The World Health Organization (WHO) has released new guidelines for AIDS treatment around the world. The guidelines come with a hefty price tag but may save millions of lives around the world and make a real dent in the HIV epidemic.

The new guidelines, released Sunday at the meeting of the International AIDS Society in Kuala Lumpur, Malaysia, recommend earlier treatment for HIV-positive adults as well as treatment right after diagnosis for all children under age five, pregnant women, individuals with tuberculosis or hepatitis B, and adults who have uninfected partners.

While many wealthier countries already follow similar guidelines, this is not the case in some places where HIV rates are there highest. WHO says that expanding treatment would add about 10 percent to the $23 billion that’s already spent on HIV treatment each year but estimates it could prevent three million deaths and avert 3.5 million new infections by 2025.

The new guidelines suggest that HIV-positive adults start taking antiretroviral (ART) medication when their CD4 cell count drops to 500, which is still in the healthy range. (People with healthy immune systems have a CD4 cell count between 500 and 1,600.) CD4 cells, also referred to as T cells, are an important part of the immune system that help people fight off infection. AIDS is diagnosed when a person with HIV has a CD4 count of 200 or less. The previous guidelines postponed treatment until a CD4 count of 350. The WHO, however, believes that starting while a person has a healthy immune system will not only keep them healthy longer but will also prevent infections, because people on ARTs also have lower viral loads, which makes the virus much less contagious.

The new guidelines also suggest that all adults starting ART be given a new medicine that combines three drugs—tenofovir, lamivudine (or emtricitabine), and efavirenz—into a single pill that is taken once a day. This combined medication is easier to take and less expensive. In countries with negotiated lower prices, this pill can be taken once a day for a year for approximately $127.

In a press release, the WHO explained the change in the guidelines:

WHO has based its recommendation on evidence that treating people with HIV earlier, with safe, affordable, and easier-to-manage medicines can both keep them healthy and lower the amount of virus in the blood, which reduces the risk of passing it to someone else. If countries can integrate these changes within their national HIV policies, and back them up with the necessary resources, they will see significant health benefits at the public health and individual level.

The organization’s director-general, Dr. Margaret Chan, went on to say, “With nearly 10 million people now on antiretroviral therapy, we see that such prospects—unthinkable just a few years ago—can now fuel the momentum needed to push the HIV epidemic into irreversible decline.”

Still, it will be challenging to get widespread access and compliance. Currently, only about 60 percent of individuals who are eligible for the drugs are getting them, and the guidelines increase the number of people eligible by about nine million. Moreover, it can difficult to get some people to continually take their drugs, especially if they have yet to feel ill. Dr. Sarah Fidler, an HIV expert at Imperial College London who is doing research in Africa, told the Boston Herald, “For people struggling with other issues like poverty, taking pills for a disease that isn’t making them sick yet might not seem like the most important thing in the world. This is not going to be as simple as just giving drugs to everybody.”

However, WHO’s HIV-AIDS director, Dr. Gottfried Hirnschall, said the new guidelines could have a tremendous impact. He summed it up this way when talking to the BBC: “It will be very difficult to end AIDS without a vaccine—but these new guidelines will take us a long way in reducing deaths.”