Rosenlund H, Bergström A, Alm JS, et al; PARSIFAL Study Group. Pediatrics. 2009;123(3):771–778
PURPOSE OF THE STUDY. To determine the role of measles vaccination and infection in the outcome of allergic disease and atopic sensitization.
STUDY POPULATION. A total of 14 893 children 5 to 13 years of age were included from the cross-sectional, multicenter, Prevention of Allergy–Risk Factors for Sensitization in Children Related to Farming and Anthroposophic Lifestyle (PARSIFAL) study, conducted in 5 European countries.
METHODS. Four groups of children were compared, those in farming communities, those attending Steiner schools (which are known for avoidance of immunizations), and nonfarming and non-Steiner reference groups. By using parental questionnaires based on previously validated questionnaires (including the International Study of Asthma and Allergies in Children), 14 893 children (69% response rate) were evaluated for environmental exposures, history of vaccinations and infections, lifestyle factors, and symptoms and diagnoses of allergic diseases. Atopic sensitization was defined as ≥1 allergen-specific immunoglobulin E level of ≥0.35 kU/L against inhalant allergens and/or foods. A sample of children with complete information on measles vaccination and infection was invited to undergo an additional blood test, and 4049 children (83% response rate) did so, with parental consent.
RESULTS. In reviewing the entire group of children, atopic sensitization was inversely related to measles infection and vaccination. After exclusion of children who confirmed symptoms of wheezing and/or eczema in the first year of life, an inverse relationship was noted between measles infection but not vaccination and “any allergic symptom” or “any diagnosis of allergy by a physician.”
CONCLUSIONS. The authors concluded that measles infection may be protective against allergic conditions in children.
REVIEWER COMMENTS. The literature is inconsistent on the relationship between measles infection and allergic disease or atopic sensitization. The predominant confounder in these studies is determining and controlling for whether the exposure precedes the disease, which is a problem in this study as well. The strengths of the study are its size and international design, with a high prevalence of measles infection. However, there was a low prevalence of allergic disease and sensitization in the reference group. The authors also cannot exclude other vaccinations included in the measles-mumps-rubella vaccine or other aspects of the anthroposophic lifestyle that may affect the observed relationship. Additional prospective cohort studies are needed to establish causality.
- Copyright © 2009 by the American Academy of Pediatrics