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Abstract

BACKGROUND

The global goal to end the AIDS epidemic cannot be achieved without estimates of incidence and undiagnosed infection.

AIM

We aimed to estimate the timing of HIV transmission events and the number of people unaware of their diagnosis in Scotland, by mode of acquisition and migrant status.

METHODS

Surveillance data from Scotland’s national HIV diagnosis database (1981–2022) linked to death and migration data was entered into the HIV Platform tool of the European Centre for Disease Prevention and Control, to back-calculate HIV incidence while imputing missing data and adjusting for reporting delay.

RESULTS

We estimated 8,235 HIV transmission events between 1980 and 2022 among people living in Scotland, with an 80% reduction from 2010 to 2021 (258 to 52 events). Excluding people diagnosed outside Scotland, we estimated 4,854 (95% confidence interval (CI): 4,637–5,080) people living with HIV at the end of 2021, of whom 8.2% (396/4,854) were undiagnosed. Stratified estimates of this proportion were 6.9% for gay, bisexual and other men who have sex with men, 7.0% for people who inject drugs, 12.6% and 12.4% for heterosexuals born and not-born in the United Kingdom (UK), respectively. Including people first diagnosed with HIV outside Scotland, the overall proportion undiagnosed was 6.1% (396/6,444).

CONCLUSION

Scotland is on track to meet the United Nations' diagnosis target of 95% by 2025, with the World Health Organization target of a 75% incidence reduction met since 2010. To reduce further transmission, expanded HIV testing and prevention services are necessary to better reach at-risk heterosexual individuals.

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2025-09-11
2026-03-10
/content/10.2807/1560-7917.ES.2025.30.36.2500164
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References

