And in contrast to other typhoid vaccines, it is virtually free of side effects. More than 90 per cent of the typhoid strains present in the area are resistant to the antibiotics used to treat the disease. The approach involves chemically linking a polysaccharide from the disease- causing bacteria with a protein molecule. Ordinarily, the polysaccharide would slip past the defenses of a child's immature immune system. But adding the protein to the polysaccharide allows the immune system to produce antibodies that inactivate the bacteria.
Antibodies are immune system proteins that recognize a particular substance.
Together with another protein called complement, antibodies begin the first steps in the complex sequences of events by which the immune system destroys disease-causing organisms.