The World Health Organization (WHO) last month issued new treatment and prevention guidelines for HIV that suggest all patients who test positive for the virus be put on antiretroviral drugs right away and that those at high risk for the virus be offered preventive drug therapy.

San Francisco provides a great example of how this approach can work, as the New York Times reported Monday. San Francisco, which was once a hotbed of the national HIV and AIDS epidemic—the city saw 1,641 die from AIDS in 1992—saw just 302 new HIV infections last year and 177 HIV-positive San Franciscans died (some from unrelated causes). A multi-prong approach that gets patients into treatment immediately, offers pre-exposure prophylaxis for those at most risk, and helps people find and keep health insurance is responsible for the city’s success.

The city adopted the test-and-treat part of the model in 2010. That increased the availability of testing services and created a program called Rapid, which connects patients who test positive with doctors who can see them right away. Those who don’t have health insurance can meet with a social worker who helps them apply for public health coverage. The program will even provide car fare if necessary.

This strategy was met with some resistance from doctors who thought the side effects of the drugs were too harsh for people whose immune system were not yet compromised and worried that people who still felt healthy would be unlikely to stick to a demanding drug regimen.

“We were accused of medicalizing HIV,” Dr. Grant Colfax, who was the city’s director of HIV services in 2010, told the New York Times. “Which I found ironic.”

Getting people who test positive immediate treatment is not just about their own health, it’s about preventing them from spreading the disease. When taken regularly, antiretroviral drugs can reduce the level of virus in a person to the point that he or she is no longer contagious.

Such patients are said to be virally suppressed. In San Francisco, 82 percent of residents with HIV are in care and 72 percent are suppressed. This far outstrips performance nationally. As of 2012, the Centers for Disease Control and Prevention estimated that 39 percent of HIV-positive Americans were in treatment and only 30 percent were taking their drugs frequently enough to be considered suppressed.

In 2013, after the Food and Drug Administration (FDA) approved Truvada—a pill that combines two HIV drugs—for use as pre-exposure prophylaxis (PrEP), San Francisco added that to its approach. PrEP has been found to be highly successful. A study of 657 Kaiser Permanente patients on Truvada found that none of them contracted HIV over a two-year period, as Rewire recently reported.

The method has its critics, however, because condom use among these men went down and about half of them contracted another sexually transmitted infection (STI) such as gonorrhea or chlamydia. Nonetheless, Dr. Susan Boochbinder, head of HIV research for the city’s health department, says it would be ridiculous not to offer PrEP for fear that patients will get other STIs.

“Denying PrEP to our patients because they might have unsafe sex makes about as much sense as our colleagues who treat high cholesterol denying their patients statins because they might eat more ice cream,” Boochbinder told the New York Times.

San Francisco’s model includes intensive follow-up to ensure that patients—especially those at most risk, such as the homeless—stay in treatment.

This model cannot be replicated in low-income areas, especially in the developing world where donor contributions for AIDS has been flat since 2009.

San Francisco is a wealthy city. The lack of affordable housing in the city has forced low-income people out, meaning many residents with HIV have higher incomes and access to health insurance. The tech boom means that the city has a large budget that allows it to fill in HIV-funding funding gaps where state and federal budgets fall short.

Still, there is a lot to be learned from this program.

“I love the San Francisco model. If it keeps doing what it’s doing, I have a strong feeling that they will be successful at ending the epidemic as we know it,” Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, told the New York Times. “Not every last case—we’ll never get there—but the overall epidemic. And then there’s no excuse for everyone not doing it.”