  1. World Health Organization (WHO). Global health sector strategies on, respectively, HIV, viral hepatitis and sexually transmitted infections for the period 2022-2030. Geneva: WHO; 2022. Available from: https://www.who.int/publications/i/item/9789240053779
  2. World Health Organization (WHO). HIV statistics, globally and by WHO region, 2025. Epidemiological fact sheet. Geneva: WHO; 2025. Available from: https://cdn.who.int/media/docs/default-source/hq-hiv-hepatitis-and-stis-library/who-ias-hiv-statistics_2025-new.pdf
  3. European Centre for Disease Prevention and Control (ECDC). Progress towards reaching the Sustainable Development Goals related to HIV, viral hepatitis, sexually transmitted infections and tuberculosis in the EU/EEA: 2024 progress report. Stockholm: ECDC; 2025. Available from: https://www.ecdc.europa.eu/sites/default/files/documents/hiv-tuberculosis-hepatitis-sustainable-development-goal-progress-2024.pdf
  4. Lundgren E, Locke M, Romero-Severson E, Dimitrijevic M, Axelsson M, Andersson E, et al. Sweden surpasses the UNAIDS 95-95-95 target: estimating HIV-1 incidence, 2003 to 2022. Euro Surveill. 2024;29(42):2400058.  https://doi.org/10.2807/1560-7917.ES.2024.29.42.2400058  PMID: 39421951 
  5. Health Protection Scotland (HPS). Implementation of HIV pre-exposure prophylaxis in Scotland: first year report. Glasgow: HPS; 2019. Available from: https://www.lothiansexualhealth.scot/wp-content/uploads/2020/03/HIV_PrEP_report-2019-22022019.pdf
  6. Nandwani R, Estcourt CS, Hutchinson SJ, et al. Ending HIV transmission in Scotland by 2030. Edinburgh: Scottish Government; 2022. Available from: https://www.gov.scot/publications/ending-hiv-transmission-scotland-2030
  7. Scottish Government. Ending HIV transmission in Scotland by 2030: HIV transmission elimination delivery plan, 2023-26. Edinburgh: Scottish Government; 2024. Available from: https://www.gov.scot/publications/ending-hiv-transmission-scotland-2030-hiv-transmission-elimination-delivery-plan-2023-26
  8. Public Health Scotland (PHS). HIV in Scotland. Update to 31 December 2022. Glasgow: PHS; 2023. Available from: https://publichealthscotland.scot/publications/hiv-in-scotland/hiv-in-scotland-update-to-31-december-2022
  9. Presanis AM, Harris RJ, Kirwan PD, Miltz A, Croxford S, Heinsbroek E, et al. Trends in undiagnosed HIV prevalence in England and implications for eliminating HIV transmission by 2030: an evidence synthesis model. Lancet Public Health. 2021;6(10):e739-51.  https://doi.org/10.1016/S2468-2667(21)00142-0  PMID: 34563281 
  10. Prosser AT, Tang T, Hall HI. HIV in persons born outside the United States, 2007-2010. JAMA. 2012;308(6):601-7.  https://doi.org/10.1001/jama.2012.9046  PMID: 22820630 
  11. Pavis S, Morris AD. Unleashing the power of administrative health data: the Scottish model. Public Health Res Pract. 2015;25(4):e2541541.  https://doi.org/10.17061/phrp2541541  PMID: 26536503 
  12. European Centre for Disease Control and Prevention (ECDC). HIV Platform tool. [Software application]. Version 2.0.0. Stockholm: ECDC; 2021. Available from: https://www.ecdc.europa.eu/en/publications-data/hiv-platform-tool
  13. Sweeting MJ, De Angelis D, Aalen OO. Bayesian back-calculation using a multi-state model with application to HIV. Stat Med. 2005;24(24):3991-4007.  https://doi.org/10.1002/sim.2432  PMID: 16320278 
  14. Birrell PJ, Gill ON, Delpech VC, Brown AE, Desai S, Chadborn TR, et al. HIV incidence in men who have sex with men in England and Wales 2001-10: a nationwide population study. Lancet Infect Dis. 2013;13(4):313-8.  https://doi.org/10.1016/S1473-3099(12)70341-9  PMID: 23375420 
  15. van Sighem A, Nakagawa F, De Angelis D, Quinten C, Bezemer D, de Coul EO, et al. Estimating HIV incidence, time to diagnosis, and the undiagnosed HIV epidemic using routine surveillance data. Epidemiology. 2015;26(5):653-60.  https://doi.org/10.1097/EDE.0000000000000324  PMID: 26214334 
  16. Rosinska M, Pantazis N, Janiec J, Pharris A, Amato-Gauci AJ, Quinten C, et al. Potential adjustment methodology for missing data and reporting delay in the HIV Surveillance System, European Union/European Economic Area, 2015. Euro Surveill. 2018;23(23):1700359.  https://doi.org/10.2807/1560-7917.ES.2018.23.23.1700359  PMID: 29897039 
