New typhoid vaccine for young children

Wednesday, April 25th 2001, 12:00 am
By: News On 6

NEW ORLEANS (AP) _ A new vaccine will allow doctors to immunize children younger than 5 against typhoid fever, a disease that affects 16 million people worldwide and kills 600,000 every year.

Current vaccines are not recommended for children under the age of 6.

The new vaccine has fewer side effects and is much more effective than those currently available, doctors at the Institute of Child Health and Human Development report in Thursday's issue of the New England Journal of Medicine.

It protected more than 90 percent of the 5,525 Vietnamese children who received it, compared with an immunization rate of 70 percent for current vaccines, Dr. Feng Ying C. Lin wrote in the study.

The researchers plan to begin trials of the new vaccine in infants late this year.

If their findings are confirmed in babies, Drs. Richard Guerrant and Margaret Kosek of the University of Virginia wrote in an editorial, ``this vaccine will provide another exciting advance in the fight against an increasingly resistant, highly virulent pathogen of poverty.''

``This is exciting. It really is an important advance, especially in what are really diseases now of inadequate water and sanitation,'' Guerrant, a geographic medicine professor, said in an interview. He said, however, that the vaccine can't be considered a substitute for development and improved sanitation.

Doctors believed for a long time that children did not get typhoid, but in the Mekong Delta province of Dong Thap, where the study was done, 413 of every 100,000 children came down with the disease, Lin wrote.

The overall rate throughout Asia is about 500 people per 100,000, co-author Shousun C. Szu said.

The disease is spread by contaminated sewage and by food or drinks handled by someone infected with or carrying the typhoid germ, Salmonella typhi.

Doctors treat only about 400 cases of typhoid each year in the United States, and 70 percent of those people caught the disease during travel in developing nations, according to the U.S. Centers for Disease Control and Prevention.

However, typhoid is very common in India and developing countries in Asia, Africa and Latin America. In many of those countries, the germ is resistant to common antibiotics, forcing doctors to use those in a more expensive group, Szu said.

In Vietnam, about 75 percent of the bacteria are resistant to several antibiotics; the figure is about 80 percent in India, Szu said.

The journal report said four of the 5,525 vaccinated children developed typhoid, compared to 47 out of 5,566 who got shots without the vaccine.

The children who did get typhoid in spite of the vaccine apparently were protected from serious illness: All of those who had to be hospitalized were in the comparison group.

The vaccine used a technique that won two of the researchers the 1996 Lasker and Pasteur award for their work to develop a vaccine against Haemophilus influenza type B, a cause of meningitis.

They linked the bacteria's outer capsule, which slips through young children's undeveloped immune systems, to a protein molecule which the immune system easily recognizes. The vaccine has almost eliminated ``Hib'' as a cause of meningitis in this country.