This weekend, we observe World Tuberculosis (TB) Day (Sunday, March 24), a day to remember that the global burden of TB remains enormous, particularly among people with HIV/AIDS, among whom TB is the leading cause of death, worldwide.
According to the World Health Organization (WHO), in 2011, 1.4 million people died from TB, including 430,000 deaths among people who were HIV-positive. TB is also one of the top killers of women around the globe, with 300,000 deaths among HIV-negative women and 200,000 deaths among HIV-positive women in 2011.
TB is also a health threat among people living with HIV in the United States. In 2011, the Centers for Disease Control and Prevention (CDC) estimates that 6% of all TB cases in the U.S. and 10% of TB cases among people aged 25–44 occurred among people who are living with HIV.
Thankfully, the rate of TB is declining in the U.S. According to the CDC, the number of TB cases reported annually has decreased since its peak in 1992. In addition, most cases of TB disease in the U.S. now occur among immigrants; in 2011, a total of 62% of reported TB cases in the United States occurred in foreign-born persons (CDC). (Read more about TB trends in the U.S. in the March 22, 2013 issue of CDC’s Morbidity and Mortality Weekly Report (MMWR).)
However, tuberculosis remains a serious concern for people living with HIV/AIDS. That’s because a dangerous synergy exists between HIV and TB, such that people who have a suppressed immune system due to HIV infection are much more likely to develop active TB disease if they are exposed to the TB bacteria. Also, active TB infection appears to increase HIV replication among co-infected persons. Therefore, the populations of people who are infected with these two pathogens often overlap.
Or, as an historical leader in the field of HIV (Dr. Jim Curran) once observed: “HIV and TB hang out together and they are a bad influence on each other!”