DOVE in the Time of Cholera

The more things change, the more they stay the same.

Epidemic cholera has been eliminated from Europe and North America, and rehydration therapy and antibiotics have significantly reduced mortality rates in Africa and Asia. Yet International Health Professor David Sack, MD, estimates that Vibrio cholera still infects more than 2.5 million people each year, killing more than 200,000. (The disease causes diarrhea so severe that death by dehydration can result in a matter of hours.)

While inexpensive oral vaccines are available, they have yet to be widely used—a situation Sack hopes to remedy through a new project, Delivering Oral Vaccine Effectively (DOVE), which recently received nearly $5 million in support from the Bill & Melinda Gates Foundation.

Sack helped run the initial field trials for the vaccines, which require two doses, back in the mid-1980s. Despite offering 70 percent protection with no known side effects, adoption has been slow. Some have held out for a live, single-dose vaccine or questioned the utility of vaccines with less than 85 percent protection. To Sack, who directs the Enterics Laboratory of the Center for Immunization Research, this represents a clear case of “the ideal being the enemy of the good.”

“Public health benefit is not measured by efficacy,” he says. “Public health benefit is measured by the number of deaths averted.” And with a disease as common as cholera, even 70 percent protection will save many lives.

DOVE will therefore help governments and health agencies deploy the existing vaccines as effectively as possible. With funding from the Gates Foundation and help from organizations like the International Vaccine Institute; the International Center for Diarrhoeal Disease Research, Bangladesh; and WHO, DOVE will document the implementation of pilot programs in places such as Haiti, India, Bangladesh and Africa. The goal is to learn how best to include the new oral vaccines in an integrated strategy for cholera control.