Impact of early life exposures to geohelminth infections on the development of vaccine immunity, allergic sensitization, and allergic inflammatory diseases in children living in tropical Ecuador: the ECUAVIDA birth cohort study
1 Molecular and Biochemical Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
2 Laboratorio de Investigaciones FEPIS, Gaspar de Villaroel E8-25 y Seymour, Quito, Ecuador
3 Laboratorio de Biología Molecular, Hospital de Los Valles, Avenida Interoceánica Km, 12.5, Cumbayá, Quito, Ecuador
4 Colegio de Ciencias de la Salud, Universidad San Francisco de Quito, Avenida Interoceánica Km, 12.5, Cumbayá, Quito, Ecuador
5 Department of Microbiology and Tropical Medicine, Uniformed Services University of Health Sciences, 4301 Jones Bridge Road, Bethesda, Maryland, 20814, USA
6 Division of Allergy and Clinical Immunology, University of Virginia Health System, 1215 Lee Street, Charlottesville, Virginia, 22908, USA
7 Instituto de Saúde Coletiva, Universidad Federal de Bahia, Rua Basílio da Gama, S/N, Campus Universitário Canala, Salvador, 40.110-040, Brazil
8 Infectious Diseases Epidemiology, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
9 Community Health Sciences, St George's University of London, Cranmer Terrace, London, SW17 ORE, UK
10 Centre for Infectious Diseases, St George's University of London, Cranmer Terrace, London, SW17 ORE, UK
BMC Infectious Diseases 2011, 11:184 doi:10.1186/1471-2334-11-184Published: 29 June 2011
Geohelminth infections are highly prevalent infectious diseases of childhood in many regions of the Tropics, and are associated with significant morbidity especially among pre-school and school-age children. There is growing concern that geohelminth infections, particularly exposures occurring during early life in utero through maternal infections or during infancy, may affect vaccine immunogenicity in populations among whom these infections are endemic. Further, the low prevalence of allergic disease in the rural Tropics has been attributed to the immune modulatory effects of these infections and there is concern that widespread use of anthelmintic treatment in high-risk groups may be associated with an increase in the prevalence of allergic diseases. Because the most widely used vaccines are administered during the first year of life and the antecedents of allergic disease are considered to occur in early childhood, the present study has been designed to investigate the impact of early exposures to geohelminths on the development of protective immunity to vaccines, allergic sensitization, and allergic disease.
A cohort of 2,403 neonates followed up to 8 years of age. Primary exposures are infections with geohelminth parasites during the last trimester of pregnancy and the first 2 years of life. Primary study outcomes are the development of protective immunity to common childhood vaccines (i.e. rotavirus, Haemophilus influenzae type B, Hepatitis B, tetanus toxoid, and oral poliovirus type 3) during the first 5 years of life, the development of eczema by 3 years of age, the development of allergen skin test reactivity at 5 years of age, and the development of asthma at 5 and 8 years of age. Potential immunological mechanisms by which geohelminth infections may affect the study outcomes will be investigated also.
The study will provide information on the potential effects of early exposures to geohelminths (during pregnancy and the first 2 years of life) on the development of vaccine immunity and allergy. The data will inform an ongoing debate of potential effects of geohelminths on child health and will contribute to policy decisions on new interventions designed to improve vaccine immunogenicity and protect against the development of allergic diseases.
Current Controlled Trials ISRCTN41239086.