Impact of the 23-valent pneumococcal polysaccharide vaccination in pregnancy against infant acute lower respiratory infections in the Northern Territory of Australia

Michael J Binks,Anne Balloch,Kim Mulholland,Robert S Ware,Kim M Hare,Mimi L K Tang,Cate Wilson,Ross M Andrews,Paul J Torzillo,Jane Nelson,Peter S Morris,Amanda J Leach,Jonathan R Carapetis,Sandra Nelson,Sarah A Moberley

doi:10.1186/s41479-018-0057-2

Abstract

BackgroundIndigenous children in Australia’s Northern Territory are densely colonised with the pneumococcus within weeks of birth antecedent to a high prevalence of acute lower respiratory infection (ALRI). We assessed the impact of the 23-valent pneumococcal polysaccharide vaccine (23vPPV) in pregnancy against infant ALRI in this setting.MethodsIn an open label, allocation concealed, outcome-assessor blinded, randomised controlled trial conducted in the Northern Territory of Australia, healthy Indigenous women aged 17–39 years were randomised to receive the 23vPPV during pregnancy (n = 75; 30–36 weeks gestation), at birth (n = 75), or at 7 months post-partum (n = 77). Randomisation was stratified by community of residence. In a secondary analysis, we compared the incidence of ALRI hospitalisations and ALRI clinic presentations (ascertained from electronic medical records) among infants of pregnancy vaccinees versus infants of mothers not vaccinated in pregnancy (controls) in the first year of life.ResultsALRI hospitalisation incidence was 12.3 per 100 child-years among infants of pregnancy vaccinees compared with 15.8 per 100 child-years among controls (hazard ratio (HR) 0.77, 95%CI 0.29–2.03). ALRI hospitalisations were more common among remote compared to urban infants (27.7 versus 8.6 per 100 child-years). Stratification by dwelling highlighted a differential antenatal vaccine effect against ALRI hospitalisations (urban HR 2.45, 95%CI 0.60–9.99; remote HR 0.21, 95%CI 0.04–1.08). ALRI clinic presentation incidence was similar among infants of pregnancy vaccinees and controls.ConclusionsIn this small study, antenatal 23vPPV vaccination was not associated with a reduced incidence of infant ALRI hospitalisations or ALRI clinic presentations during the first year of life. A potential differential effect between urban and remote settings warrants further investigation.Trial registrationPneuMum; ClinicalTrials.govNCT00714064.

Highlights

Indigenous children in Australia’s Northern Territory are densely colonised with the pneumococcus within weeks of birth antecedent to a high prevalence of acute lower respiratory infection (ALRI)
For the mothers not randomised to 23-valent pneumococcal polysaccharide vaccine (23vPPV) in pregnancy, 74 received 23vPPV at birth and 57/76 received the 23vPPV when offered at the 7 month visit
Within the antenatal 23vPPV group the median time between receipt of the 23vPPV in pregnancy and birth was 6 weeks; four antenatal vaccinees received their dose within two weeks of birth

Summary

Introduction

Indigenous children in Australia’s Northern Territory are densely colonised with the pneumococcus within weeks of birth antecedent to a high prevalence of acute lower respiratory infection (ALRI). While the aetiology of ALRI is difficult to characterise, the pneumococcus is commonly isolated from the middle ear discharge of Indigenous children with otitis media (23%) [7] and from bronchoalveolar lavages collected from Indigenous children with chronic suppurative lung disease (33%) [8]. Pragmatic strategies such as maternal vaccination are essential to reduce the burden of early-onset pneumococcal infection in this region

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Discussion

Conclusion