In October, the World Health Organization announced that tuberculosis had overtaken HIV/AIDS as the number one infectious killer in the world. Does this shift in global disease patterns mean that action around World AIDS Day, on Dec. 1, is now somehow less crucial? Not at all. HIV and TB are a pair of very nasty bedfellows: Globally, people living with HIV are 26 times more likely to develop active TB than those without HIV. Ending this dual scourge will require increased investment in TB research and control programs, as well as continued scale-up of effective HIV treatment programs.

HIV and TB are inextricably linked. People living with HIV have weaker immune defenses, meaning they can harbor and spread TB, including the especially expensive and deadly drug-resistant forms of the disease. For TB, existing antibiotics can cure most cases within six months, but drug-resistant forms are much more expensive and difficult to treat, taking closer to two years to cure.  The stronger antibiotics needed to fight drug-resistant strains can also have harsh side effects, making their regimens harder to follow.

The devastating effects of HIV coinfection with TB were apparent a decade ago in Tugela Ferry, a rural area of KwaZulu Natal, South Africa, where an extensively drug-resistant strain of TB was identified in 53 people, all of whom were HIV-positive. Fifty two of those 53 people with that drug-resistant strain of TB died within months. Once HIV weakens the immune system, it creates a perfect environment for active TB to take hold, creating a situation even more deadly than either disease on its own.

Luckily, we have proven methods to prevent, detect and treat HIV. Antiretroviral drugs not only allow people to keep living healthy and productive lives, but can also prevent mother-to-child transmission and suppress viral loads to avert further spread. Fewer new cases of HIV equate to fewer easy targets for TB.

We know how to fight HIV and TB: We just need to do more of it. HIV and TB treatment and prevention programs have been scaled up significantly since the devastating drug-resistant TB incident in Tugela Ferry a decade ago. Programs such as the President’s Emergency Plan for AIDS Relief and the Global Fund have enabled vast expansion of lifesaving efforts. Despite these advancements, more than half of people with HIV still lack access to the antiretroviral drugs they need to stay healthy, keep working, support their loved ones and prevent transmission of the virus to others. By finding and properly treating cases of TB, we can prevent the spread of the bacteria and impede drug resistance.

Scrolling through social media or reading over the headlines, it is easy to feel disappointed by all of the problems that we aren’t sure how to solve. On World AIDS Day, we have a chance to celebrate and scale-up solutions that have already proven successful. We have an opportunity now to drastically reduce HIV within a decade, and significantly reduce the occurence of death from TB as a result. However, this progress has been slowed as foreign aid initiatives, which account for less than one percent of the U.S. budget, have inexplicably been cut by Congress over the last five years.

Several presidential candidates, including Hillary Clinton LAW ’73 and Bernie Sanders, have already committed to achieving 30 million people on antiretroviral treatment by 2020 if elected. These promises resulted in part from a national student movement, in which individuals from different universities united behind the same target. Let’s call on all current presidential candidates and our members of Congress to commit to funding PEPFAR and the Global Fund. Let’s see if our politicians will commit our dollars to programs that are already proven to end not only the spread of infectious disease, but also the suffering and lost productivity that accompany these illnesses. Tell our politicians — the world is waiting, and we are watching.

Emily Briskin is a 2015 graduate of Pierson College and a student at the Yale School of Public Health concentrating in Epidemiology of Microbial Disease and Global Health. Contact her at emily.briskin@yale.edu .