JOHN CARLOS FREY: At Ward 86, a bustling outpatient HIV clinic at San Francisco General Hospital, nurse Diane Jones drops everything when this pager goes off.

It means that someone in the city just tested HIV positive.

DIANE JONES: So, I'm going to make him an appointment.

Jones is following a protocol called ‘RAPID' which is designed to get new HIV positive individuals into treatment immediately.

DIANE JONES: Just got diagnosed today, last negative was June.

JOHN CARLOS FREY: Jones scrambles to make plans for the new patient who is seen just hours later.

It's part of an ambitious plan in San Francisco to completely end new HIV infections.

Each year about 50,000 people in the United States are infected with HIV. And while the disease has moved off the front pages as treatment has made infection more of a manageable chronic condition, an estimated 13,700 people still die from AIDS in the U.S. each year.

Globally, an estimated 1.5 million people are killed. It's the 6th leading cause of death.

In San Francisco there are relatively few new HIV infections — 359 in 2013 and overwhelmingly found in gay men. It's a number that has been falling over the past eight years. But new infections haven't gone away.

Today, public health officials, doctors, and activists are increasing their efforts to bring that number all the way down to zero.

DIANE HAVLIR: We are talking about ending the HIV epidemic.

JOHN CARLOS FREY: Dr. Diane Havlir is chief of the HIV/AIDS division at San Francisco General Hospital and a founder of the city's ‘Getting to Zero' Consortium.

DIANE HAVLIR: HIV is one of the worst epidemics of its time. It's taken a huge toll on our city, a huge toll all around the world. We know how to prevent this disease, we know how to treat this disease. So why would we not want to prevent every single infection, and prevent every single death?

JOHN CARLOS FREY: In San Francisco, which has spent $400 million dollars fighting HIV over the last decade, this plan calls for controversial new drugs as well as established prevention strategies. But it starts with immediate treatment for new HIV infections.

DIANE HAVLIR: It did, okay.

JOHN CARLOS FREY: One of Dr. Havlir's patients, Jose, who is openly gay but asked that we conceal his identity because his family doesn't know about his health issue, went through the ‘RAPID' protocol when he was diagnosed with HIV almost a year ago.

DIANE HAVLIR: Say Ahhhh.

Within 24 hours of being diagnosed Jose was here at Ward 86, and days later receiving HIV medication.

JOSE: I was on medication on the third day. And undetectable within less than 30 days.

JOHN CARLOS FREY: Undetectable, meaning his HIV viral load had been reduced by medication to the point where it couldn't be detected. And the faster a new patient is undetectable, the faster he reduces his chance of transmitting the virus to others.

In San Francisco, about two-thirds of HIV positive individuals are virally suppressed, like Jose, more than double the national average. But that requires an enormous effort.

SANDRA TORRES: They might end up in the hospital, that's when we're going to meet them again.

JOHN CARLOS FREY: We followed social worker Sandra Torres on the bus as she checked up on a few patients who needed extra help keeping up with their appointments. She and other social workers are continually tracking people down.

SANDRA TORRES: We're going to knock on the door.

JOHN CARLOS FREY: In the gritty Tenderloin district we went to a single-room occupancy hotel where an HIV positive patient was staying. He's an intravenous drug user and not taking medication.

SANDRA TORRES: Hi Honey, how you doing?

JOHN CARLOS FREY: Torres dropped off an appointment reminder and I asked her about the patient afterward.

JOHN CARLOS FREY: It seems like an enormous effort for one person.

SANDRA TORRES: That's what it's gonna take, though. That is absolutely what it's gonna take.

JOHN CARLOS FREY: But in San Francisco, getting to zero is also banking on the expanded use of a new tool: a drug that protects individuals from becoming infected with HIV.

It's called Truvada.

SCOTT WIENER: If you take the pill once a day, and you take it consistently, you will reduce your risk of HIV infection by, at least, 90%, and perhaps as high as 99%.

JOHN CARLOS FREY: Scott Wiener is an elected city supervisor and a member of the ‘Getting to Zero' consortium.

SCOTT WIENER: It just makes sense for people to consider-this additional prevention tool. It made sense for me. And I'm I'm glad that I'm on it.

JOHN CARLOS FREY: Wiener, who represents the largely gay Castro district and who is gay himself, went public about his own use of the drug regimen last Fall and makes taking the once-a-day-pill part of his routine each morning.

