Through the worst of an epidemic affecting multiple generations of South Africans, modern medicine has saved some 2.8 million years of life — during just the past decade.

Since 2004, the increased use of antiretroviral therapy (ART) to treat HIV infections has given millions of patients a longer chance at healthy living. Michael D. April, of the San Antonio Uniformed Services Health Education Consortium, expects ART to save nearly 18 million years of life by 2030.

"We hope that this study reminds stakeholders of the astounding efficacy of the global ART rollout while simultaneously invigorating efforts to redouble commitments toward expanding the availability of ART," April said in a statement.

As leaders marked World AIDS Day on Sunday, South Africa’s epidemic remained the largest with an estimated 5.6 million people infected with HIV in 2011, according to the United Nations. About half of those South Africans qualify for treatment with ART under current guidelines for international relief efforts. Although wildly successful, the supply of antiretroviral drugs remains limited, with one-third of those medically eligible presently denied treatment.

In the new study, April and his colleagues calculated the possible health benefits of wider availability of ART throughout the country. Recent progress in preventing and treating HIV must be protected by continued international investment in fighting the infectious disease, April said. "Policymakers have the power to magnify the future trajectory of survival gains further still by pursuing more aggressive HIV testing and treatment strategies," he said. "Increased case identification, early ART initiation, and expanded treatment options might catapult our conservative survival projections even further."

Despite earlier policy decisions to limit increases of the treatment, the country’s aggregate survival benefit — over just eight years — mirrors the benefit seen in the United States since the introduction of ART in 1989, according to Sten H. Vermund, of Vanderbilt University. "The magnitude of the benefit of South African ART-based programs is astounding [and]… will continue to bolster this essential investment for the future of the African continent,” he wrote in an editorial accompanying the study on Tuesday.

The continued success of ART in South Africa depends on financial funding for not only the maintenance of 1.4 million patients receiving treatment but an expansion to unserved populations. In the country with the world’s worst HIV epidemic, only half the people have tested for the disease.

Thus, more “life years” have yet to be saved, according to April’s colleague, Rochelle P. Walensky, of Harvard Medical School and Massachusetts General Hospital. "Our results suggest that rather than a debate over continuation of current funding commitments for the global response to HIV, policymakers and researchers should be examining strategies to most effectively and efficiently expand HIV testing and treatment efforts, to help increase future potential survival gains," she said.

On Sunday, President Barack Obama announced $100 million in new funding to develop new therapies for HIV/AIDS. “The United States should be at the forefront of the discoveries how to put HIV in long-term remission without requiring lifelong therapies,” Obama said. “Or, better yet, eliminate it completely."

The money for the U.S. National Institutes of Health comes in addition to international funding pledges of $5 billion over two years for the Global Fund to Fight AIDS, Tuberculosis, and Malaria. In that scheme, the U.S. provides $2 matching donations for every $1 collected from other sources. However, Obama withstood international pressures to out-do former President George W. Bush’s five-year $15 billion commitment in 2003 — the President’s Emergency Plan for AIDS Relief.

Instead, Obama announced the new $100 million in HIV/AIDS funding would be “reprioritized” from elsewhere in the budget, though he didn’t say where. Overall last year, the U.S. government spent $27.7 billion on HIV/AIDS, on mostly prevention and treatment — with the new money to focus on finding a cure.

Although some find paucity in the president’s new commitment, others find value. Rep. Jim Hines, D-Conn., says international experts believe in the power of a well-targeted $100 million shot. "An AIDS-free generation is not yet upon us, but may not be far off and we must keep working to achieve this goal,” he said in a statement.