This cross-sectional study compared the population prevalence of egg allergy in infants aged 11–15 months in Melbourne, Australia, before (2007–2011, n=5,276) and after (2018–2019, n=1,933) updated allergy prevention guidelines recommending earlier egg introduction, using regression standardization to control for known risk factors.
After risk-factor adjustment, egg allergy prevalence fell from 9.2% to 7.6% (adjusted absolute difference −1.6 percentage points; 95% CI, −3.3 to −0.005). Among infants with early eczema, the drop was far larger: 34.6% to 21.9% (adjusted absolute difference −12.7 percentage points; 95% CI, −20.0 to −5.4).
- Observational cross-sectional design cannot establish causation; residual confounding is possible. - Guideline change and cohort period are collinear, so other time-varying factors cannot be fully excluded. - The overall population effect (−1.6 pp) has a confidence interval that barely excludes zero, making the general-population finding statistically marginal.
These data support current guidelines recommending egg introduction at around 6 months, especially for infants with eczema, who showed the largest absolute benefit. Clinicians should prioritize early egg introduction in eczema-affected infants as a meaningful allergy-prevention strategy.
