Mass vaccination could slow cholera
Immunizations in response to outbreaks would limit deaths, study finds
By Nathan Seppa
Vaccinating large numbers of people against cholera at the first signs of an outbreak could save hundreds or even thousands of lives, a new analysis of past epidemics in Zimbabwe, Zanzibar and India shows. Another study indicates that such immediate vaccination in Vietnam may have limited an outbreak there. Both studies appear in the January PLoS Neglected Tropical Diseases.
Although easily administered oral vaccines exist, public health officials typically don’t vaccinate against cholera in the throes of an outbreak because medical workers have their hands full rehydrating patients who have come down with the diarrheal disease. Besides, cholera historically moved on to new areas in a matter of months, well before a vaccine campaign could have an effect. But the Vibrio cholerae bacterium that causes the disease has morphed in recent years, now causing infections that can linger and extend a disease outbreak.
“Historically, the cholera vaccine has been secondary,” says immunologist Edward Ryan of Harvard University and Massachusetts General Hospital in Boston, a cholera expert who wasn’t involved in the new studies. Public health officials have concentrated on detecting cases, rehydrating patients, providing clean water and improving sanitation to stem the spread of cholera, he says.
“The changing features of the pandemic — and data like we’re seeing from these two studies — would suggest it may be time to revisit what role cholera vaccine could play in an outbreak,” Ryan says.