The U.S. Food and Drug Administration has approved a generic version of the world’s only twice-a-year shot to prevent HIV. This is a big step toward making the extremely effective drug available inexpensively and quickly in 120 low- and middle-income countries. The drug, called lenacapavir, is expected to cost $40 a person each year in these places, the same price as daily preventive pills available now. But the shots are much more convenient than the pills because they’re needed much less frequently. The generic will not be available in the U.S. because there is a brand-name version still protected by a patent.