  17. Andersson E, Nakagawa F, van Sighem A, Axelsson M, Phillips AN, Sönnerborg A, et al. Challenges in modelling the proportion of undiagnosed HIV infections in Sweden. Euro Surveill. 2019;24(14):1800203.  https://doi.org/10.2807/1560-7917.ES.2019.24.14.1800203  PMID: 30968824 
  18. Van Buuren S, Groothuis-Oudshoorn K. mice: Multivariate imputation by chained equations in R. J Stat Softw. 2011;45(3):1-67.  https://doi.org/10.18637/jss.v045.i03 
  19. R Core Team. R: A language and environment for statistical computing. Vienna: R Foundation for Statistical Computing; 2023. Available from: https://www.r-project.org
  20. McAuley A, Palmateer NE, Goldberg DJ, Trayner KMA, Shepherd SJ, Gunson RN, et al. Re-emergence of HIV related to injecting drug use despite a comprehensive harm reduction environment: a cross-sectional analysis. Lancet HIV. 2019;6(5):e315-24.  https://doi.org/10.1016/S2352-3018(19)30036-0  PMID: 30981674 
  21. Mahy MI, Sabin KM, Feizzadeh A, Wanyeki I. Progress towards 2020 global HIV impact and treatment targets. J Int AIDS Soc. 2021;24(Suppl 5) Suppl 5;e25779.  https://doi.org/10.1002/jia2.25779  PMID: 34546655 
  22. Joint United Nations Programme on HIV/AIDS (UNAIDS). AIDS, crisis and the power to transform: UNAIDS Global AIDS Update 2025. Geneva: UNAIDS; 2025. Licence: CC BY-NC-SA 3.0 IGO. Available from: https://www.unaids.org/sites/default/files/2025-07/2025-global-aids-update-JC3153_en.pdf
  23. Palella FJ Jr, Baker RK, Moorman AC, Chmiel JS, Wood KC, Brooks JT, et al. Mortality in the highly active antiretroviral therapy era: changing causes of death and disease in the HIV outpatient study. J Acquir Immune Defic Syndr. 2006;43(1):27-34.  https://doi.org/10.1097/01.qai.0000233310.90484.16  PMID: 16878047 
  24. Crum NF, Riffenburgh RH, Wegner S, Agan BK, Tasker SA, Spooner KM, et al. Comparisons of causes of death and mortality rates among HIV-infected persons: analysis of the pre-, early, and late HAART (highly active antiretroviral therapy) eras. J Acquir Immune Defic Syndr. 2006;41(2):194-200.  https://doi.org/10.1097/01.qai.0000179459.31562.16  PMID: 16394852 
  25. Smit C, Geskus R, Walker S, Sabin C, Coutinho R, Porter K, et al. Effective therapy has altered the spectrum of cause-specific mortality following HIV seroconversion. AIDS. 2006;20(5):741-9.  https://doi.org/10.1097/01.aids.0000216375.99560.a2  PMID: 16514305 
  26. Churchill D, Waters L, Ahmed N, Angus B, Boffito M, Bower M, et al. British HIV Association guidelines for the treatment of HIV-1-positive adults with antiretroviral therapy 2015. HIV Med. 2016;17(S4) Suppl 4;s2-104.  https://doi.org/10.1111/hiv.12426  PMID: 27568911 
  27. World Health Organisation (WHO). Guideline on when to start antiretroviral therapy and on pre-exposure prophylaxis for HIV. Geneva: WHO; 2015. Available from: https://www.who.int/publications/i/item/9789241509565
  28. Cohen MS, Chen YQ, McCauley M, Gamble T, Hosseinipour MC, Kumarasamy N, et al. Prevention of HIV-1 infection with early antiretroviral therapy. N Engl J Med. 2011;365(6):493-505.  https://doi.org/10.1056/NEJMoa1105243  PMID: 21767103 
  29. Lundgren JD, Babiker AG, Gordin F, Emery S, Grund B, Sharma S, et al. Initiation of antiretroviral therapy in early asymptomatic HIV infection. N Engl J Med. 2015;373(9):795-807.  https://doi.org/10.1056/NEJMoa1506816  PMID: 26192873 
  30. Nandwani R. Pre-exposure prophylaxis is approved in Scotland. Lancet HIV. 2017;4(6):e238-9.  https://doi.org/10.1016/S2352-3018(17)30078-4  PMID: 28416197 
  31. Hanum N, Cambiano V, Sewell J, Rodger AJ, Nwokolo N, Asboe D, et al. Trends in HIV incidence between 2013-2019 and association of baseline factors with subsequent incident HIV among gay, bisexual, and other men who have sex with men attending sexual health clinics in England: A prospective cohort study. PLoS Med. 2021;18(6):e1003677.  https://doi.org/10.1371/journal.pmed.1003677  PMID: 34143781 
  32. Cambiano V, Miners A, Lampe FC, McCormack S, Gill ON, Hart G, et al. The effect of combination prevention strategies on HIV incidence among gay and bisexual men who have sex with men in the UK: a model-based analysis. Lancet HIV. 2023;10(11):e713-22.  https://doi.org/10.1016/S2352-3018(23)00204-7  PMID: 37923485 
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