SCOTT WIENER: My decision to disclose is really to raise awareness, so more people know about it and look into it, to try to increase access and provide momentum– for better access and to try to reduce stigma. So whatever stereotypes people have, maybe we can help break those stereotypes.

JOHN CARLOS FREY: Including the stereotypes raised by some critics that taking a pill that prevents HIV infection would lead to more promiscuous behavior.

JOHN CARLOS FREY: We're talking about a drug that in some circles has a stigma of opening the door to a free-wheeling sex society. HIV's no longer a threat and we don't have to worry about unprotected sex. Do you get any of that backlash?

SCOTT WIENER: There are some people who have that view. And it's really the same argument as when people would argue if you give women access to the birth control pill, you're just gonna encourage them to be promiscuous.

Or if you vaccinate young girls against HPV you're gonna turn them into, I think one person said, “You'll turn them into nymphomaniacs.”

Or if you give sex ed to high-school students or middle-school students you're gonna encourage them to be promiscuous. These are completely specious arguments. This is about giving people every tool available to protect their sexual health.

JOHN CARLOS FREY: The use of Truvada for HIV prevention was approved by the FDA in July 2012. The Centers for Disease Control issued guidelines in May of last year recommending the drug for those with substantial risk of HIV infection.

In San Francisco, researchers believe that wider adoption of the drug could dramatically reduce new HIV infections, but so far only a few thousand San Franciscans have taken the drug in the last year.

So why isn't the use of this drug more widespread?

There are some side effects, as well as speculation that doctors may be hesitant to prescribe a preventative drug to healthy patients, and then there's the price. Although covered by most insurance, Truvada, is listed at more than $1000 a month

Even so, it's not nearly the solution that its proponents make it out to be according to Michael Weinstein, president of the AIDS Healthcare Foundation, one of the largest AIDS organizations in the world.

MICHAEL WEINSTEIN: I think the evidence shows that it is not a good public health strategy.

JOHN CARLOS FREY: Why is that?

MICHAEL WEINSTEIN: Well, because people don't adhere.

JOHN CARLOS FREY: While studies have shown that the regimen can be over 90% effective when taken everyday, Weinstein points out that the efficacy drops off when people miss their daily dose. He also says that relying on a pill instead of a condom may lead to a rise in other sexually transmitted diseases.

MICHAEL WEINSTEIN: The motivation that people have for taking Truvada is to be able to have sex without a condom.

JOHN CARLOS FREY: Do you think that people don't want to wear condoms either?

MICHAEL WEINSTEIN: I think men in general don't wanna wear condoms. That's just an absolute truth. I mean, and it's not surprising. But, you know, we don't wear seatbelts either, you know, or helmets or a lot of other things. But they're a necessity.

JOHN CARLOS FREY: So wouldn't it be better then, to just take a pill every day instead of worrying about transmitting H.I.V.?

MICHAEL WEINSTEIN: You know what? If it was guaranteed that everybody would take it every day as prescribed. Obviously our attitude about it would be completely different if we didn't have to rely on the person to take that pill every single day.

JOHN CARLOS FREY: San Francisco Department of Public Health Chief Barbara Garcia says the city is working to make sure the drug is taken as prescribed, and that doesn't lead to other safe sex practices being abandoned.

BARBARA GARCIA: We have already started in trying to educate young people, particularly about this. And that's one of the challenges of having even if we had a cure, that would be the same challenge we would have.

JOHN CARLOS FREY: Do you see that happening though? I mean, obviously, if you're having unsafe sex, you're going to be transmitting other sexually-transmitted diseases here

BARBARA GARCIA: And, in fact, we've seen a little bit of a rise in S.T.D. here in San Francisco. And we're addressing that as well.

JOHN CARLOS FREY: It's not clear that an increase in STDs is related to an increase in the use of Truvada. And Garcia is committed to the drug regimen being a part of ‘Getting to Zero' in San Francisco. And believes that the city's approach to ending HIV, including the lives and money it will save, will eventually trump any controversy.

JOHN CARLOS FREY: You can prove to them that you can save money by your model?

BARBARA GARCIA: Absolutely. An H.I.V. prevention versus an H.I.V. positive client in care, yes, we can.

JOHN CARLOS FREY: San Francisco has made tremendous advances in battling an epidemic that his this city harder than most. And according to Dr. Havlir actually getting to zero is within reach.

DIANE HAVLIR: I think we would all acknowledge that it is going to be difficult to do, but I think if, as we say, if anybody can do it, we think that we can show people how it can be done starting here.