字幕表 動画を再生する 英語字幕をプリント The world is getting closer to achieving one of the most important public health goals of our time: eradicating HIV. And to do this, we won't even have to cure the disease. We simply have to stop HIV from being transmitted until eventually it fizzles out. Once, this goal would have seemed impossible. HIV has caused millions of deaths and is one of the most devastating diseases that humanity has ever known. But we're now at a point where new advances such as one-pill, once-a-day medications are helping us tackle HIV in effective ways. HIV is a retrovirus– meaning it integrates copies of itself into an infected cell's DNA, allowing it to replicate and infect other cells. HIV has evolved numerous ways to evade the human immune system, which makes it difficult to cure. But by developing ways to block HIV replication, we can stop the spread of HIV itself. That's where antiretrovirals– a.k.a. ARVs– come in. ARVs are a group of drugs which work in different ways to combat HIV. Some block HIV's access into immune cells, and others work by stopping the virus itself from replicating. ARVs also work preventatively in people who don't have HIV. This type of approach is called pre-exposure prophylaxis, or PrEP. PrEP works by accumulating in a person's body and preventing HIV from establishing itself. That means an HIV-negative person who may be at risk of contracting the disease can take certain ARVs to protect themselves, before they become exposed. Here's where it gets especially interesting: In people with HIV, ARVs can also dramatically reduce HIV transmission. This is called “Treatment as Prevention.” On a global scale, this has the potential to end the HIV epidemic. It's based on the idea that someone with HIV who takes ARV's can lower the virus level in their bodies until it becomes undetectable. That doesn't mean the virus is gone; it could still be lurking within cells, ready to reactivate if treatment stops. But so long as it's kept dormant with drugs, HIV remains undetectable. And when HIV is undetectable, it's untransmittable, too. In theory this means that by testing everyone who's at risk of HIV and treating those who test positive, we could stop transmission and eventually eradicate HIV. In the real world, however, things are more complex. Many at-risk HIV negative people across the world do not have access to PrEP or ARVs, and those who are HIV positive may experience challenges to taking ARVs. These problems are often greatest in countries where the burden of HIV is highest. Getting these medications depends on access to a functioning healthcare system– and this isn't something everyone has. That's part of the reason why stopping the spread of HIV for good will require a significant investment of resources to improve those systems. One study carried out by the UNAIDS estimated that between 20-30 billion dollars per year would be needed to achieve a nearly 90% reduction in new HIV infections by 2030. This investment would ensure more people would get tested in the first place, and more would be able to access and maintain treatment. Achieving this goal and improving healthcare in general is in everyone's best interest, from individual people to society as a whole. We have roadmaps that could allow us to bring the HIV epidemic to an end in the near future, with the possibility of eradicating the disease altogether several generations in the future. In the period from 1996 to 2017 we almost halved the number of new HIV infections, and for the millions of people who still live with the virus, ARV treatments enable most to lead long and healthy lives. With continued and increased investments, we can get transmission rates low enough to end HIV once and for all. A world without HIV is no longer inconceivable: it's closer than ever.