Allergy

Timing of routine infant vaccinations and risk of food allergy and eczema at 1 year of age

Kiraly N, Koplin JJ, Crawford NW, Bannister S, Flanagan KL, Holt PG, Gurrin LC, Lowe AJ, Tang MLK, Wake M, Ponsonby A-L, Dharmage SC, Allen KJ. Allergy 2016; 71(4): 541–549

Susceptibility to allergic disease may be influenced by timing of infant vaccinations

Routine vaccinations may have non-targeted effects on susceptibility of allergic disease, possibly related to age at immunisation. 1A recent Australian study investigated whether timing of acellular pertussis vaccination could affect risk of allergic disease in infants. 1In an article published in Allergy, they report evidence that suggests delayed vaccination may reduce susceptibility to eczema, but not food allergy. 1

At the time the studied cohort was born, the diphtheria-tetanus-acellular pertussis (DTaP) vaccine was administered at 2, 4 and 6 months of age in Australia. 1In this study, Kiraly and colleagues linked data obtained from the Australian Childhood Immunisation Register and from the HealthNuts cohort to investigate whether a delay in the first DTaP vaccination was associated with allergic disease. 1

Vaccination data were available for 4,487 children from the HealthNuts cohort, and 99% of these children had received the first dose of DTaP.1 In the vast majority of cases, DTaP was co-administered with other vaccines, including hepatitis B (99.3%), inactivated polio vaccine (99.6%), Haemophilus influenzae type b (99.3%), 13-valent pneumococcal conjugate vaccine (99.2%) and rotavirus (94.1%). 1

99.3% of the children had received all 3 DTaP doses. 1

2.5% of infants had a ‘delayed’ first dose of DTaP (defined as post-90 days of age, i.e. 1 month late). 1

Sensitisation to common food allergens was established by skin prick tests at 12 months of age, after which positive infants were offered an oral food challenge. 1

Food allergy status was based on: 1

• Skin prick test wheal >2 mm
  
• Post-oral-food-challenge specific IgE of >0.35 kUA/L
  
• And any of the following symptoms within 2 hours of oral food challenge:
  
  • >5 minutes of ≥3 concurrent non-contact urticarial
    
  • Vomiting
    
  • Perioral or periorbital angioedema
    
  • Circulatory or respiratory compromise.

Secondary outcomes included incidence of doctor-reported eczema (between 3 and 12 months of age) and parent-reported eczema medication use; wheeze; and hospitalisation for bronchiolitis (during the first 12 months of life). 1

Food allergy and sensitisation

The authors found food allergy at 12 months of age was not significantly associated with delayed DTaP vaccination (p=0.49). 1

However, although on the whole there was no effect of delayed vaccination on atopic sensitisation, the authors reported evidence of gender-specific effects. 1

Delayed vaccination resulted in significantly less atopic sensitisation in females (p=0.06), but not in males (p=0.99). 1

Secondary outcomes

Children with delayed DTaP vaccination were less likely to have eczema (p=0.04). 1

Alongside a decreased likelihood of eczema, the authors also reported reductions in the use of eczema medication in children with delayed DTaP vaccination (p=0.01). 1

No significant association was found between wheeze and bronchiolitis and timing of DTaP vaccination. 1

Conclusions

The authors acknowledged that due to the co-administration of other vaccinations it was not possible to establish which vaccination was responsible for the observed effect on the risk of eczema.1 Furthermore, only a small proportion (2.5%) of the study population had delayed vaccination, which reduced the statistical power of comparisons. 1

The authors concluded that these results suggest that susceptibility to allergic disease may be affected by the timing of routine infant vaccinations, and these findings warrant further study. 1

Report on: Timing of routine infant vaccinations and risk of food allergy and eczema at one year of age. Kiraly N, Koplin JJ, Crawford NW, Bannister S, Flanagan KL, Holt PG, Gurrin LC, Lowe AJ, Tang MLK, Wake M, Ponsonby A-L, Dharmage SC, Allen KJ. Allergy 2016; 71(4): 541–549.

Reference list

1. Kiraly N, Koplin JJ, Crawford NW, Bannister S, Flanagan KL, Holt PG, et al. Timing of routine infant vaccinations and risk of food allergy and eczema at one year of age. Allergy 2016; 71(4): 541–549.