Taking a pill every single day is harder than it sounds. Miss a few, and HIV can rebound and start building resistance. For decades that daily discipline has been the price of keeping the virus quiet. A trial run across Uganda, Kenya and South Africa now shows that for many people, the pills can be traded for a pair of injections given once every eight weeks, with no loss of control.
The study, called CARES, was published in Nature Medicine by Cissy Kityo of the Joint Clinical Research Centre in Kampala and colleagues. It enrolled 512 African adults living with HIV-1 who were already doing well on standard oral therapy. Everyone had a screening viral load below 50 copies per milliliter, the threshold clinicians use to call the virus suppressed, and none had a history of treatment failure. Half were randomly assigned to keep taking their daily tablets. The other half switched to intramuscular shots of two long-acting drugs, cabotegravir and rilpivirine, delivered every eight weeks.
What the numbers showed at 96 weeks
The researchers checked viral load every 24 weeks and followed participants out to 96 weeks. By that point, 247 of 255 people in the injection group, or 97 percent, still had a viral load under 50 copies per milliliter. In the pill group the figure was 250 of 257, also 97 percent. The difference between the two arms was 0.4 percentage points, with a confidence interval running from -3.1 to 2.0. That sits comfortably inside the 10 percent margin the trial set in advance to declare the injections no worse than the pills.
The word to notice there is noninferiority. The shots were not designed to beat daily therapy. They were designed to match it while removing the burden of remembering a pill every morning. On that measure they succeeded, and they held up across nearly two years of dosing rather than a brief window.
Why an African trial matters here
Long-acting cabotegravir and rilpivirine had already been tested, but mostly in higher-income settings. Sub-Saharan Africa carries the largest share of the global HIV epidemic, and drug regimens, clinic access and background health conditions there do not always mirror the populations in earlier studies. Showing that the injectable approach delivers durable suppression in Ugandan, Kenyan and South African patients closes a gap that has real consequences for how treatment programs are built.
An every-eight-week schedule also reshapes what a clinic visit looks like. Instead of monthly pharmacy pickups and the private logistics of storing pills at home, a person comes in six or seven times a year for an injection. For anyone who worries about stigma or struggles with daily adherence, that shift is not trivial.
The safety picture and its limits
The injections were not free of downsides. Serious adverse events, graded 3 or higher, showed up in 41 of 255 people in the injection group, about 16 percent, compared with 22 of 257, or 9 percent, among those on pills. Most of these were judged unrelated to the study drugs. One participant stopped the injections because of an injection-site abscess, the only treatment-related event that led to discontinuation. Sore, reactive injection sites are a known feature of this kind of therapy, and the trial reflects that.
Some caveats are worth keeping in view. The trial was open-label, meaning participants and staff knew which treatment each person was getting. It also enrolled only people who were already suppressed and stable, so the findings say nothing about starting injectable therapy in someone whose virus is not yet under control, or in patients with prior treatment failure. And an eight-week clinic rhythm still depends on a health system that can reliably deliver injections on schedule, which is its own challenge in many settings.
Even with those boundaries, the message is straightforward. In the populations that carry much of the world's HIV burden, a treatment that asks for a visit every couple of months worked as well as one that asks for a pill every day. The authors write that long-acting therapy may now be considered for use in African treatment programs.
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