Mozambique: Health Experts Find Oral Cholera Vaccine Highly Effective Among HIV-Infected Population

A new cholera vaccine is safe and effective in people whose immune systems have been weakened by HIV, researchers announced on Feb. 24, removing an obstacle that prevented the oral vaccine's distribution in HIV-ravaged sub-Saharan Africa. The Bill and Melinda Gates Foundation-funded study was led by researchers from the Seoul-based International Vaccine Institute, the World Health Organization and elsewhere.

Cholera kills an estimated 120,000 people a year, primarily in developing countries. Seventy percent of the world's cholera cases are reported in sub-Saharan Africa. The bacterium, spread mainly through contaminated water or food, attacks the intestine, causing severe diarrhea and dehydration.

From December 2003 to January 2004, researchers conducted a mass cholera vaccination in Beira, Mozambique. About 50,000 Beira residents received two doses of the oral vaccine, rBS-WC, given in successive weeks. Though similar campaigns carried out in Bangladesh and Peru have shown promise, the Mozambique trial was the first targeting a population with high HIV prevalence.

Researchers determined that rBS-WC provides 80-90 percent protection from cholera for six months and 50 percent protection for three years, the researchers reported. Previous needle-administered cholera vaccines provided about 50 percent protection for just two months, they said.

"It is remarkable that such a high level of protection was observed in Beira, a population where 30 percent of adults are living with HIV/AIDS," said IVI Director John Clemens.

"This study's results will be crucial as a prelude to introducing cholera vaccine into the public health programs not only of Mozambique, but elsewhere in Africa where cholera is a significant problem," said Francisco F. Songane, Mozambique's former health minister and coauthor of the study.

The full report, "Effectiveness of Mass Oral Cholera Vaccination in Beira, Mozambique," was published in the New England Journal of Medicine (2005;352(8):757-767).

Back to other news for March 2, 2005