Shout out to the Bill & Melinda Gates foundation: In 1999, Dr. Clemens approached what is now the Bill & Melinda Gates Foundation, which was just getting organized. “They were literally operating out of a basement then,” he said. “I got a letter from Bill Gates Sr. It was very relaxed, sort of, ‘Here’s $40 million. Would you mind sending me a report once in a while?’ “But without that,” Dr. Clemens continued, “this wouldn’t have seen the light of day.” With that money, Dr. Clemens reformulated Dr. Dang’s vaccine, conducted a successful clinical trial in Calcutta and found an Indian company, Shantha Biotechnics, that could make it to W.H.O. standards. Rolled out in 2009 under the name Shanchol, it came in a vial about the size of a chess rook, needed no buffer and cost less than $2 a dose. Even so, there was little interest, even from the W.H.O. The vaccine lacked the publicity campaign that pharmaceutical companies throw behind commercial products, and “cholera ward care” was saving many lives — when it could be organized. The new vaccine was not used in a cholera outbreak in Zimbabwe in 2009, or initially in Haiti’s explosive outbreak in 2010.Because no pharmaceutical company had an incentive to pay for trials or factories, his invention languished in “the valley of death” — the expensive gap between a product that works in a lab and a factory-made version safe for millions.