A decade and a half ago, we came together to bridge the political divide and address one of history’s worst public health crises. In 2002, 3.1 million people worldwide died of AIDS-related causes and 11 million children in sub-Saharan Africa had lost one or more parents to the disease. The AIDS epidemic was only getting worse; immediate action was necessary. 

As a progressive, Democratic congresswoman from the San Francisco Bay Area and a Republican senator from Tennessee, we were an odd pairing to tackle this emergency. But we knew that if we could find common ground, countless lives would be saved. So together, along with President George W. Bush and HIV/AIDS champions on both sides of the aisle, we created the President’s Emergency Plan for AIDS Relief, or PEPFAR, the largest legislative response to a single disease in history.

We will never know exactly how many lives have been saved by PEPFAR — by the prevention programs that halted HIV transmission, or the antiretroviral prescriptions that helped millions of people get the disease under control. But recent data suggests more than 11 million AIDS-related deaths have been prevented since the start of PEPFAR. And thanks in large part to PEPFAR’s education and treatment initiatives, nearly 16 million HIV infections have been averted worldwide since the program began.

In short, the PEPFAR model has become the gold standard for addressing large-scale epidemics. PEPFAR's impact extends far beyond immediate improvements in public health. Our investments have built regional health infrastructure and stimulated local economies. Studies have shown that compared to similar nations, countries that received PEPFAR assistance have had lower rates of political instability and violence, performed better on socioeconomic indices, and had more favorable views of the United States. PEPFAR is far more than just a public health program; it's a line of defense against extremism and instability.

And its impact is substantial and visible. For example, when PEPFAR began its work in Malawi, many pregnant, HIV-positive women were transmitting the virus to their children at birth because hospitals lacked the resources to prevent neonatal infections. Thanks to PEPFAR funding, today more than 80 percent of these women are accessing services to prevent HIV transmission to their children. This program is indeed saving lives.

Yet challenges remain. Fewer than half of children who are infected with HIV in Malawi have access to the treatment they need to survive. While PEPFAR is working, we need to expand our commitment to prevent new infections.

Consider the story of John Roberts, one of the first PEPFAR recipients in Uganda. When he received antiretroviral treatment in 2003, he was close to death. Today, John is living a normal and healthy life as a teacher in Uganda. We need more success stories like John's. 

The AIDS epidemic is far from over. We slowed the spread of the virus, but millions of lives are still cut short by this disease. Infection rates are growing in some countries and among some populations.

Even within the United States, 1.1 million people are living with HIV, and one in seven infected individuals doesn’t even know he or she has the virus. In the U.S., some populations are disproportionately at risk of contracting HIV/AIDS. In 2015, African Americans accounted for 45 percent of new diagnoses, even though they comprise just 12 percent of the population. To truly end AIDS — at home and abroad — we must address these persistent gaps in HIV prevention and care.

The United Nations believes that we can see an AIDS-free generation by the year 2030. But only if we invest in the programs that work abroad — such as PEPFAR and the Global Fund to Fight AIDS, Tuberculosis and Malaria — and here at home, such as the Ryan White HIV/AIDS Program and the Minority AIDS Initiative.

Once again, progress will require the same allegiance to policy — not politics — that launched PEPFAR in the first place. If these programs become a partisan football, the most vulnerable people in the world will pay the price. 

We are sounding the alarm, before our progress is further undermined by hardline ideology or political infighting. This World AIDS Day, we’re asking our colleagues and friends to think of the lives we’re trying to save — not the political parties to which we belong. That’s how we will end AIDS.

This story was originally featured on Devex.