SEOUL, South Korea--A study supported by the Bill and Melinda Gates Foundation and led by researchers at the International Vaccine Institute in Seoul found a new-generation oral vaccine against cholera to be highly protective against the disease in Mozambique. The study was published in the February 24 issue of the New England Journal of Medicine.
Cholera causes severe, life-threatening diarrhea. In an outbreak of cholera in a refugee camp in Zaire in 1992, more than 10,000 persons died of cholera within one week. To date, this vaccine, called rBS-WC, has been used mainly by Western tourists visiting poor countries. People living in places like Beira, Mozambique, where cholera outbreaks occur every year, have previously never had the chance to be protected by vaccination. Experts say that the study could pave the way towards expanded use of cholera vaccines in poor areas, where they are needed most.
A mass oral cholera vaccination campaign was carried out in Beira from December 2003 to January 2004. This was a collaborative effort between the Mozambique Ministry of Health, Medecins Sans Frontieres, Epicentre, the World Health Organization, and the International Vaccine Institute. More than 100,000 doses of vaccine were donated for the study by SBL Vaccines in Sweden.
Following vaccination, the researchers found that the vaccine provided about 80% protection against all episodes of cholera. The vaccine was protective both for children and adults and appeared was 90% protective against cholera of life-threatening severity.
Dr. John Clemens, Director of the International Vaccine Institute, commented "Killed oral vaccines such as rBS-WC may be our only option for vaccinating against cholera in countries such as Mozambique where HIV infections are common, since these killed vaccines are safe for persons living with HIV. It is remarkable that such a high level of vaccine protection was achieved in Beira, a population where 30% of adults are living with HIV/AIDS."
Cholera is endemic and widely feared in Mozambique, and continues to afflict the population every year despite attempts to improve water supply and sanitation. As a result, there is increasing interest in the use of cholera vaccines. Mozambique´s former Minister of Health and one of the authors of the study, Dr Francisco F. Songane, said "Cholera has become an intractable problem in Mozambique. 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."
Following the positive results from this research and in the wake of the recent tsunami disaster, the Government of Korea has recently pledged to spearhead the creation of a global cholera vaccine stockpile that can be used to aid victims of the tsunami and other disasters that place people at risk for cholera.
The International Vaccine Institute, hosted by the government of Korea, is the world´s only international research organization devoted exclusively to new vaccines for the poor in developing countries. Its research programs are being conducted in 21 developing countries of Asia, Africa, and Latin America.
The mass oral vaccination in Beira, Mozambique
Patients at the Cholera Treatment Center in Beira, Mozambique