Zambia’s first results on long-acting injectable PrEP offered outside clinical trials

What is this story about? 

In February 2024, Zambia became the first country in sub-Saharan Africa to introduce long-acting injectable PrEP (pre-exposure prophylaxis), known as cabotegravir (CAB-LA), outside of a study setting. This injectable provides approximately two months of HIV protection, significantly reducing the risk of infection by preventing the virus from replicating.

Studies have demonstrated that injectable PrEP is more effective than daily oral PrEP, as it’s harder to miss doses. Research in gay and bisexual men and transgender women found that injectable PrEP reduced the risk of HIV by 66% compared to oral PrEP. Among cisgender women, the risk was reduced by 88%.

Rollout of injectable PrEP in Zambia 

The rollout began after training supervisors, healthcare workers, and community-based volunteers and preparing health facilities. CAB-LA was provided to eligible individuals, according to the national implementation plan, across six health facilities in two districts. By April, 609 individuals, with a median age of 24, were enrolled. Among them, 56% were women, 7% identified as key populations, and 40% were categorised as high-risk populations. Most (70%) had never used PrEP before, while 30% transitioned from oral PrEP.

What did they find out?

Of the 609 participants, 406 were due for their second injection by April. Of these, 91% (371) received it on schedule, while 9% were pending reviews.

A total of 24 participants (about 4%) discontinued CAB-LA. Hepatitis B accounted for most of the discontinuations (20 cases), while two participants stopped due to pregnancy, one due to a severe rash, and one because of severe pain at the injection site. Most of those who discontinued were switched to oral PrEP.

Speaking to journalists during a press briefing, Professor Lloyd Mulenga from the Ministry of Health in Zambia stated that the number of those enrolled who acquired HIV had now increased from two to four, clarifying that these individuals likely had undetected HIV at the time they started PrEP.

“This isn’t a failure of cabotegravir,” he said, explaining that the HIV antibody tests were not sensitive enough. The Ministry now plans to revise testing guidelines to avoid similar issues in the future.

Dr Mulenga also expressed surprise at the high rate of hepatitis B among participants, but explained that many of those enrolled were from key populations, such as female sex workers and men who have sex with men, who are at higher risk for both HIV and sexually transmitted infections. He emphasized that having hepatitis B should not prevent access to CAB-LA, and new guidelines are also being developed to address this.

Looking ahead 

The global supply of CAB-LA has been limited since its first approval by the U.S. FDA in December 2021. However, at the HIVR4P conference on October 7, ViiV Healthcare, the manufacturer of CAB-LA, announced a commitment to make at least two million doses available for low- and middle-income countries during 2025-2026. This supply will be triple what was available in 2024, aiming to meet the increasing demand in regions with the highest HIV burden.

By Edith Magak