London, July 23 : A currently available and yet unused typhoid vaccine has been found effective in protecting young children in India, according to researchers.

The research team from National Institute of Cholera and Enteric Diseases (NICED) in Kolkata, India and International Vaccine Institute (IVI), Korea showed that vaccine Vi polysaccharide is ideally suited to use in developing countries and can offer protection to almost 80pct of the children.

Multidrug-resistant Salmonella typhi has spread to many parts of the world, limiting the ability to treat typhoid fever with available antibiotics. Typhoid is both a waterborne and food-borne gastrointestinal infection.

The researchers revealed that despite a recommendation by the World Health Organization for use of Vi vaccines in developing countries, its use has been limited, partly because of doubts about Vi''s ability to protect pre-school age children.

This age group is at exceptionally high risk in the poorest settings. There are also doubts about Vi''s ability to confer "herd protection," or protection of unvaccinated residents living in highly vaccinated areas.

During the study, researchers looked at 80 geographic clusters of an urban Kolkata slum.

They were given either Vi or a control vaccine. Over two years of follow-up, the Vi group was shown to have 61 percent fewer episodes of typhoid than the control group.

The study showed that delivering the low-cost Vi typhoid vaccine is logistically and programmatically possible.

Protection of vaccinated children under five years of age by Vi was even higher with 80pct.

"The protection for children under the age of five years is important because this age group has been shown to be at high risk for typhoid fever in many areas where the disease is endemic," said Dr. John Clemens, Director-General of the IVI and an international expert in vaccine evaluation.

Since the coverage of residents of the Vi clusters was about 60percent, this observation indicates that Vi vaccine prevented as many cases of typhoid in the total population as a vaccine that was nearly 100 percent protective in vaccinated persons.

The study appears in New England Journal of Medicine. (ANI)