It's been decades since dengue fever killed thousands of US and Japanese troops in World War II—yet we still don't have an effective vaccine against it. That could be about to change, Reuters reports: A Paris company is testing just such a drug among children in Thailand, with results due in September. That would pave the way to selling the vaccine in 2015, fending off 100 million cases a year, including 20,000 deaths.
Spread by mosquitoes, dengue fever has existed since at least the 18th century, when it was detected on three continents. Its spread among troops during World War II turned it into a pandemic, and today it's 30 times as common as it was just 50 years ago. If French firm Sanofi is successful—and "everything they've done so far looks very good," says an expert—it would mark a blow to the US Army, which has been working toward a vaccine with GlaxoSmithKline. The next hurdle would be determining pricing, particularly for the disease's many victims living in poverty. (Read more Dengue Fever stories.)