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The SCHIELD Implant: Preventing Unintended Pregnancy and HIV with One Product

A collaborative effort to create a new reproductive health implant based on women’s needs and innovative medical technologies


Reproductive health concerns have profound effects on both individual lives and societies. Globally, 89 million unintended pregnancies, nearly 870,000 new HIV infections, and millions more other sexually transmitted infections occur among women each year.

In the global fight against the HIV pandemic, a major focus has been the development of medications that prevent HIV infections in people who are at ongoing risk, known as pre-exposure prophylaxis (PrEP). A key milestone was the 2012 introduction of oral PrEP: a daily pill that, if taken correctly and consistently, prevents HIV transmission.

Advances in HIV prevention

Additional breakthroughs occurred in 2021, when the FDA approved the first long-acting injectable PrEP medication and the World Health Organization (WHO) conditionally recommended the dapivirine vaginal ring, which has since been approved by Kenya, South Africa, Uganda, and Zimbabwe. 

Despite the availability of oral PrEP and the promise of these two additional HIV prevention options, gaps remain in the accessibility, affordability, and acceptability – with implications for sustained uptake and use by women. 

As research in HIV prevention as well as the contraceptive field has shown, there is no single product that will work for all individuals and women have different characteristics that they prefer. Some women want a long-acting method, others want one that’s quickly reversible, and still others value discretion above all other qualities. The users’ priorities are as diverse as their circumstances.

RTI's involvement in HIV prevention

RTI’s work in global health and gender equity has led us to work on many HIV prevention projects, especially in sub-Saharan Africa, where the risk of HIV infection is greatest. In 2013, with funding from USAID, and later in 2016, with additional funds from the Bill and Melinda Gates Foundation, we began working on an implantable long-acting HIV prevention device. Known as TIP, this ongoing program merges our experience in HIV prevention with our decades of work in medical device innovation.

Key features of the SCHIELD implant

The USAID-funded SCHIELD project has successfully expanded the achievements of TIP. Launched in 2017, SCHIELD aimed to create a multipurpose prevention technology implantable product that provides both contraception and HIV prevention. Our multipurpose prevention technology implant underwent preclinical trials and offers a combination of attributes that surpass existing drug delivery systems: 

  • Is biodegradable, eliminating the necessity for follow-up visits to a health care clinic
  • Can be removed by a health care provider in the event of adverse reactions or desire for return to fertility
  • Provides long-term, discreet protection

Our SCHIELD team made critical advancements in optimizing the drug formulations and device configuration. Tenofovir alafenamide (TAF) is one of the two FDA approved HIV antiretroviral (ARV) drugs that is used for daily oral PrEP. This made it a natural choice for our team and others working both with the Bill and Melinda Gates Foundation and independently to use in implants for long-acting HIV prevention. However, when these various TAF implants were tested in vivo, all were found to cause local reactions at the implant sites. 

Our team pivoted to using another ARV called islatravir (ISL), which is undergoing clinical trials for oral PrEP. Our preclinical in vivo studies have recently shown that not only does our biodegradable ISL implant not cause adverse reactions, but also that it successfully protects against viruses similar to HIV and maintains a consistent drug delivery of six months. 

Future goals for HIV prevention

These breakthroughs mark major milestones in the development of long-acting HIV prevention, providing women with more options that come with fewer burdens. Future goals are to combine ISL and a contraceptive into a single implant and to extend the drug delivery duration.

To optimize future uptake of this technology by women and health care providers globally, we have also incorporated end-user feedback into the early stage of product development. Working with partners in South Africa and Zimbabwe, we have conducted interviews and focus groups of health care providers and potential end users, exploring their preferences for the implants along with potential future marketing strategies.

The way I see it, SCHIELD implant is the best compared to other implants available. Actually, it's excellent because it's 2-in-1 and it does not have to be removed. This means less pain.

End users in these focus groups who had given birth before preferred the longest possible duration offered, which was 3 years. However, we learned that women who have never had children tended to prefer a device that would be effective for 1 to 2 years. Because they also face a higher risk of HIV infection, they may be the ideal audience for our implant.

Future avenues of research include whether similar implants could be used to treat cancer, other infectious diseases, and opioid use disorder. Our hope is that the implants we develop will impact end-users by providing a new option for contraception and HIV prevention, seamlessly integrated into women’s lives, making it easier for them to plan pregnancies and protect themselves from HIV, even in high-risk circumstances.