Rethinking tuberculosis and human immunodeficiency virus as a syndemic: Implications for global prevention and care.

Abstract

Tuberculosis remains the leading infectious cause of death among people living with human immunodeficiency virus (HIV). An estimated 10.7 million people developed tuberculosis worldwide in 2024, including 619,000 people living with HIV, while tuberculosis caused an estimated 150,000 deaths among people living with HIV. The two epidemics are better understood as a syndemic than as a co-infection because they concentrate in the same populations, interact biologically, and share adverse social conditions. Evidence indicates that integrating tuberculosis and HIV services shortens the time to antiretroviral therapy initiation but has not demonstrated a mortality benefit in meta-analysis or a cluster-randomized trial. Service integration improves coordination within healthcare, but does not address many of the conditions driving the burden outside the clinic. Evidence from India illustrates this gap. In a cluster-randomized trial, household food rations reduced tuberculosis incidence among contacts by about 40%, and the World Health Organization now recommends nutritional support for contacts in food-insecure settings. Prevention therefore needs clinical measures alongside action on undernutrition, housing, income, and access to care.