June 27, 2024

Women and girls in Sub-Saharan Africa account for the largest share of HIV cases globally, which makes prevention of new cases among this population a critical part of achieving the UNAIDS goal of ending the threat of HIV by 2030.

Understanding a person’s risk of acquiring HIV can be challenging because it often involves asking individuals questions that may be personal, time-consuming or stigmatizing to answer. That’s why a team of researchers, led by public health experts at the UNC Gillings School of Global Public Health, have developed a new tool that moves this assessment to the policy level.

The tool used population-level data from 15 countries in Southern, Eastern and West/Central Africa and examined factors that predict which women between the ages of 15-49 years are most at risk for acquiring HIV. The research team’s findings reveal that living in an area where a high proportion of the population has unsuppressed HIV is the strongest predictor of new infections. They also found that whether a woman reports a sexual partner living outside the home is an important predictor.

Photo: Dr. Rosenberg

Dr. Nora Rosenberg

“Risk assessment tools have been developed for African women previously, but ours is the most representative. It’s applicable to over 100 million women across 15 African countries,” said Nora Rosenberg, PhD, associate professor of health behavior at the Gillings School and the study’s principal investigator. “By looking at a dataset with such a broad geographic range, we were able to examine epidemiologic factors, whereas earlier work focused on individual factors.”

Researchers developing the tool were able to estimate that by offering a small fraction of the population a prevention medication called pre-exposure prophylaxis (PrEP), which is highly effective at preventing HIV, a substantial share of the 402,000 annual new cases among women in these countries could be prevented.

Their study, published recently in Clinical Infectious Diseases, outlines the development of the risk assessment tool and the tradeoffs between sensitivity (the proportion of cases averted) and the scale of prevention efforts.

Dr. Bonnie Shook-Sa

Dr. Bonnie Shook-Sa

“We present a range of options for policy-makers to weigh,” said Bonnie Shook-Sa, DrPH, associate professor of biostatistics and co-investigator on the study. “We present a few scenarios, exploring how many people would need to adhere to PrEP to avert 5%, 33%, 67% and 95% of new infections.”

In the study, the team found that two-thirds of new HIV cases (260,000) could be averted if 25.1 million women were adherent to PrEP. Alternatively, one-third of new HIV cases (130,000) could be averted with only 7.9 million women perfectly adherent to PrEP. This is a crucial balance that public health officials must seek when considering their prevention goals and the resources available.

Researchers in the study mention that perfect adherence to PrEP has, in practice, been a challenge for users, and so one of the next steps for the research team is to conduct future studies with the tool that explore estimates based on a range of assumptions about real-world implementation and effectiveness.

Read the full study online.

Authors in the study include: Nora E Rosenberg, PhD, Bonnie E Shook-Sa, DrPH, Amber M Young, BS, Yating Zou, BS, Lynda Stranix-Chibanda, MMed, Marcel Yotebieng, PhD, Nadia A Sam-Agudu, MD, Sam J Phiri, PhD, Professor, Wilbroad Mutale, Professor, Linda-Gail Bekker, PhD,  Manhattan E Charurat, PhD, Sizulu Moyo, PhD, Khangelani Zuma, Jessica Justman, MD, Michael G Hudgens, PhD, and Benjamin H Chi, MD.

Contact the UNC Gillings School of Global Public Health communications team at sphcomm@unc.edu.

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