Lower hookworm incidence, prevalence, and intensity of infection in children with a bacillus Calmette-Guerin vaccination scar

Bacillus Calmette-Guerin (BCG), the most common vaccine worldwide, has broa d effects on the immune system. Hookworm infections are a major source of m orbidity. In response to a preliminary report of BCG vaccination protection against nematodes in human immunodeficiency virus-infected adults, data fr om an ongoing prospective study were analyzed to determine the intensity (e ggs per gram of stool), prevalence, and incidence of different helminths in children with and without a BCG vaccination scar. Adjusted prevalence and incidence ratios were estimated by using logistic regression. Children with a BCG vaccination scar were found to have statistically significantly lowe r hookworm prevalence (41%), incidence (37%), and mean egg counts (39%), af ter controlling for age, sex, and socioeconomic factors. There was no BCG a ssociation with incidence, prevalence, or intensity of infection with Schis tosoma mansoni, Ascaris lumbricoides, or Trichuris trichiura. Such protecti on would have implications for public health and for research on mechanisms behind human immunological responses to hookworm.