March 26, 2022: A convoy of five vans snaked slowly on Friday from the battered Ukrainian capital, Kyiv, toward Chernihiv, in the northeast of the country. On board were generators, clothes, fuel — and medications needed to treat H.I.V.

TB kills 1.5 million people each year. Lockdowns and supply-chain disruptions threaten progress against the disease as well as HIV and malaria.

Tuberculosis struck 10 million people worldwide in 2017, killing 1.6 million of them – a toll greater than that of HIV, malaria, measles and Ebola combined. TB is the leading infectious killer around the globe; nearly 1.8 billion people are carrying the bacterium that causes the disease.

Two antibiotics, taken for a month, can stop a leading killer. But “when it’s for TB, people just sort of shrug.”

The W.H.O. has recommended such a test for H.I.V.-positive patients since 2015. But in poor countries, few qualifying patients are receiving it.