An Old Foe Dethrones Covid-19 as the World’s Leading Infectious Killer

One of the deadliest diseases in the world is back on top. This week, the World Health Organization reported that tuberculosis is once again the global leading cause of death from infectious diseases, reclaiming the mantle from covid-19.

On Tuesday, the WHO released its latest Global Tuberculosis Report, an annual assessment of the bacterial disease’s toll on humanity. According to the report, 8.2 million people were newly diagnosed with TB in 2023—a record high in the history of the WHO’s modern tracking of TB, which first began in 1995. In total, roughly 10.8 million people became sick with TB last year, and there were approximately 1.25 million TB-related deaths.

“The fact that TB still kills and sickens so many people is an outrage, when we have the tools to prevent it, detect it and treat it,” said WHO Director-General Tedros Adhanom Ghebreyesus in a statement. “WHO urges all countries to make good on the concrete commitments they have made to expand the use of those tools, and to end TB.”

TB is caused by Mycobacterium tuberculosis. It spreads between people through the air and typically affects the lungs, though the bacteria can invade other parts of the body. Acute cases of TB usually result in respiratory symptoms like chest pains, chills, and coughing up blood. But the infection can often become latent, not causing illness until years later when the immune system is weakened for another reason. People with HIV are especially vulnerable to TB, since they’re much more likely to develop an acute, life-threatening case.

TB’s death toll in 2023 was enough to supplant that of any other single infectious disease. Covid-19 remains a real public health threat, but recorded deaths have greatly declined since 2022, both in the U.S. and worldwide (according to data collected by the WHO, there were 320,000 covid-19 deaths reported last year). That said, the numbers are a slight improvement over 2022, which saw 1.32 million TB-related deaths. And there have been some other positive trends as of late.

At the same time, there is the added danger of superbug TB. There were an estimated 400,000 people with multidrug-resistant or rifampicin-resistant TB last year, but only about 44% of patients were actually diagnosed and treated. Treatment success for these difficult cases has increased, now reaching 68%. Other data shows that TB has been making a comeback in the U.S. as well.

Overall, the global efforts to control and prevent TB are well behind the targets recommended by the WHO. And research into interventions like improved drugs and vaccines for TB is critically underfunded. So much more will need to be done to curtail this major killer.

“We are confronted with a multitude of formidable challenges: funding shortfalls and catastrophic financial burden on those affected, climate change, conflict, migration and displacement, pandemics, and drug-resistant tuberculosis, a significant driver of antimicrobial resistance,” said Tereza Kasaeva, Director of WHO’s Global Tuberculosis Program in a statement. “It is imperative that we unite across all sectors and stakeholders, to confront these pressing issues and ramp up our efforts.”