Association of Group B Streptococcus (GBS) Serum Serotype-Specific Anticapsular Immunoglobulin G Concentration and Risk Reduction for Invasive GBS Disease in South African Infants: An Observational Birth-Cohort, Matched Case-Control Study
Autor: | Clare L. Cutland, Shabir A. Madhi, Ziyaad Dangor, Carmen Briner, Gaurav Kwatra, Jeanette Wadula, Wenji Pu, Ouzama Henry, Stephanie Jones, Alane Izu, Yasmin Adam, Andrew Moultrie |
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Rok vydání: | 2020 |
Předmět: |
Microbiology (medical)
Serotype medicine.medical_specialty Serogroup medicine.disease_cause Gastroenterology Group B Immunoglobulin G Streptococcus agalactiae Serology Pregnancy Conjugate vaccine Streptococcal Infections Internal medicine medicine Humans biology Streptococcus business.industry Infant Newborn Case-control study Infant Gestational age Antibodies Bacterial Infectious Diseases Case-Control Studies biology.protein Female business Risk Reduction Behavior |
Zdroj: | Clinical Infectious Diseases. 73:e1170-e1180 |
ISSN: | 1537-6591 1058-4838 |
Popis: | Background Licensure of a group B Streptococcus (GBS) polysaccharide-protein conjugate vaccine for protecting infants against invasive GBS disease (IGbsD) will likely need to be based on demonstrating vaccine safety in pregnant women, and benchmarking immunogenicity against a serological threshold associated with risk reduction of IGbsD. We investigated the association between naturally derived GBS serotype Ia and III IgG and risk reduction of IGbsD in infants ≤90 days of age. Methods In a matched case-control study, IGbsD cases were identified from a cohort of 38 233 mother-newborn dyads. Mothers colonized vaginally with serotype Ia or III at birth and their healthy infants were eligible as matched controls. GBS serotype-specific anticapsular immunoglobulin G (IgG) was measured on maternal and cord blood/infant sera by multiplex Luminex assay, and the IgG threshold associated with 90% risk reduction of IGbsD was derived by estimating absolute disease risk. Results In infants born at ≥34 weeks’ gestational age, cord-blood IgG geometric mean concentrations (GMCs) were lower in cases than controls for serotypes Ia (0.05 vs 0.50 µg/mL; P = .004) and III (0.20 vs 0.38 µg/mL; P = .078). Cord-blood IgG concentrations ≥1.04 and ≥1.53 µg/mL were associated with 90% risk reduction of serotype Ia and III IGbsD, respectively. The maternal sera IgG threshold associated with 90% risk reduction was ≥2.31 µg/mL and ≥3.41 µg/mL for serotypes Ia and III, respectively. Conclusions The threshold associated with a reduced risk for serotype Ia and III IGbsD identified on infant sera supports the case for licensure of a GBS polysaccharide-protein conjugate vaccine based on an immunogenicity evaluation benchmarked against the defined thresholds. Clinical Trials Registration NCT02215226. |
Databáze: | OpenAIRE |
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