PREVENTION OF HELICOBACTER-PYLORI INFECTION

A gastroenterologist, treating a patient with H. pylori, must decide whether the unit of treatment is only the ill individual, or the family, perhaps including close contacts. If it is the family and close contacts, is it all family members and contacts, or are there some ages, relationships, or clinical characteristics that increase the risk of transmission to the patient after successful treatment of their infection? In preventing reinfection, the available data suggest: • - the natural infectious dose has not been determined • - infection may occur from oral or faecal shedding • - children are more infectious than adults • - socio-economic factors are important in any comparison of infection rates • - food and water seem unlikely vehicles in the developed world • - travel in the third world may increase risk of infection • - seropositivity in adults predominantly reflects exposure in childhood • - infection is frequently with more than one strain • - reinfections are not more frequent in families with other members infected • - reinfections are infrequent with strains different from the original strain • - reinfection might be more frequent in developing countries • - no need for all family members to be treated to reduce reinfection rates. In considering vaccine, the available data suggest: • - breast milk IgA can reduce infection rate • - antibodies induced by vaccine may reduce infection in animals • - late benefit of childhood vaccination in developed countries • - probable early benefit of childhood vaccination in developing countries • - vaccination of already infected adults would have cost-benefit. © 1995.