- HIV infections are projected to decrease 32% among U.S. men who have sex with men by 2035
- Researchers developed a model to identify steps to end the HIV epidemic among this population
- With intensified prevention, testing and treatment, infections could be reduced 91% by 2035
Effective HIV treatment has transformed what it means to live with HIV. Many people who initiate HIV treatment (antiretroviral therapy; ART) and take their medication as directed achieve a suppressed level of HIV in their blood. Viral suppression allows the immune system to recover sufficiently so that the risk of developing AIDS is greatly reduced. The power of ART is so profound that scientists project that many people with HIV who use ART will live well into their senior years.
Another benefit of suppressing HIV with ART is that the virus cannot be passed on to sexual partners. Thus, ART itself has the power to reduce the spread of HIV.
HIV medicines are also used as a form of pre-exposure prophylaxis (PrEP), whereby they can be taken by people without HIV to protect them from exposure to the virus. PrEP is highly effective when used as directed and it also has the potential to decrease the spread of HIV within cities, regions and countries.
What’s more, in cases where exposure does occur, post-exposure prophylaxis (PEP) taken within 72 hours of exposure is highly effective at preventing HIV infection.
Mapping HIV at Harvard
According to a team of scientists at Harvard University, “we have the tools to decrease HIV transmissions, but they are not reaching everyone who needs them.” The researchers highlighted data on the U.S. HIV care cascade from the year 2022, showing the following distribution:
- 87% of people with HIV in the U.S. were aware of their diagnosis
- 66% of these people were engaged in care and taking ART
- 57% of people on ART were virally suppressed
These rates are not ideal. The World Health Organization (WHO) called for cities, countries and regions to achieve a distribution of 90-90-90 by 2020 and 95-95-95 by the end of 2025.
The Harvard scientists noted that although gay, bisexual and other men who have sex with men (gbMSM) represent a small proportion of the overall U.S. population, they constituted 71% of people with HIV in 2022.
The researchers stated that they sought to “quantify the magnitude and combination of improvements in testing, care and prevention needed to meet [the goal] of reducing HIV transmissions by 90% for gbMSM.”
They used data from well-validated sources and modified an existing computer model. This enhanced model was then used to project, or simulate, the impact of different strategies on the trajectory of the HIV epidemic in the U.S. to the year 2045.
The scientists compared interventions at the current rate of implementation vs. intensified application of more widely available HIV testing, followed by improved linkage to care and improved engagement in care among people with HIV. They also modeled the impact of PrEP and increasing PrEP coverage over time.
The research team focused on gbMSM because this group is disproportionately affected by the HIV pandemic in the U.S.
Results
Maintaining the status quo
If the current rate of deployment of testing, ART and PrEP use continues, the scientists found that the following changes would occur:
- a 32% decrease in annual HIV infections by 2035 and a 41% decrease by 2045
Intensified engagement in care and treatment
The researchers compared different interventions and found that the ability to keep people engaged in care (maintaining regular visits to healthcare providers, filling prescriptions on time and taking ART as directed) would likely have a significant impact in reducing new HIV infections. Their model predicted that if 90% of people were engaged in care and treatment, there would be a 57% reduction in new cases of HIV by 2035. By the year 2045, new infections would fall by 68% with a continued high level of engagement in care and treatment.
Increasing use of PrEP
The model estimated that if 90% of gbMSM who were at high risk for HIV used PrEP, this would likely result in a 58% decrease in new HIV infections by 2035 and a 69% decrease by 2045.
The power of advancing different interventions
The simulation suggested that intensifying engagement “throughout the [HIV cascade of care]” could, in theory, end the HIV epidemic as a public health concern within the next 20 years. By “intensifying engagement,” the researchers mean that 98% of people who test positive would be linked to care; 98% of people linked to care would be engaged in care; and 98% of people engaged in care would achieve viral suppression.
This would likely result in the following:
- 82% reduction in HIV transmissions by 2035
- 88% reduction in HIV transmissions by 2045
The simulation also suggested that combined with the interventions involving care and treatment, increased access and adherence to PrEP would likely lead to dramatic reductions in new cases of HIV, as follows:
- 89% reduction in HIV transmissions by 2035
- 93% reduction in HIV transmissions by 2045
Thus, in theory, intensified efforts across the HIV cascade of care and expanded use of PrEP could end HIV as a public health concern in the U.S. by 2035.
The sooner intensified efforts are implemented, the sooner HIV could be ended as a public health issue. The researchers found that if intensified efforts were implemented immediately, new HIV transmissions would fall by 91% by 2035. If intensified efforts were gradually implemented over the coming decade, new HIV transmissions would be reduced by 86% in 2035.
The importance of ongoing viral suppression and HIV testing
The researchers noted that in the U.S. “an estimated 62% of transmissions in 2016 and 54% in 2019 originated from individuals diagnosed but not virally suppressed.” They added that as of 2022, “approximately 32% of diagnosed gbMSM with HIV remain unsuppressed.”
The present simulation study did not explore the reasons why people who were diagnosed with HIV had not achieved viral suppression, as the scientists cited previous research on this issue. However, the study points to the need to support people with HIV in accessing care and treatment and adhering to their treatment regimens. There may be a role for financial subsidies to help people access ART and medical care, as well as for increased access to long-acting ART formulations and psychosocial support.
The researchers added that figures from 2022 indicate that “only 13% of gbMSM with HIV were undiagnosed, so testing and linkage improvements would affect a small group.”
Missing in the analysis
The researchers stated that their ambitious goals also require interventions for people who use drugs and for heterosexual people.
Proposed catastrophic funding cuts in the U.S.
The researchers noted: “HIV funding in the U.S. is not secure. A federal spending bill proposed ending all [efforts to end the HIV pandemic in the U.S.], and 2025 federal budget proposals included US $880 billion in cuts to Medicaid, the largest HIV care payer in the U.S. Federal funding freezes also threatened Ryan White Care Act programs, which provide care, medications and essential services for people living with HIV. These funding threats work against the large-scale programmatic improvements that are needed to achieve the ambitious goals [required to end HIV as a public health issue], which makes reaching them even less likely.”
In Canada
The latest figures from the Public Health Agency of Canada (PHAC) are not encouraging. According to PHAC, “in 2024, an estimated 2,517 new infections occurred, representing a 22.8% increase from 2022, when 2,050 infections were recorded. This translates to approximately seven people being newly infected with HIV each day across the country.”
PHAC states that “in 2024, there were an estimated 70,900 people living with HIV” distributed across the simplified cascade of care as follows:
- 91% of people with HIV were diagnosed
- 86% of people diagnosed were taking ART
- 96% of people taking ART were virally suppressed
Canada has much work to do to achieve the 2025 World Health Organization goals of 95-95-95.
Like the U.S., Canada also has the tools needed to end HIV as a public health issue in the coming decade. However, without political will and enhanced funding, new cases of HIV will continue to increase, erasing progress made over the past decade.
—Sean R. Hosein
Resources
PHAC. Report on key indicators: Canada’s Progress Toward Ending the HIV Epidemic. 24 July 2026. Available at: https://health-infobase.canada.ca/hiv-treatment/
REFERENCES:
- Scott JA, Spaeth H, Chi KK, et al. Ending the HIV epidemic in the United States among men who have sex with men: A modeling analysis. Open Forum Infectious Diseases. 2026 Aug 3;13(8): ofag386.
- PHAC. Report on key indicators: Canada’s Progress Toward Ending the HIV Epidemic. 24 July 2026.
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