Seroepidemiology of Helicobacter pylori infection in a cohort of children monitored from 6 months to 11 years of age.

A cohort of Swedish children was monitored from 6 months to 11 years of age. Immunoglobulin G (IgG) and IgA antibodies to Helicobacter pylori were measured in 1,857 serum samples, drawn at the ages of 6, 8, 10, 18 months and 2, 4, and 11 years. Of the 294 children, 40 (13.6%) were found to have been infected at some time. However, at 11 years of age, only 6 of 201 (3%) children were seropositive. The highest seroprevalence of positive results, 10%, was found at 2 years of age, and the highest incidence of 13.3% could be calculated for the period between 18 months and 2 years of age. There were no confirmed additional cases for children between 4 and 11 years of age. Infection with H. pylori thus occurs at an early age in a developed country (as well as in developing countries), and spontaneous clearance seems to be common.