Serum Antibody Responses to Childhood Vaccinations in Children Impacted by Regional Gold Mining in Madre de Dios, Peru

Introduction: Childhood heavy metal exposure is a major environmental health hazard. Some heavy metals (lead, arsenic, and cadmium) are understood to modulate certain immune functions, while the impacts of other metals are less known. In Madre de Dios (MDD), Peru, regional gold mining has increased the input of heavy metals into the environment, particularly mercury, increasing exposure risk to children. The objective of this study is to measure the effect of metal exposures to vaccine response in children. Methods: In a cohort study of children 6 years old and under (n=300) and their parents, we measure metal exposure in hair (mercury) and toenail (mercury, lead, arsenic, cadmium, manganese, selenium, zinc, nickel) biomarkers. Antibodies to six childhood vaccines (H. influenzae, measles, pertussis, tetanus, diphtheria, hepatitis B) are measured in serum using a bead-based multiplex assay. Vaccine history (date of vaccination and dose) and storage by the health post was recorded. Results: Toenails, vaccin...