Women make up more than half of all people living with HIV – why are they under represented in studies of new medicines?

Today, out of all the key populations affected by the HIV epidemic, girls and women make up more than half (54%) of all people living with HIV worldwide and HIV/AIDS is the third leading cause of death globally for women aged 15–49.1,2

Gender inequalities and limited access to health services play an important role in contributing to these outcomes. Globally, only 55% of women and adolescent girls report being in control of decisions about their own sexual and reproductive health and rights.2 As a consequence, adolescent girls and young women (aged 15¬–24) accounted for 20% of new HIV infections in 2020 compared with 12% for similarly aged males.3 These impacts are most pronounced in sub-Saharan Africa, where adolescent girls and young women accounted for one in four HIV infections in 2020, despite representing just 10% of the population.3,4

Annemiek de Ruiter, Head of Global Medical Sciences, ViiV Healthcare, specialises in the study of HIV in women:

Annemiek de Ruiter, Head of Global Medical Sciences explains why we need to increase gender diversity in our clinical trials.

Although HIV in women is a serious and significant issue, women remain largely under-represented in HIV clinical trials. A large proportion of HIV clinical trials and cure-related research takes place in resource sufficient countries, where the HIV epidemic is predominantly in men who have sex with men.5

The under-representation of women in HIV clinical trials leads to gaps in scientific knowledge about how HIV in women may behave differently compared to men. These variations could potentially affect the safety and efficacy of treatment, as well as how medicines interact with the female body.6

These research gaps limit our understanding of the effects of HIV treatment in women, and our ability to address differences between men and women in HIV treatment and prevention outcomes.

Current guidelines for treatment using antiretrovirals (ARVs) do not distinguish between men and women, with the exception of women who are pregnant or planning a pregnancy, for whom there are even fewer data available.

"Every four minutes, three young women become infected with HIV"7

How can we understand more about HIV in women?

The lack of enrolment of women in HIV clinical trials prevents study findings from being truly relevant to women. If gender-specific biological markers do not exist and relevant questions are not asked (or are unable to be answered because of inadequate numbers of female study participants), how can we have confidence in the treatments we give to women living with HIV?

Competing priorities for women, which can include childcare, home responsibilities and shift-driven jobs, often cause challenges for traditional recruitment into HIV clinical trials and may contribute to a gender imbalance in studies.5

In addition, too often, budgetary and time constraints limit the ability of study sites to develop women-friendly recruitment strategies and therefore limit their ability to engage with women.8

How do we close the research gap for HIV in women?

Targeted enrolment of women in clinical trials and careful, separate analysis of data for men and women are crucial to gaining further insights into biological differences between sexes in HIV infection, to designing sex-specific approaches to HIV treatment, and in the future, to potential elimination of the virus through cure or remission.

Increasing female recruitment into HIV studies requires commitment from basic, clinical and social scientists, as well as creating an understanding in women themselves of the objectives and importance of clinical research. Without this, the end of the HIV epidemic will remain out of reach.

Annemiek de Ruiter, Head of Global Medical Sciences, ViiV Healthcare says there’s no simple solution to correcting these issues related to HIV in women:

Annemiek de Ruiter, Head of Global Medical Sciences, explains the barriers to including women in clinical trials.

Our commitment to closing the research gap for HIV in women

Recognising the impact of the HIV epidemic on girls and women, at ViiV Healthcare, we are putting specific emphasis on this population as part of our HIV clinical trials strategy and community partnership programmes.

We contribute knowledge to fill gaps and address unmet medical needs through our research programmes to understand more about HIV in women. We have, and will continue to undertake and support numerous HIV clinical trials, with more than 6,000 women (including 571 transgender women) taking part in our treatment and prevention clinical trials.926

While women represent 19%, on average, of participants in studies of ARVs, several clinical trials sponsored by ViiV Healthcare have surpassed this mark, including one study with 100% participation by women (ARIA).5

Furthermore, through the international Positive Perspectives survey of people living with HIV, we continue to explore the unique challenges faced by women living with HIV. This research aims to expand community-wide knowledge on gender discrepancies regarding attitudes towards health, sexual intimacy and relationships with healthcare providers.

  1. UNAIDS. 20.2 million girls and women living with HIV. Available at: Last accessed June 2022
  2. UNAIDS. Executive Director's message on International Women’s Day 2022. Available at: Last accessed June 2022
  3. UNAIDS. UNAIDS data 2020. Available at: Last accessed June 2022
  4. UNAIDS. Women and girls carry the heaviest HIV burden in sub-Saharan Africa. Available at: Last accessed June 2022
  5. Curno J, et al. J Acquir Immune Defic Syndr 2016;71:181–8
  6. British HIV Association. British HIV Association guidelines for the treatment of HIV-1-positive adults with antiretroviral therapy 2015 (2016 interim update). Available at: Last accessed June 2022
  7. UNAIDS. Women and Girls and HIV. Available at: Last accessed June 2022
  8. Gianella S, et al. J Int AIDS Soc 2016;19:20706
  9. Cahn P, et al. Lancet 2013;382:700–8
  10. Raffi F, et al. Lancet 2013;381:735–43
  11. Clotet B, et al. Lancet 2014;383:2222–31
  12. Walmsley S, et al. N Engl J Med 2013;369:1807–18 (and suppl. appendix)
  13. Castagna A, et al. J Infect Dis 2014;210:354–62
  14. Orrell C, et al. Lancet HIV 2017;4:e536–46
  15. Aboud M, et al. Lancet Infect Dis 2019;19:253–64
  16. Trottier B, et al. Antiviral Therapy 2017;22:295–305
  17. Dooley K, et al. Clin Infect Dis 2020;70:549–56
  18. Llibre J, et al. Lancet 2018;391:839–49
  19. Cahn P, et al. Lancet 2019;393:143–55
  20. van Wyk J, et al. Clin Infect Dis 2020;71:1920–9
  21. Rolle CP, et al. IAS 2021. Poster PEB182
  22. Llibre JM, et al. Clin Infect Dis 2022;ciac130 [published online ahead of print]
  23. Swindells S, et al. N Engl J Med 2020;382:1112‒23
  24. Orkin C, et al. N Engl J Med 2020;382:1124–35
  25. Landovitz RJ, et al. N Engl J Med 2021;385:595–60
  26. Delany-Moretlwe S, et al. Lancet 2022;399:1779–89

NP-GBL-HVX-COCO-220073 July 2022

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