Amid Ebola, Progress on Another Epidemic

Dengue fever doesn’t get the attention it deserves, to the point that the World Health Organization considers it one of 17 "neglected tropical diseases." These illnesses mainly hit the world’s poorest pockets, which is largely why they’re ignored. So it’s a big deal that the French drug company Sanofi has developed a fairly effective dengue vaccine.

The WHO estimates that 50 to 100 million people spread across 100 countries are infected with dengue each year, "putting almost half of the world’s population at risk." Dengue is often overshadowed by malaria, which affects two-to-four times as many people annually and is more frequently fatal. Although malaria’s deadliness has been subdued, a "global resurgence of epidemic dengue fever" is on a 25-year run, says the WHO. Dengue is the world’s fastest-growing mosquito-borne disease and a lead cause of hospitalization in Southeast Asia and Latin America now. The rate of cases has jumped 30-fold in the last 50 years.

It’s also extremely painful. Besides fever, symptoms include headache, nausea, bleeding, and pain in the joints, muscles, and even bones — hence its rather apt nickname, "breakbone fever." And thanks to migration, urbanization, and climate change, it’s now spreading to more temperate and developed regions.

The vaccine, which the company hopes to start selling by the end of next year, should help stunt that trend. The vaccine’s last trial found that it lowered dengue cases by 61 percent and cut dengue hospitalizations 80 percent. Dengue victims tend to grow sicker– and face greater risks of dying — the more times they’re exposed to the virus. The vaccine most effectively prevented pre-exposed patients from catching another strain.

West Africa’s Ebola outbreak reminds the world that deadly infectious disease can quickly spread far and wide. And with more than 1,900 dead and the WHO warning that as many as 20,000 may be infected before the epidemic subsides, the dengue vaccine is a rare bright spot.