Extensive test shows cholera vaccine works

Science News, Dec 4, 2004

A reliable, long-lasting vaccine against cholera has eluded medical science. The best vaccine available during the 20th century was scrapped in the 1970s because it offered only weak protection. In the 1980s, Swedish researchers developed an oral vaccine, and trials done since then have indicated that it offers better protection than the abandoned vaccine did.

In its first massive test, the oral vaccine has proved effective in preventing the life-threatening diarrhea that cholera causes, researchers working in Mozambique report. These new data establish the vaccine's value for public health campaigns against cholera, suggests Jacqueline L. Deen of the International Vaccine Institute in Seoul, South Korea.

Mozambique accounts for 18 percent of all cholera cases worldwide, Deen notes. Many epidemics strike the country's marshy port city of Beira, which has poor water-supply and municipal-waste-disposal systems. Cholera spreads via tainted drinking water.

At the start of a cholera outbreak during the rainy season spanning late 2003 and early 2004, clinics in Beira dispensed two doses of the oral cholera vaccine, a month apart, to each of nearly 50,000 people. In a follow-up study, Deen and her colleagues determined that the vaccine was up to 81 percent effective in preventing cholera. In children under age 5, the vaccine was particularly protective. That's a heartening result, since it's primarily young children that cholera kills, Deen says.--N.S.