For many years, scientists have tried to answer several questions about whether various hormonal contraceptive methods (i.e., pills, injectables, implants, hormone-releasing IUDs, patches, and vaginal rings) impact various HIV-related risks. Key questions on this subject include:
The first question is the most controversial, and is a critically important question for women's health - particularly for those living in high HIV prevalence countries, including many in Eastern and Southern Africa. However, for a number of methodological reasons (many of which are detailed in this paper), it is extremely complex to design studies that will provide definitive answers.
- Are HIV-negative women who use specific methods of hormonal contraception more likely to acquire HIV?
- Are women living with HIV who use specific methods of hormonal contraception more likely to transmit their infection to a male sexual partner?
- Are women living with HIV and using specific methods of hormonal contraception likely to experience faster clinical disease progression?
- If a woman living with HIV is using antiretroviral therapy (i.e., medications to treat HIV), will using any specific method of hormonal contraception result in drug interactions. In other words, could using both medications at the same time make either medication less effective, or more likely to result in side effects?
The first question is the most controversial, and is a critically important question for women's health - particularly for those living in high HIV prevalence countries, including many in Eastern and Southern Africa. However, for a number of methodological reasons (many of which are detailed in this paper), it is extremely complex to design studies that will provide definitive answers.
At the request of the World Health Organization, I've had the opportunity to lead incredible teams of researchers to conduct systematic reviews of the evidence on this issue (as well as on some of the other questions noted above). Systematic reviews collect, evaluate, and summarize all available studies on a given question to try to clarify what the best available evidence tells us. Our first systematic review on this topic was completed in 2012 and published in 2013 in Lancet Infectious Diseases. The evidence base continued to grow, and we were asked to conduct an updated review on this topic in 2014, which we published in the journal Contraception.
In the last two years, the evidence based has continued to grow rapidly, and the quality of studies has continued to improve over time. We were recently asked by WHO to conduct a third systematic review on this issue, which we recently published in the journal AIDS. This updated review includes all scientific studies on this topic published through January 15, 2016 (and at the time of writing this blog in October 2016, I am not aware of any new relevant studies published since January 15, 2016).
The full text of the systematic review is available here (click where it says "Article as PDF" under the "Article Tools" bar on the right), and a press release is available here. In brief, we concluded that existing evidence suggests a reassuring lack of increased risk of HIV acquisition for users of oral contraceptive pills, the NET-EN injectable contraceptive (which is used mostly in South Africa), and contraceptive implants. However, new data on intramuscular depot medroxyprogesterone acetate (DMPA), an injectable contraceptive most commonly sold as Depo Provera, heightens existing concerns about a possible increase in risk of HIV acquisition in women who use the method.
WHO monitors this evidence on an ongoing basis, in efforts to keep guidelines like the Medical Eligibility Criteria for Contraceptive Use aligned with scientific data on a continuous basis. In response to our review, WHO issued a statement, and noted that:
In the last two years, the evidence based has continued to grow rapidly, and the quality of studies has continued to improve over time. We were recently asked by WHO to conduct a third systematic review on this issue, which we recently published in the journal AIDS. This updated review includes all scientific studies on this topic published through January 15, 2016 (and at the time of writing this blog in October 2016, I am not aware of any new relevant studies published since January 15, 2016).
The full text of the systematic review is available here (click where it says "Article as PDF" under the "Article Tools" bar on the right), and a press release is available here. In brief, we concluded that existing evidence suggests a reassuring lack of increased risk of HIV acquisition for users of oral contraceptive pills, the NET-EN injectable contraceptive (which is used mostly in South Africa), and contraceptive implants. However, new data on intramuscular depot medroxyprogesterone acetate (DMPA), an injectable contraceptive most commonly sold as Depo Provera, heightens existing concerns about a possible increase in risk of HIV acquisition in women who use the method.
WHO monitors this evidence on an ongoing basis, in efforts to keep guidelines like the Medical Eligibility Criteria for Contraceptive Use aligned with scientific data on a continuous basis. In response to our review, WHO issued a statement, and noted that:
The World Health Organization will convene an expert review group later in 2016 to examine the links between the use of various hormonal contraceptive methods and women’s risk of HIV acquisition. The expert review group will assess whether current WHO guidance needs to change in the light of a new review of data, published in AIDS on 9 August 2016, which was commissioned by WHO.
People interested in this topic should stay tuned for the results of the WHO meeting. For those interested in some of the other key questions noted above, here are some additional resources:
- Are women living with HIV who use specific methods of hormonal contraception more likely to transmit their infection to a male sexual partner? Main (2013) systematic review here, with an update here.
- Are women living with HIV and using specific methods of hormonal contraception more likely to experience faster clinical disease progression? Main (2013) systematic review here, with an update here.
- Are drug-drug interactions expected between specific hormonal contraceptive methods and specific antiretroviral medications? Review here, updated review forthcoming.
- Modeling studies to understand the impact of various policy responses to the HC-HIV acquisition issue in various epidemiological contexts: here and here.
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