TasP First, PrEP Alongside:
Restoring Balance to the HIV Response

By Dr. José M. Zuniga

There is a phrase in the HIV field that has always bothered me: “We cannot treat our way out of the epidemic.” It is repeated so often that it has acquired the status of received wisdom. And, like many slogans, it contains enough truth to make challenging it seem almost heretical. So, allow me some heresy.

When I started in this movement, I developed a reputation as an enfant terrible. Age has apparently not cured the condition. Occasionally, that has been to my detriment, especially when addressing commercial determinants of health. But I remain stubbornly committed to a principle that should not be controversial in public health: data and evidence should prevail, even when they complicate the prevailing narrative. And the evidence tells us that the pendulum may be swinging too far.

For much of the past decade, our HIV strategy rested on a powerful combination: antiretroviral therapy (ART) for people living with HIV, including treatment as prevention (TasP), complemented by pre-exposure prophylaxis (PrEP) and other prevention interventions for people who are HIV-negative. TasP fundamentally altered our understanding of the epidemic because viral suppression accomplishes two extraordinary things simultaneously: it preserves the health and lives of people living with HIV and eliminates the risk of sexual HIV transmission – undetectable = untransmittable, or U=U.

The astonishing public health return on investment that TasP represents should be crystal clear. And it was not an idea conjured from advocacy rhetoric. The scientific trail stretches back nearly two decades:

  • In 2006, Dr. Julio Montaner et al advanced what was then a provocative proposition: expanding access to ART could do more than save the lives of people living with HIV – it could help curb HIV transmission at the population level. The logic was elegantly straightforward. ART suppresses viral replication; lower viral load dramatically reduces infectiousness; therefore, sufficiently broad and sustained treatment coverage could affect the trajectory of the epidemic. What became known as TasP began moving from clinical observation toward population-health strategy.
  • Then came the Swiss Statement in 2008. Drs. Pietro Vernazza, Bernard Hirschel, et al asserted that a person living with HIV who was adherent to effective ART, had sustained viral suppression and had no sexually transmitted infection should not be considered sexually infectious. At the time, the statement was controversial – some considered it premature or even dangerous. In retrospect, it was a remarkably important waypoint on the road to what we now know as U=U. It forced the field to confront an implication of effective HIV treatment that many were not yet comfortable stating plainly: successful treatment was also extraordinarily powerful prevention.
  • At almost the same time, Dr. Reuben Granich et al were asking what that insight might mean at population scale. Their landmark 2009 Lancet modeling analysis examined annual voluntary HIV testing followed by immediate ART in a generalized South African epidemic. Under the model’s assumptions, HIV incidence could fall from approximately 20 per 1,000 person-years to less than 1 per 1,000 within a decade. The model was deliberately ambitious and appropriately debated. It was never proof that ART alone could simply eliminate every HIV epidemic. But it demonstrated something enormously important: treatment coverage and viral suppression could be powerful determinants of HIV incidence.

Dr. Montaner became one of the most persistent champions of taking that proposition seriously. By 2011 he was describing TasP’s accumulating evidence as a “double hat-trick,” while work from British Columbia increasingly demonstrated the population-level association between expanded ART coverage, declining community viral load, and reductions in new HIV diagnoses. Subsequent work has continued to argue that sustained ART expansion and viral suppression are fundamental components of epidemic control, a proposition that has only grown more compelling as the evidence for U=U has rendered the preventive benefit of sustained viral suppression scientifically incontrovertible.

Then came empirical evidence from Dr. Myron Cohen et al. HPTN 052 initially demonstrated a 96% reduction in genetically linked HIV transmission among serodifferent couples when ART was started early rather than delayed. HPTN 052’s final results showed a 93% reduction, with no linked transmissions observed when the partner living with HIV was stably virally suppressed. Early treatment also produced direct clinical benefits for the person living with HIV. Modeling based on HPTN 052 subsequently found early ART to be very cost-effective because it increased survival, prevented opportunistic infections and averted HIV transmissions.

The biological premise behind TasP was no longer principally a modeling proposition or an inference from observational data. It had randomized clinical-trial evidence behind it. Importantly, however, recognizing the extraordinary preventive power of ART did not require rejecting new prevention technologies. IAPAC confronted precisely that question in 2012 at our Controlling the HIV Epidemic with Antiretrovirals Summit in London. The summit’s resulting IAPAC Consensus Statement, released at AIDS 2012, embraced both approaches and called for their integration into the HIV response with PrEP as an adjunct to TasP.

That history matters to the argument I am making today. PrEP was never required to displace TasP to prove its value. We understood it as an additional – and potentially transformative – component of combination prevention. Indeed, the 2012 IAPAC Consensus Statement explicitly recognized the importance of examining the cost-effectiveness of combined TasP and PrEP strategies and cautioned that PrEP implementation would be particularly challenging where significant gaps remained in ART coverage among people already eligible for treatment.

