Chickenpox in childhood is associated with decreased atopic disorders, IgE, allergic sensitization, and leukocyte subsets

Background: Wild-type varicella zoster infection (WTVZV) up to 8yr of age has been shown to protect against atopic dermatitis (AD) and asthma. We sought to determine whether WTVZV in childhood protects against atopic disorders, allergic sensitization or decreases serum ImmunoglobulinE (IgE) levels. Methods: We conducted a retrospective, practice-based study of outpatient pediatric practices in NY. One hundred children with WTVZV up to 8yr of age and 323 children who received varicella vaccine (VV) were randomly selected. Results: WTVZV up to 8yr of age is associated with decreased odds of subsequent asthma (exact logistic regression; OR=0.12, 95% CI=0.03-0.57, p=0.003), allergic rhinoconjunctivitis (OR=0.16, 95% CI=0.05-0.49, p=0.0003), and AD (OR=0.57, 95% CI=0.33-0.96, p=0.02), but not food allergies (p=0.78); decreased total serum IgE levels [mixed linear model, LSM (95% CI): 129.09 (33.22-501.63) vs. 334.21 (102.38-1091.04) IU/ml; p=0.02] remained significant at all time intervals after WTVZV (<5, 5-10, and >10) compared with VV (p=0.003-0.03). WTVZV was associated with decreased allergic sensitization (logistic regression, OR=0.11, 95% CI=0.03-0.38, p=0.0004). WTVZV is also associated with persistently decreased numbers of peripheral blood lymphocytes (p<0.0001) for up to 12yr (p=0.0003-0.047), monocytes (p=0.002) for up to 16yr (p<0.001) and basophils at ages 4-6, 10-12, and 14-16 (p<0.03). Conclusion: WTVZV up to 8yr of age protects against atopic disorders, which is likely mediated by suppression of IgE production and allergic sensitization, as well as altered leukocyte distributions.