So today, I want to talk about a new approach, an approach that I feel will not only help us know why babies are dying, but is beginning to completely transform the whole field of global health. It’s called “(1) .” For me, precision medicine comes from a very special place. I trained as a cancer doctor, an oncologist. I got into it because I wanted to help people feel better. But too often my treatments made them feel worse. I still remember young women being driven to my clinic by their moms — adults, who had to be helped into my exam room by their mothers. They were so weak from the treatment I had given them. But at the time, in those front lines in the war on cancer, we had few tools. And the tools we did have couldn’t (2) between the cancer cells that we wanted to hit hard and those healthy cells that we wanted to preserve. And so the (3) that you’re all very familiar with — hair loss, being sick to your stomach, having a suppressed immune system, so infection was a constant threat — were always surrounding us. And then I moved to the (4) . And I got to work on a new approach for breast cancer patients that could do a better job of telling the healthy cells from the unhealthy or cancer cells. It’s a drug called Herceptin. And what Herceptin allowed us to do is to precisely target HER2-positive breast cancer, at the time, the scariest form of breast cancer. And that precision let us (5) the cancer cells, while sparing and being more gentle on the normal cells. A huge breakthrough. It felt like a miracle, so much so that today, we’re harnessing all those tools — big data, consumer monitoring, (6)_ and more — to tackle a broad variety of diseases. That’s allowing us to target individuals with the (7) at the right time. Precision medicine revolutionized cancer therapy. Everything changed. And I want everything to change again. So I’ve been asking myself: Why should we limit this smarter, more precise, better way to tackle diseases to the rich world? Now, don’t misunderstand me — I’m not talking about bringing expensive medicines like Herceptin to the developing world, although I'd actually kind of like that. What I am talking about is moving from this (8) for individuals to tackle public health problems in populations. Now, OK, I know probably you’re thinking, “She’s crazy. You can’t do that. That’s too ambitious.” But here's the thing: we’re already doing this in a limited way, and it's already starting to make a big difference. So here's what's happening. Now, I told you I trained as a cancer doctor. But like many, many doctors who trained in San Francisco in the 80s, I also trained as an AIDS doctor. It was a terrible time. AIDS was a death sentence. All my patients died. Now, things are better, but HIV/AIDS remains a terrible (9) . Worldwide, about 17 million women are living with HIV. We know that when these women become pregnant, they can transfer the virus to their baby. We also know in the absence of therapy, half those babies will not survive until the age of two. But we know that antiretroviral therapy can virtually guarantee that she will not transmit the virus to the baby. So what do we do? Well, a one-size-fits-all approach, kind of like that blast of chemo, would mean we test and treat every pregnant woman in the world. That would do the job. But it’s just not practical. So instead, we target those areas where HIV rates are the highest. We know in certain countries in sub-Saharan Africa we can test and treat pregnant women where rates are highest. This (10) to a public health problem has cut by nearly half HIV transmission from mothers to baby in the last five years. (Applause) Screening pregnant women in certain areas in the developing world is a powerful example of how precision public health can change things on a big scale.