- To determine if maternal vaccination with the 23-valent pneumococcal polysaccharide vaccine (23vPPV), given antepartum or immediately postpartum, can reduce nasopharyngeal carriage of vaccine type pneumococci and prevalence of middle ear disease among Indigenous children at seven months of age.
To determine if maternal immunisation with 23 valent pneumococcal polysaccharide vaccine (23vPPV) can reduce pneumococcal carriage and middle ear disease among Indigenous infants at seven months of age.
This is the only maternal vaccine trial in the world that has been designed to assess impact against infant middle-ear disease, a major public health problem for Indigenous Australians.
The study has become a model for community engagement (Dunbar 2007) aided by active roles of an Indigenous Reference Group and Data Safety Monitoring Board. The consent rate of 50% exceeded our expectations. There were 227 women enrolled during the third trimester and a further 86 deemed ineligible.
Randomisation was stratified by community, with retention rates through to completion of follow-up being higher in the more remote regions (94%, 95%CI 89-100%, n=71) than the Darwin urban area (86%, 95%CI 80-91%, n=156). We met the intended the sample size requirements with 201 participants completing follow-up to seven months post-delivery, a retention rate of 89%.
We have presented data at national and international conferences on immune responses to vaccination in maternal sera, cord blood and breast milk, maternal smoking rates (Johnston 2011), influenza vaccination uptake in pregnancy, and in 2012, the final results on the impact on infant middle ear disease and nasopharyngeal carriage. Manuscripts are now being prepared for publication during 2013.
Implications for policy and practice:
Maternal vaccination is an area of emerging focus for vaccine delivery. Assessing the potential efficacy of such strategies is critical to good public health policy.
Our research has found:
- Evidence of immune responses to vaccination in pregnancy in maternal sera, cord blood and breast milk, though not for all 23vPPV serotypes
- Evidence of immune responses in breast milk for those participants vaccinated at delivery
- Evidence suggestive of an impact against nasopharyngeal carriage of a limited number of serotypes related to those contained with the 23vPPV.
- No discernible impact against middle ear disease in early infancy.
Manuscripts are currently under preparation for submission for publication in peer-reviewed journals
This trial has been completed.
- Johnston, V., Thomas, D.P., McDonnell, J., & Andrews, R.M. (2011). Maternal smoking in the household during pregnancy and postpartum: findings from an Indigenous cohort in the Northern Territory. The Medical Journal of Australia, 194(10), 556-559.
- Dunbar, M., Moberley, S., Nelson, S., Leach, A.J., & Andrews, R. (2007). Clear not simple: an approach to community consultation for a maternal pneumococcal vaccine trial among Indigenous women in the Northern Territory of Australia. Vaccine, 25(13), 2385-8.