In global health, true breakthroughs are rare. When they come, their value is measured not in laboratories, but in the lives they save.

Today, that test centres on lenacapavir – sometimes called Len – a long-acting HIV prevention drug that could transform the global epidemic, particularly for adolescent girls and young women, who remain at its heart.

Across sub-Saharan Africa, adolescent girls and young women continue to face a disproportionate risk of HIV infection. Gender inequality, stigma, and the lack of control over their own health choices mean that many existing prevention tools do not reach them effectively. Daily oral Pre-Exposure Prophylaxis (PrEP), a similar HIV prevention drug, has delivered strong results in some key populations. But for many women and girls, adherence can be hard because of scrutiny at home, fear of stigma, and the reality of changing routines, school, travel, and other competing demands.

Len changes that equation.

A simple injection twice a year offers near-complete protection against HIV infection, without the burden of daily pills or drawing unwanted attention. For many women and girls, it could be the first HIV prevention tool they can use discreetly, on their own terms. Len is both a scientific advance and a shift in power.

But this breakthrough will only matter if it reaches those who need it most – and that depends on how it is produced, priced, and delivered.

Unitaid – which invests in better ways to prevent, diagnose and treat diseases – and partners have secured a ceiling price of around £30 per person per year for quality-assured generic Len, removing one of the biggest barriers to access. But the agreements go beyond pricing, to reshape where the drug is produced.

By supporting the development of locally produced generics, Unitaid is helping to reduce dependency on limited global supply, shorten delivery timelines, and build sustainable manufacturing capacity in regions hardest hit by HIV.

Meanwhile, both Unitaid and the Elton John AIDS Foundation are working closely to reach the communities that traditional health systems continue to miss. Whether it’s through community-based and online pharmacies, mobile clinics, or peer-led organisations, we must reach the unreached if epidemic control is to become a reality.

For adolescent girls and young women living in countries with high HIV rates, this matters. Local production, reliable supply chains, and distribution networks rooted in their daily lives, mean Len that is consistently available, closer to where they live, and better integrated into the services they already trust.

Scaling up Len at an estimated £30 per person, per year, would cost roughly £300 million annually for 10 million people; a modest investment compared with the long-term cost of HIV treatment, and a fraction of broader global health spending.

The UK government’s approach to global health is characterised by a growing recognition that progress depends on partnership, investment, and locally led solutions, rather than an outdated donor-recipient paradigm. This approach is essential for ensuring that innovations like Len are not only developed, but manufactured and distributed at scale in the regions that need them most.

At its heart, the Len rollout is about health sovereignty: the ability of countries to protect their own populations without being left vulnerable when donor priorities shift, as we have seen with growing alarm in recent years. If we fail to invest in HIV prevention now, we risk a resurgence that will quickly consume far more of stretched health budgets.

Each week, 4,000 adolescent girls and young women acquire HIV globally, including 3,300 in sub-Saharan Africa. In west and central Africa, this group is three times more likely to acquire HIV than their male counterparts. These figures demonstrate how deeply gender inequality shapes who gets protected and who does not. HIV prevention is as much about personal autonomy as national sovereignty.

If we seize this moment, the next generation could grow up with real control over HIV risk. If we hesitate, one of the most promising advances in decades will falter and we will all have to deal with the consequences.

We only get one chance to do this right.

Philippe Duneton is the executive director of Unitaid

Anne Aslett is CEO of the Elton John AIDS Foundation

This article has been produced as part of The Independent’s Rethinking Global Aid project