AbstractPregnant women and young infants have a higher risk of acquiring serious infections of the lower respiratory tract than the general population, including infections caused by influenza, pertussis and pneumococcus. Inactivated influenza vaccine (IIV) and pertussis-containing vaccines are recommended in pregnancy to combat this risk. This thesis aimed to assess the uptake and safety of vaccines in pregnancy, which is recognised as an international priority.
In a cohort of 78,382 births in the Northern Territory (NT) of Australia, in a pre-maternal vaccination era, Aboriginal mothers were 1.7-2.9 times more likely to experience an adverse birth outcome, and infants were 42.3 and 7.1 times more likely to be hospitalised for influenza and pertussis infections respectively, compared to their non-Aboriginal counterparts.
I analysed IIV uptake in pregnancy, and birth outcomes for a group of remote-living Aboriginal women (697 pregnancies) from the NT between 2003 and 2011. Despite high rates of co-morbidities, risk factors and adverse birth outcomes, only 3% (n=20/697) had received IIV in pregnancy.
My analysis of Australia’s largest maternal vaccination cohort study (n=8827 mother-infant pairs) from 2012-2016, showed no significant difference in the risk of adverse birth outcomes among women who received IIV and pertussis vaccinations in pregnancy compared with unvaccinated pregnant women, regardless of the trimester vaccination occurred. Re-analysis of a small randomised controlled-trial of the 23-valent polysaccharide pneumococcal vaccine in pregnancy among NT Aboriginal women, suggested preterm births in vaccinees were more than twice that of unvaccinated controls. These are salient findings, given that the vaccinated and unvaccinated groups were comparable, and trials of pneumococcal vaccination in pregnancy are progressing.
The key findings identified in this thesis indicate studies using much larger participant numbers are required to further evaluate these results, and to test the risk/benefit of maternal vaccination. This thesis will inform future antenatal vaccine policy and research priorities both nationally and globally.
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|Date of Award||Jun 2019|
|Supervisor||Michael Binks (Supervisor), Sue Kildea (Supervisor) & Thomas Snelling (Supervisor)|