The largest reductions were seen in the number of exogenous heterosexual HIV infections, which went from 132 cases in 2018 to 65 in 2021. However, in 2022, the number of exogenous heterosexual infections increased to 139, likely influenced by factors such as lifted travel restrictions after the COVID-19 pandemic and the influx of refugees, including those from the war in Ukraine.
Exogenous transmissions among men who have sex with men also decreased but remained the largest single transmission category in 2021. The proportion of endogenous HIV infections acquired within Sweden decreased from 60.3% in 2003 to 20.7% in 2022.
Despite the decrease in incidence rates, the prevalence of people living with HIV increased in all the transmission categories, indicating longer survival due to ART. The exogenous infections category showed the most significant increase in prevalence between 2003 and 2022.
The proportion of undiagnosed people with HIV was found to decrease overall, with exogenous heterosexual and exogenous men who have sex with men transmission categories showing notable reductions. However, there was an increase in undiagnosed cases in the exogenous heterosexual category in 2022, further supporting the need for ongoing targeted prevention efforts.
Furthermore, the findings confirmed that Sweden had met the UNAIDS 95-95-95 targets in 2018, with 95% of the individuals with HIV having been diagnosed, 99% of those diagnosed with HIV undergoing ART, and 98% of those on ART showing successful viral suppression.
Conclusions
In conclusion, the findings showed that Sweden had made significant progress in reducing the incidence of HIV-1 and achieving the UNAIDS 95-95-95 targets. However, critical challenges remain in diagnosing certain groups, especially those involving exogenous infections. The study emphasizes that targeted efforts, particularly among migrants and those recently arriving in Sweden, are crucial to maintaining these success rates. The researchers believe that continued prevention, testing, and treatment efforts are essential for maintaining and improving these success rates.
In addition to the UNAIDS targets, the study also highlights the importance of ensuring access to preventive measures, such as pre-exposure prophylaxis (PrEP), which is currently limited in Sweden to certain groups, such as men who have sex with men but could be expanded to migrant populations to further reduce HIV transmission.
Journal reference:
- Lundgren, E., Locke, M., Romero-Severson, E., Dimitrijevic, M., Axelsson, M., Andersson, E., Carlander, C., Brännström, J., Norrgren, H., Mansson, F., Elvstam, O., Gisslén, M., Fohlin, L., Sönnerborg, A., Albert, J., & Leitner, T. (2024). Sweden surpasses the UNAIDS 95-95-95 target: estimating HIV-1 incidence, 2003 to 2022. Eurosurveillance, 29, 42, DOI:10.2807/1560-7917.ES.2024.29.42.2400058, https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2024.29.42.2400058