Pertussis immunisation in infancy and atopic outcomes: A protocol for a population-based cohort study using linked administrative data

Introduction The burden of IgE-mediated food allergy in Australian born children is reported to be among the highest globally. This illness shares risk factors and frequently coexists with asthma, one of the most common noncommunicable diseases of childhood. Findings from a case-control study suggest that compared to immunisation with acellular pertussis vaccine, early priming of infants with whole-cell pertussis vaccine may be associated with a lower risk of subsequent IgE-mediated food allergy. If whole-cell vaccination is protective of food allergy and other atopic diseases, especially if protective against childhood asthma, the population-level effects could justify its preferential recommendation. However, the potential beneficial effects of whole-cell pertussis vaccination for the prevention of atopic diseases at a population-scale are yet to be investigated. Methods and analysis Analyses of population-based record linkage data will be undertaken to compare the rates of admissions to hospital for asthma in children aged between 5 and 15 years old, who were born in Western Australia (WA) or New South Wales (NSW) between 1997 and 1999 (329,831) when pertussis immunisation in Australia transitioned from whole-cell to acellular only schedules. In the primary analysis we will estimate hazard ratios and 95% confidence intervals for the time-to-first-event (hospital admissions as above) using Cox proportional hazard models in recipients of a first dose of whole-cell versus acellular pertussis-containing vaccine before 112 days old (~4 months of age). Similarly, we will also fit time-to-recurrent events analyses using Andersen-Gill models, and robust variance estimates to account for potential within-child dependence. Hospitalisations for all-cause anaphylaxis, food anaphylaxis, venom, all-cause urticaria and atopic dermatitis will also be examined in children who received at least one dose of pertussis-containing vaccine by the time of the cohort entry, using analogous statistical methods. Presentations to the emergency departments will be assessed separately using the same statistical approach.

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Community-Based Adverse Food Reactions and Anaphylaxis in Children with IgE-Mediated Food Allergy at Age 6 Years: A Population-Based Study

The Journal of Allergy and Clinical Immunology In Practice ◽

10.1016/j.jaip.2020.07.008 ◽

2020 ◽

Vol 8 (10) ◽

pp. 3515-3524 ◽

Cited By ~ 1

Author(s):

Yichao Wang ◽

Rachel L. Peters ◽

Kirsten P. Perrett ◽

Vicki L. McWilliam ◽

Mimi L.K. Tang ◽

...

Keyword(s):

Food Allergy ◽

Population Based ◽

Community Based ◽

Population Based Study ◽

Ige Mediated

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Protocol for Pertussis Immunisation and Food Allergy (PIFA): a case–control study of the association between pertussis vaccination in infancy and the risk of IgE-mediated food allergy among Australian children

BMJ Open ◽

10.1136/bmjopen-2017-020232 ◽

2018 ◽

Vol 8 (1) ◽

pp. e020232 ◽

Cited By ~ 1

Author(s):

Marie J Estcourt ◽

Julie A Marsh ◽

Dianne E Campbell ◽

Michael S Gold ◽

Katrina J Allen ◽

...

Keyword(s):

Food Allergy ◽

Pertussis Vaccine ◽

Case Control Study ◽

Conditional Logistic Regression ◽

Case Control ◽

Scientific Presentation ◽

Children's Hospital ◽

Children’S Hospital ◽

Ige Mediated ◽

Control Study

IntroductionAtopic diseases, including food allergy, have become a predominant cause of chronic illness among children in developed countries. In Australia, a rise in hospitalisations among infants coded as anaphylaxis to foods coincided with the replacement of whole-cell pertussis (wP) vaccine with subunit acellular pertussis (aP) vaccine on the national immunisation schedule in the late 1990s. Atopy is characterised by a tendency to mount T helper type 2 (Th2) responses to otherwise innocuous environmental antigens. Compared with infants who receive aP as their first pertussis vaccine, those who receive wP appear less likely to mount Th2 immune responses to either vaccine or extraneous antigens. We therefore speculate that removal of wP from the vaccine schedule contributed to the observed rise in IgE-mediated food allergy among Australian infants.Methods and analysisThis is a retrospective individually matched case–control study among a cohort of Australian children born from 1997 to 1999, the period of transition from wP to aP vaccines; we include in the cohort children listed on Australia’s comprehensive population-based immunisation register as having received a first dose of either pertussis vaccine by 16 weeks old. 500 cohort children diagnosed as having IgE-mediated food allergy at specialist allergy clinics will be included as cases. Controls matched to each case by date and jurisdiction of birth and regional socioeconomic index will be sampled from the immunisation register. Conditional logistic regression will be used to estimate OR (±95% CI) of receipt of wP (vs aP) as the first vaccine dose among cases compared with controls.Ethics and disseminationThe study is approved by all relevant human research ethics committees: Western Australia Child and Adolescent Health Services (2015052EP), Women’s and Children’s Hospital (HREC/15/WCHN/162), Royal Children’s Hospital (35230A) and Sydney Children’s Hospital Network (HREC/15/SCHN/405). Outcomes will be disseminated through publication and scientific presentation.Trial registration numberNCT02490007.

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