More than a decade later, Dr. Montaner and colleagues have made the sequencing even more explicit. Their 2025 formulation is essentially generalized TasP plus focused PrEP: immediate, supported ART following HIV diagnosis, coupled with PrEP targeted to people at substantial risk of acquiring HIV. That is not anti-PrEP. It is not nostalgia for an earlier era of HIV prevention. And it certainly does not argue against long-acting PrEP, which represents an extraordinary scientific achievement that we should make available equitably and at scale.

Yet today, the almost breathless excitement around long-acting PrEP – and particularly the extraordinary potential of agents capable of providing protection for months at a time – risks subtly rearranging our priorities. The enthusiasm is justified. Long-acting PrEP can overcome adherence challenges, reduce the burden of daily pill-taking, expand prevention choice, and potentially transform HIV prevention for millions of people. We should embrace it, scale it and fight ferociously to make it affordable and accessible. But embracing PrEP innovation does not require diminishing the centrality of HIV treatment.

Indeed, earlier modeling comparing TasP with PrEP reached a more nuanced conclusion than today’s either-or rhetoric suggests. Analyses by Dr. Brian Williams et al found that the relative value of the two approaches depends heavily on HIV incidence, PrEP effectiveness, coverage and cost, with TasP favored under many epidemiological conditions and PrEP particularly valuable when concentrated among populations experiencing very high incidence. Their broader modeling suggested that high ART coverage combined with early treatment could be among the most effective and, over time, cost-effective interventions for reducing transmission, while other prevention approaches added important complementary protection.

That sounds less like an argument for choosing TasP over PrEP than an argument for deploying each where it produces the greatest individual and population benefit. The contemporary data make the case even more compelling. According to the Joint United Nations Programme on HIV/AIDS (UNAIDS), approximately 1.2 million people acquired HIV in 2025, while approximately 570,000 people died from AIDS-related illnesses. Since 2010, new HIV acquisitions have declined by 42%, while AIDS-related deaths declined by more than half. Those gains occurred during the era in which ART was massively expanded globally.

And now we are being given a grim natural experiment in what happens when that infrastructure is weakened by the shocks and aftershocks of US policy shifts and budget cuts. UNAIDS modeling estimates that sustained disruption of HIV programs could result in an additional 6 million HIV infections and 4 million AIDS-related deaths by 2029. Those projections encompass disruption to both treatment and prevention, which is precisely the point: the two are interdependent components of the same response.

There is also an uncomfortable human rights dimension to this discussion. We can become so focused on preventing tomorrow’s infections that we inadvertently devalue the lives of people living with HIV today. More than three decades after effective combination ART transformed HIV from an almost invariably fatal disease into a manageable chronic condition, hundreds of thousands of people are still dying annually of AIDS-related causes. Those deaths should offend us every bit as much as every preventable new HIV infection.

A strategy that celebrates declining incidence while tolerating avoidable AIDS-related deaths cannot reasonably be called successful. Nor should “We cannot treat our way out of the epidemic.” become shorthand for moving resources or political attention away from treatment. The phrase may be useful as a warning that treatment alone cannot substitute for prevention. It becomes pernicious when it implies that prevention innovation can substitute for treatment.

The wiser course is not another pendulum swing. It is balance – and disciplined allocation based on evidence. We need rapid diagnosis and immediate ART. We need durable viral suppression and systems capable of finding and re-engaging people who have fallen out of care. We need long-acting ART alongside long-acting PrEP. We need oral PrEP for people who prefer it, condoms for people who use them, harm reduction, STI services, and interventions addressing the social and structural circumstances shaping HIV vulnerability.

And we should increasingly ask a question that HIV politics sometimes discourages us from asking: What combination of interventions produces the greatest health benefit from every dollar available? That calculation must include infections averted. But it must also include deaths averted, years of healthy life gained, opportunistic illnesses prevented, hospitalizations avoided and secondary transmissions prevented through viral suppression. It must account for incidence in the population being served and recognize that the optimal mix of TasP and PrEP in Johannesburg may not be the optimal mix in Atlanta, Berlin, or Mumbai.

Above all, we need prevention and treatment strategies calibrated to epidemiological evidence, human need, cost-effectiveness and individual choice – not to whichever intervention currently commands the greatest enthusiasm. Long-acting PrEP may prove revolutionary. I hope it does. We should ensure that everyone who can benefit has meaningful access to it. But we should be equally impatient about the person living with HIV who remains undiagnosed, the patient who cannot obtain ART, the person lost to follow-up, the individual who has not achieved viral suppression, and the preventable AIDS-related death that becomes another statistic.

Perhaps insisting on this balance makes me unfashionable. I can live with that. I have had practice. God knows Drs. Montaner and Granich has faced their fair share of skepticism and resistance. But what I cannot accept is allowing the pendulum of HIV policy to swing according to fashion rather than evidence. The goal was never simply to prevent HIV infections. It was and remains to prevent infections, prevent suffering, prevent deaths, and enable people living with or vulnerable to HIV to live long, healthy lives. We cannot prevent our way out of that obligation any more than we can treat our way out of the epidemic.

Dr. José M. Zuniga is President/CEO of IAPAC, Fast-Track Health, and the Fast-Track Cities Institute.