A New Weapon To Fight Dengue

When Sanofi hit a snag, Takeda doubled down on a vaccine coming to market next year

- Kanoko Matsuyama

After decades of delays, the first vaccine for dengue fever was introduced seven years ago. But that formula, from Sanofi, was soon found to be suitable only for people who'd previously been infected with the disease, spurring Japan's Takeda Pharmaceutical Co. to redouble its work on an alternative. That effort is finally paying off, with its version expected to hit the market in early 2023.

Dengue infections have jumped eightfold over the past two decades, to almost 400 million a year, according to researchers at the University of Oxford. About half the world's population already lives in areas threatened by dengue, and scientists warn that climate change will likely hasten the spread of mosquitoes that carry the virus. Since 2013 the US has seen outbreaks in Florida, Hawaii and Texas. Europe saw local transmission in France and Croatia in 2010, and a 2012 outbreak on Portugal’s Madeira island resulted in more than 2,000 cases.

Although most dengue cases are mild, typically causing flu-like symptoms, some infected people suffer a sudden onset of fever, headache, rashes and muscle pain so severe that the disease is also called “break-bone fever.” A half-million dengue patients a year require hospitalization from complications that can result in shock and internal bleeding. About 20,000 die, primarily children.