Hundreds of thousands more people world-wide suffer from tuberculosis than originally thought, and more now die from the infectious airborne disease than from HIV/AIDS, according to new data released Wednesday by the World Health Organization.

The WHO said that TB killed 1.5 million people in 2014, making it a larger cause of death than HIV/AIDS, which was responsible for 1.2 million deaths in the same year. Each of those totals includes 390,000 people who had both infections, and died of TB.

That...