TB reclaims title of deadliest infectious disease. That's an 'outrage' says WHO

The ancient scourge of tuberculosis for years was the deadliest infectious disease. Then SARS-CoV-2 came along and grabbed the notorious title of #1 killer: In 2020, COVID-19 was responsible for 3.5 million deaths worldwide vs 1.5 million for TB.The 2024 Global Tuberculosis Report, published last week by the World Health Organization, puts TB back in the top slot with 1.25 million deaths in 2023 compared to 320,000 COVID-19 deaths. There's also been an increase of hundreds of thousands of new TB cases in 2023 compared to the year prior.

The 1.25 million TB deaths in 2023 is down from 2022’s number of 1.32 million (which that year was second to the COVID toll). But it's still indefensibly high, say public health leaders.

“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 Tedros Adhanom Ghebreyesus, WHO director-general, in a statement issued on October 29.

According to the report, approximately 8.2 million people were newly diagnosed with TB in 2023 — the highest number since WHO began global TB monitoring in 1995 and a “notable increase” from 7.5 million people newly diagnosed in 2022.

TB sleuths are trying to figure out the reasons behind the increase. Anand Date, global TB branch chief at the Centers for Disease Control and Prevention, says population growth may account for the increase in cases last year -- and that it may take until the 2024 to find out if that is so or if the leap in 2023 reflects an undercount of annual TB totals during the pandemic.

“Disruptions to TB programs during the height of the pandemic led to more people going undiagnosed and untreated for TB. [And] guidance to shelter in place may have also limited the spread of TB, says Yogan Pillay, who heads efforts to improve TB program delivery at the Bill and Melinda Gates Foundation (which is a funder of NPR and this blog).

COVID-19 did trigger a new setback in the effort to control TB. But most of the reasons the infection persists are frustratingly well-known, says Lucica Ditiu, executive director of the Stop TB Partnership. There's too little money for research, treatment. and patient care needs. And there's stigma that can keep the most common victims of TB, impoverished people including migrants and sex workers, from seeking help or being offered treatment.

In addition, health conditions like malnutrition, diabetes and smoking that can exacerbate TB and keep medications from being fully effective, says Luke Davis, a TB and HIV specialist at the Yale School of Public Health. “TB is unusual,” says Davis, in that most people who are exposed to the bacteria won’t progress to infectious TB. Only about 10% do, and they are usually among the world’s poorest people often with poor health to begin with, which exacerbates their condition.”

So what's the solution?

And that brings us to the Tedros point. The world knows how to vanquish TB — but is not doing a good job.

Money reigns as perhaps the biggest obstacle to conquering tuberculosis. A spokesperson for WHO tells NPR: “Compared with global funding targets for TB set at the 2023 U.N. high-level meeting on TB, there are large funding shortfalls for TB research as well as prevention, detection and treatment services. To close these gaps, more funding is needed from both domestic sources in the countries most impacted by TB and from international donors.”

Global funding for TB prevention and care decreased in 2023 from $6 billion in the three previous years to $5.7 billion and remains far below the yearly target of $22 billion, according to WHO.

What would more money bring? WHO cites expanded rapid diagnostic testing as critical. Then treatment can start sooner. And people wouldn’t have to travel long distances to a clinic then wait for days for the results.

Increased funding would also help reimburse families for lost wages and food and travel expenses incurred as they go for treatment. Those costs keep some patients and their families from seeking care.

The WHO report and other investigations also say that countries burdened by TB also have to step up and spend more money on prevention, diagnosis and treatment. A report by MSF/Doctors Without Borders published last month, for example, found that, only 5 out of 14 countries have adapted their guidelines — based on WHO recommendations -- to initiate TB treatment in children when symptoms strongly indicate TB disease, even if bacteriological tests are negative.

And increased funding would speed up the pace of research says the CDC’s Date. Funding for TB research has stagnated at around $1 billion per year, constraining progress, according to WHO. The target at the U.N. meeting: $5 billion per year by 2027. “The world also has the most promising R&D pipeline of new TB tools in decades,” says Pillay. “What’s needed now is greater investment to deliver on the promise of that pipeline and ensure patients and those at risk of TB have affordable and equitable access to these tools when they are available.”

Vaccines in the works

Pillay says there are more than a dozen TB vaccine candidates in clinical trials, including one whose late stage (stage 3) clinical trial is sponsored by the Gates Medical Research Institute. The trial began recruiting patients last March. That vaccine candidate is called M72/AS01E and if proven effective would be the first new TB vaccine in 100 years. The lone TB vaccine available now is not predictably effective in adults, and can cause a false positive result on TB skin tests.

But even an effective vaccine won’t do that much good if there aren’t funds to purchase it for countries impacted by TB. Janeen Madan Keller, deputy director of the Global Health Policy Program at the Center for Global Development, based in Washington, D.C., says that while Gavi, The Vaccine Alliance, pays for [a variety of] vaccines in some of the poorest countries such as Afghanistan, Burundi and the Democratic Republic of the Congo, some countries with high rates of TB are middle income countries, like Indonesia, and no longer eligible for support. Ahead of a TB vaccine’s approval, says Keller, there needs to be a better match of policy and funding.

“Often it seems that when we find a way to help vanquish TB,” says Lucica Ditiu, “we also find another barrier.”

Fran Kritz is a health policy reporter based in Washington, D.C., and a regular contributor to NPR. She also reports for the Washington Post and Verywell Health. Find her on X: @fkritz