Gerald Ong'ayo, Kenya
KEMRI-Wellcome Trust Research Programme EpidemiologyAuthor Of 1 Presentation
PNEUMOCOCCAL CONJUGATE VACCINE DOSE-RANGING STUDIES IN HUMANS: A SYSTEMATIC REVIEW (ID 268)
Abstract
Background
Reduced dose vaccination with pneumococcal conjugate vaccines may protect against infection. We sought to examine the relationship between the dose of polysaccharide in conjugate vaccines (PCVs) and immunogenicity.
Methods
A systematic review of English publications that evaluated variable dose immunogenicity of PCVs in humans was performed in Medline and Embase databases (Ovid SP) in August 2019. Results were synthesised descriptively due to the heterogeneity of product valency, content and vaccine schedule.
Results
We identified 1691 articles after de-duplication; 9 studies met our inclusion criteria; 2 in adults, 6 in children and 1 in both. Doses of polysaccharide evaluated ranged from 0.44 mcg to 17.6 mcg. Thirty days after vaccination following a single dose or 2p+1 schedule, all doses tested in infants achieved mean IgG concentrations (GMCs) above the acceptable correlate of protection (COP; 0.35 mcg) and only three GMCs' 95% confidence intervals crossed the COP. All doses tested in adults achieved GMCs that were comparable to those considered protective in children who have received 3 standard vaccine doses.
Conclusions
For some products, the mean antibody concentrations induced for some pneumococcal serotypes increased with increasing doses of the polysaccharide but the functional significance of these is uncertain.