Egg Allergy Prevalence Before and After Early Egg Introduction Guidelines

Key Takeaways

• The later cohort was associated with lower adjusted egg allergy prevalence than the earlier cohort.
• The observed reduction was larger among infants with early eczema.
• The comparison used two population-based Melbourne samples recruited and assessed with the same methods.

In Melbourne infants assessed after an infant feeding guideline update, adjusted egg allergy prevalence was 7.6% based on findings published in JAMA Pediatrics. The comparison examined population-based cohorts assembled before and after Australian guidance favored earlier egg introduction. Researchers measured egg allergy rather than relying on parent report alone, and the later cohort had a lower adjusted prevalence than the earlier cohort from the same city.

This cross-sectional study included Australian infants aged 11 to 15 months from two population-based Melbourne samples recruited at routine 12-month immunization visits. Investigators used identical recruitment and assessment methods before the guideline update, from 2007 to 2011, and afterward, from 2018 to 2019. The cohorts included 5276 infants before the update and 1933 after, with 7209 of 9500 eligible infants included overall. Response rates were 76% in both cohorts, and median age at assessment was similar at about 12.4 to 12.5 months. Egg allergy ascertainment began with skin prick testing, and infants with positive results then underwent oral food challenges, providing a consistent basis for prevalence estimates across both periods.

To address shifts in background risk and missingness, the investigators used direct regression standardization under the earlier cohort's risk-factor distribution and multiple imputation. In the overall analysis, adjusted egg allergy prevalence decreased from 9.2% in 2007-2011 to 7.6% in 2018-2019, yielding an adjusted absolute difference of -1.6 percentage points. The 95% CI for that overall difference was -3.3 to -0.005. In prespecified analyses of infants with early eczema, prevalence decreased from 34.6% to 21.9%, with an adjusted absolute difference of -12.7 percentage points. The 95% CI for the early eczema subgroup difference was -20.0 to -5.4, representing the largest reported reduction.

The authors described the findings as population-level evidence of lower egg allergy prevalence after updated infant feeding guidance favored earlier egg introduction. Median age at egg introduction decreased from 8 months in 2007-2011 to 6 months in 2018-2019, which aligned with the period comparison. Data were analyzed between March 2025 and March 2026, and prespecified subgroup analyses also stratified infants by parent country of birth. Because the design was cross-sectional, the comparison supports an association with the guideline era rather than proof that the guideline change caused the difference. The later Melbourne sample had a lower measured prevalence of egg allergy.