AIDS is most common in sub-Saharan Africa, particularly in the southern part of the continent. Africa accounts for roughly 71% of all people living with HIV worldwide, with a prevalence rate of 2,731 per 100,000 people, nearly six times higher than the next most affected region. As of the end of 2024, an estimated 40.8 million people were living with HIV globally, and the majority live in a cluster of countries including South Africa, Mozambique, Lesotho, Zimbabwe, and Namibia.
Sub-Saharan Africa Carries the Heaviest Burden
Africa had roughly 26.2 million people living with HIV as of 2019, dwarfing every other region. The Americas had about 4 million, Asia roughly 4.5 million, and Europe around 2.2 million. But raw numbers only tell part of the story. Africa’s prevalence rate of 2,731 per 100,000 is in a category of its own. The Americas, the second-highest region by that measure, had a rate of 391 per 100,000.
Within Africa, the epidemic concentrates in the south. Countries like Lesotho, Eswatini, and South Africa have some of the highest infection rates on the planet, with adult prevalence sometimes exceeding 20% of the population. Central and West Africa are also heavily affected but generally at lower rates than the southern belt.
Why Southern Africa Is Hit So Hard
There is no single explanation for why southern Africa became the global epicenter. Researchers point to a combination of biological, behavioral, and structural factors that reinforced each other over decades. Labor migration played a major role: men leaving home for extended periods to work in South African mines increased the number of sexual partnerships across wide geographic areas, seeding the virus into new communities. Young women in the region have the highest infection rates of any age or sex group, partly driven by age-disparate sexual partnerships.
Biological factors compound the problem. Genital inflammation and co-infections significantly raise the odds of acquiring HIV during sex. Certain intravaginal practices common in parts of the region also increase susceptibility. At the population level, even modest increases in individual risk multiply rapidly when prevalence is already high, because any new sexual contact is more likely to involve someone with an undetected or untreated infection.
Health system gaps have made things worse. Many countries in the region have struggled with inconsistent access to treatment, drug stockouts, and low retention in care programs. When people start treatment but can’t stay on it reliably, the virus rebounds and remains transmissible. Achieving widespread viral suppression, which effectively prevents transmission, requires an unbroken chain from testing to treatment to long-term medication access. Breakdowns at any step allow the epidemic to persist.
Eastern Europe and Central Asia: The Fastest Growth
While Africa has the highest total numbers, eastern Europe and central Asia have the fastest-growing epidemic. New infections in the region rose 48% over the past decade, reaching roughly 160,000 new cases in 2021. AIDS-related deaths climbed 32% in the same period. This is the only major region where the epidemic is clearly getting worse rather than better.
The epidemic there initially spread largely through shared needles among people who inject drugs, but heterosexual transmission has since become the primary route. Despite this shift, harm reduction programs like needle exchanges and medication-assisted treatment for opioid dependence remain extremely limited. Regional coverage for opioid treatment sits around 4%, far below international targets of 50%. Some countries, including Uzbekistan and Turkmenistan, offer no such programs at all.
Stigma plays a significant role, particularly against gay and bisexual men, making it harder for people to seek testing and treatment. Preventive medication that can stop infection before exposure is largely unavailable across the region due to lack of government funding and limited health infrastructure. Decades of political neglect allowed transmissions to accelerate before public health responses could catch up.
HIV in the United States
Within the United States, the South carries a disproportionate share of the epidemic. In 2022, 52% of all new HIV diagnoses (nearly 19,800 cases) occurred in Southern states, more than the West, Northeast, and Midwest combined. The West accounted for 21%, while the Northeast and Midwest each contributed about 13%.
Federal efforts to reduce new infections have focused on 48 specific counties, Washington, D.C., and San Juan, Puerto Rico, where more than half of all U.S. diagnoses were concentrated in recent years. Seven additional states with high rural HIV burden are also targeted. The geographic concentration means that someone’s risk in the U.S. varies dramatically by where they live, with urban areas in the South and a handful of large cities elsewhere accounting for a large share of new cases.
Where Treatment Access Falls Short
Antiretroviral therapy has turned HIV from a death sentence into a manageable chronic condition for millions of people. But access is uneven. The Eastern Mediterranean region has the lowest treatment coverage of any WHO region, at just 28%. Low political priority, cultural stigma, weak health systems, and insufficient advocacy all contribute to the gap. By contrast, many countries in eastern and southern Africa have dramatically expanded treatment access over the past 15 years, despite having the highest case counts.
Treatment access matters not just for individual survival but for controlling the epidemic at a population level. People with fully suppressed viral loads from consistent treatment effectively cannot transmit the virus. When treatment coverage drops, transmission rebounds quickly. One recent estimate found that a 90-day pause in global HIV funding and the resulting treatment interruptions could cause over 100,000 excess deaths in a single year.
Global Deaths Are Falling, but Unevenly
Globally, 630,000 people died from HIV-related causes in 2024, a 54% reduction from 1.4 million deaths in 2010. That progress is real and largely driven by expanded treatment access in the hardest-hit African countries. But the decline is far from universal. Eastern Europe and Central Asia saw deaths rise over the same period, and regions with low treatment coverage continue to lose people to a disease that is, with consistent medication, entirely survivable. About 75,000 of the deaths in 2024 were children under 15, a group that remains underserved by testing and treatment programs in many parts of the world.