Investigating the association between timing of routine childhood vaccinations and food allergy

In 1 year old children, is there an association between early versus delayed routine childhood immunisations and subsequent challenge proven food allergy at 1 year of age?

Status

Completed

Phases

Unknown

Study type

Observational

Source

ANZCTR

Registry ID

ACTRN12614001193662

Enrollment

4487

Registered

2014-11-13

Start date

2014-10-31

Completion date

2015-03-17

Last updated

2020-01-13

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

None listed

Brief summary

Epidemiological studies of routine vaccinations and allergic disease have had mixed results, with studies showing positive, negative or no association. Very few randomised studies have been performed. Observational studies have the potential to be confounded by reasons for not receiving vaccination which may be associated with allergic disease. To minimise confounding associated with receipt of vaccination, McDonald et al. (JACI 2008;121(3):626-31) investigated the effect of timing of vaccination on asthma, finding that risk of asthma was reduced when the first dose of DTP was delayed by greater than one month. The HealthNuts cohort was initiated in 2007 to study environmental and genetic determinates of food allergy. This population provides an opportunity to test the association between vaccination timing and food allergy using the gold standard outcome of oral food challenges. We hypothesise that there may be an association between delay in the first dose of pertussis-containing vaccine and protection from food allergy at one year of age. Methods: Enrolment, examination and food-allergy testing have been performed as part of the HealthNuts study. Briefly, 5276 parents agreed to enroll their children in the cohort and 5120 had a skin prick test performed at 1 year of age. 1089 children had a positive skin prick test and were invited for an oral food challenge within the following months, of which 928 children completed, along with 197 skin-prick negative control children. Parents also completed an extensive survey of symptoms of allergic disease, family history of allergic disease, demography, environmental factors, and other risk factors for allergic disease. Data on vaccination doses and timing up to 18 months of age will be obtained for children of the HealthNuts cohort from the Australian Childhood Immunisation Register. Statistical analyses will be performed as described.

Interventions

Timing of immunisations delivered at routine immunisation contacts. Data is being collected from the Australian Childhood Immunisation Register which record all childhood vaccination contacts. Date of all childhood immunisations received in the first 18 months of life will be obtained from this register.

Eligibility

Sex/Gender

All

Age

1 Years to 1 Years

Healthy volunteers

Yes

Inclusion criteria

Previously enrolled in the HealthNuts cohort, a large population based study of childhood food allergy in Melbourne, Australia. Briefly, healthy one-year old children were recruited at immunisation contacts and invited to participate.

Exclusion criteria

Refused consent to access Australian Childhood Immunisation Register data

Outcome results