Previous research has suggested that women who use the three monthly injectable contraceptive Depo-Provera could be at a 20 to 60% increased risk of contracting HIV. (Reuters)

HIV and 'the shot': Could a leading contraceptive fuel HIV infection risk?

Sinaye Ngcapu
New evidence has spurred a large, multi-country study and an international meeting on the matter but will answer come soon enough for women?

COMMENT

Science may be closer than ever before to ending a 25-year long debate about hormonal contraception and HIV infection risk but as the world deliberates, women may face tough choices.

South Africa offers women many free contraceptives in the form of pills, injections or implants. Some of these birth control methods are hormonal, meaning that they pre- vent unwanted pregnancies by using female hormones to prevent women’s ovaries from releasing eggs every month.

Access to safe, convenient, inexpensive, effective and reversible methods of hormonal contraception is essential to reducing unwanted pregnancies, maternal and child deaths and the mother-to-child transmission of HIV.

In South Africa, an estimated 60% of women in their reproductive years use contraceptives, according to the latest 2003 Demographic and Health Survey. Most opt for the three-monthly, long-acting injectable contraceptive depot medroxyprogesterone acetate, more commonly known by the brand name  Depo-Provera. The injection is often referred to as “the shot”. Some women under the age of 25 and who have not had children may use  NET-EN, a two-monthly injectable progestin contraceptive.

Many of these women are also at a high risk for HIV infection. In South Africa and sub-Saharan Africa, adolescent and young women account for about 25% of new HIV infections, according to  UNAids’ 2016 Prevention Gap Report. Growing evidence sug- gests that pregnancy and the period shortly after birth may be especially risky times for women to be infected with HIV, according to  2011 research published in the Journal of AIDS.

For 25 years, the scientific community has debated whether hormonal contraceptives could affect women’s risk of HIV infection, particularly high-dose injectable progestins such as Depo-Provera and NET-EN. A  review published in August in the same journal evaluated findings from several quality studies conducted among women in countries including Zimbabwe, Kenya and South Africa. Data from these studies suggests Depo-Provera users are at a 20% to 60% increased risk of contracting HIV compared to women not using hormonal contraception.

Importantly, this research did not find similar evidence that NET-EN, oral daily contraception or implants increased women’s risk of HIV infection.

But studies included in the review were not designed to evaluate this risk. They were also not set up to provide conclusive evidence about whether other behaviours among contraceptive users, such as possible reduced condom use, helped to fuel the increased HIV infection rates found among Depo-Provera users in the review.

Meanwhile, data published in 2005 by the Guttmacher Institute suggests that users of hormonal contraception, especially those on Depo-Provera, may not always opt for condoms. Researchers say this is because women’s need to prevent unwanted pregnancies may be higher than their perceived risk of HIV infection. Inconsistent condom use could partly explain the greater risk of HIV infection found in the review.

So, does hormonal contraception play a role in HIV acquisition? 

To provide a more definitive answer, a large clinical trial called  Echo is underway in several African countries. As part of the study, women aged between 16 and 35 will receive Depo-Provera, hormonal implants or a small nonhormonal copper implant inserted into the uterus to prevent pregnancy.

Echo’s design has raised scientific and ethical difficulties in assigning female participants a contraceptive choice. But the study is also likely to provide the best answer to whether hormonal contraceptives put women at an increased risk of HIV infection. The study, set to be released in 2018, could also inform evidence-based contraception and HIV-reduction policies in sub-Saharan Africa.

Meanwhile, the  Centre for the Aids Programme of Research in South Africa recently completed a study that may reveal why Depo-Provera could be increasing HIV infections.

Presented at the recent  International Aids Conference, the study found that use of the injection was associated with poorer immune responses, at a cellular level, to infections in women’s vaginas. These responses may be crucial to protecting against HIV infection. Depo-Provera use was also associated with the increased presence of CD4 cells in women’s vaginas. These cells are easily infected by HIV.

The centre’s findings suggest that using the common hormonal contraceptive may change the ecosystem of a woman’s reproductive tract and make her more susceptible to HIV infection.

In light of new evidence, the World Health Organisation (WHO) will convene experts later this year to examine whether the global body needs to rethink its guidance on hormonal contraception and HIV infection risk. Until now, the lack of conclusive evidence has led the WHO to recommend that women using the injection should also use condoms to prevent HIV infection.

The imperative to find safe and effective fertility controls for Africa’s women that do not put them at a further risk of HIV infection cannot be sufficiently underscored.

As we await the Echo trial results, millions of young women, particularly in sub-Saharan Africa, may have to continue to choose between reliable birth control and the possibility of increased HIV infection risk.

Sinaye Ngcapu is a research associate and a basic scientist at the Centre for the Aids Programme of Research in South Africa. He recently recieved the Aids 2016 Women, Girls and HIV Investigator award at the International Aids Conference in Durban for his work on hormonal contraception.

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