Vietnam Develops World’s Best Cholera Vaccine

6-04-09, 10:01 am

Vietnam’s Vaccine and Biomedical Product Company No. 1 (VaBiotech) has developed a new cholera vaccine that is superior to others currently in use. “The new vaccine offers 90 to 100 percent protection after two oral doses in comparison with 60 to 70 percent with the current vaccine,” said Dr. Nguyen Tran Hien, Director of Vietnam’s National Institute of Hygiene and Epidemiology.

Registered under the trademark MORACVAX, it produces a strong immune system response in children, who are most susceptible to cholera, as well as adults. Killed Vibrio cholerae, the bacterium that causes cholera, serves as the vaccine’s antigen. This is safer than using a live antigen, which can cause severe adverse effects.

Besides safety, cost is a major concern with vaccines, particularly in developing countries where cholera poses a serious health threat. At US$1.25 per dose, MORACVAX is the world’s first cholera vaccine that is inexpensive enough for widespread use in the developing world. Sweden is the only other country that produces a vaccine with an equally high success rate, but it costs US$10.00 to $30.00 per dose, and is used primarily by travelers from developed countries.

Cholera is a bacterial infection of the intestinal tract that results in severe diarrhea followed by death from dehydration. One of the swiftest killers known to medicine, patients can go into shock and die in as little as three hours unless treated immediately with oral rehydration therapy. Cholera is usually transmitted through ingestion of water contaminated by fecal matter harboring cholera bacteria.

The disease is thought to have originated in Asia, with the earliest recorded epidemic occurring in India in 1563. In the 19th century, cholera killed millions as it spread throughout the world in a series of six pandemics, the last of which ended in 1923. The world is now in the midst of a seventh cholera pandemic that began in Indonesia in 1961. This pandemic, largely unknown to the Western public, brought new strains of cholera to Bangladesh, India, the former USSR, North Africa, Italy, Japan, Mexico, South America, and the South Pacific. Recent years have seen outbreaks in Iraq and Vietnam, but the majority of new cases (approximately 130,000 infections in 2008-09) have been reported in sub-Saharan Africa, particularly in the DR Congo, Angola, Mozambique and Zimbabwe. It is estimated that 100,000 to 200,000 people will die from cholera every year.

Vietnam has long been at the forefront of cholera prevention through public vaccination programs, challenging the practice, promoted for years by aid organizations, of deemphasizing vaccinations due to high costs, low success rates, and safety concerns. The routine practice was to provide stockpiles of oral rehydration solution and chlorine tablets to at-risk populations while stressing development of clean water supplies.

It was in the mid-1980s that Vietnam began working on its first killed, oral cholera vaccine for use in its public health program. The resulting vaccine had a 66 percent success rate, a good safety record, and a production cost as low as 20-cents per dose. Since 1997, over 9 million doses of this first-generation vaccine have been used in Vietnam.

In 2001, due to cholera’s persistence and the apparent failures of the established preventive measures, the World Health Organization (WHO) began advocating worldwide use of oral vaccines. In response to the call, Vietnam began working with WHO and the International Vaccine Institute – the world’s only international organization devoted exclusively to the research and development of new vaccines for developing countries – to create a new version of the Vietnamese vaccine that would meet WHO regulations for worldwide distribution. MORACVAX is the result of this project.

Last February, the vaccine was licensed for production in India and is undergoing trials. In May, VaBiotech produced the first batch of MORACVAX for distribution in Vietnam. The company is capable of manufacturing 10 million doses per year. MORACVAX and the Vietnamese biotech industry are poised to play a decisive role in ending the seventh cholera pandemic.