Abstract
Indigenous children in the Northern Territory experience a disproportionately high burden of respiratory infectious diseases associated with conditions favouring microbial transmission and endemic carriage of respiratory pathogens. The lack of a substantive impact in the prevalence of respiratory diseases over the last two decades highlights the ongoing need for improvements in health equity for Indigenous Australians.This thesis investigates the impact of maternal pneumococcal vaccination against, and the influence of maternal/infant vitamin D insufficiency on, the risk of infant respiratory infections. Novel vaccination and supplementation strategies have the potential to be translated into practice.
Principal findings:
1. In a randomised controlled trial of maternal pneumococcal vaccination for the prevention of infant middle ear disease, receiving the 23-valent pneumococcal polysaccharide vaccine in pregnancy:
a. Stimulated a strong maternal vaccine serotype-specific antibody response in both blood and breast milk.
b. Had a non-significant impact on overall infant ear disease and/or nasopharyngeal carriage of vaccine serotypes.
c. Reduced the prevalence of ear disease associated with concurrent carriage of vaccine serotypes (a more specific outcome).
d. Had a non-significant impact on the incidence of infant acute lower respiratory infection (ALRI) hospitalisations.
2. In a prospective cohort of Indigenous mothers and their infants, cord blood vitamin D insufficiency was common at birth and cord blood concentrations were lower among infants subsequently hospitalised with an ALRI compared to infants who were not.
3. In a cross-section of hospitalised Indigenous and non-Indigenous children, vitamin D insufficiency was unexpectedly less common among those with ALRI diagnoses compared to non-ALRI diagnoses (predominantly gastroenteritis). While the data presented in this thesis need to be interpreted with caution due to small sample sizes and limited significance, the findings suggest that maternal pneumococcal vaccination or vitamin D supplementation may have potential as interventions for the prevention of infant respiratory infections. These data lay a strong foundation for the cohort studies or clinical trials necessary to allow informed decisions regarding the future use of these strategies in routine practice.
| Date of Award | Dec 2014 |
|---|---|
| Original language | English |
| Supervisor | Ross Andrews (Supervisor), Anne Chang (Supervisor), Heidi Smith-Vaughan (Supervisor) & Robyn Marsh (Supervisor) |