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Keywords:

  • allergy;
  • asthma;
  • atopy;
  • BCG ;
  • vitamin A supplementation

Abstract

Background

Recent evidence suggests that immunogenic interventions such as vaccines and micronutrients may affect atopic sensitization and atopic disease. We aimed to determine whether neonatal BCG vaccination, vitamin A supplementation and other vaccinations affect atopy in childhood.

Methods

In Guinea–Bissau, low-birthweight infants were randomized to early (intervention) or delayed (usual policy) BCG. A subgroup was also randomly assigned vitamin A supplementation or placebo in a two-by-two factorial design. Participants were followed up at age 3–9 years. The main outcome was atopy defined as skin prick test reaction ≥3 mm. Secondary outcomes were symptoms of eczema, asthma and food allergy.

Results

Two hundred eighty-one children had valid skin prick tests performed, and 14% (39/281) were atopic. There was no significant difference in atopy between the early and delayed BCG groups (OR, 0.71; 95% CI, 0.34–1.47). Atopy was significantly reduced in children who had responded to BCG with a scar (OR, 0.42; 0.19–0.94). Vitamin A supplementation was associated with increased atopy (OR, 2.88; 1.26–6.58), especially in those who received simultaneous BCG (5.99; 1.99–18.1, = 0.09 for interaction between vitamin A supplementation and BCG). Early vs delayed BCG was not associated with symptoms of atopic disease, but vitamin A supplementation increased odds of wheeze within the past 12 months (OR, 2.45; 1.20–4.96).

Conclusions

There were no statistically significant effects of early vs delayed BCG on atopy or symptoms of atopic disease. Having a BCG scar was associated with reduced atopy, whereas neonatal vitamin A supplementation was associated with increased atopy.

Study Registration

Clinicaltrials.gov NCT 01420705.