A new study published in The Lancet Infectious Diseases this week highlights that drug-resistant tuberculosis (TB) is expected to increase in some high-burden countries over the next 20 years. In addition, the study suggests that person-to-person transmission will play a large role in the spread of drug-resistant TB as opposed to inadequate treatment or acquired drug resistance.

TB is the largest infectious disease killer in the world, causing 1.8 million deaths (including HIV co-infection) in 2015 alone. This new study, which was funded by the U.S. Agency for International Development (USAID) and the Centers for Disease Control (CDC), describes what could happen if there aren’t major changes made in the global disease response. For example, the study authors found that drug-resistant TB cases in four high-burden countries (India, South Africa, Russia and the Philippines) will increase by 2040.

The study also identifies some potential solutions, including strengthening infection control and contact tracing measures, as well as developing more rapid, effective diagnostic tests to detect and treat drug resistance. By investing in global health programs, the U.S. can support its own health security by preventing disease threats from spreading.

Now more than ever is the time to support global health, including the Global Fund to Fight AIDS, Tuberculosis and Malaria (Global Fund). Through its collaborative work with USAID’s TB program and other partners, the Global Fund has supported detecting and treating 16.6 million TB cases since 2002. With robust support and resources, the global community has the opportunity to move forward on the progress made against the TB epidemic, not backward.

Read more about drug-resistant TB on The Lancet Infectious Diseases, and watch the CDC’s animated infographic.