Review on the association of Group B Streptococcus capsular antibody and protection against invasive disease in infants

Abstract

A trivalent Group B streptococcus (GBS) polysaccharide-protein conjugate vaccine for vaccination of pregnant women is under development to protect their newborns against invasive GBS disease. Establishing sero-correlates of protection against invasive GBS disease in infants could expedite the licensure pathway of polysaccharide-protein conjugate vaccine. A systematic review of studies reporting on the association of capsular antibodies and invasive GBS disease in infants and colonization in women or newborns was undertaken. Most studies that described maternal and/or infant capsular antibody levels in infants with invasive GBS disease identified an association between low capsular antibody levels in invasive GBS cases compared to controls. Different assay methods and the lack of standardized reference ranges for serotype-specific antibody levels makes it difficult to select an antibody level that may be used as a reliable sero-correlate of protection. Further studies using standardized methods are warranted.

Keywords:

• capsular antibodies
• GBS
• infants
• sero-correlates
• vaccine

Financial & competing interests disclosure

SA Madhi has received Institutional Grant support from Novartis on GBS and is also Clinical Trial Investigator on Novartis GBS vaccine program. Z Dangor is funded in part by the Carnegie Corporation (Grant number B8749) of New York and Discovery Foundation. G Kwatra is funded by National Research Foundation/Department of Science and Technology. SA Madhi is funded in part by National Research Foundation/Department of Science and Technology: South African Research Chair Initiative Program and Medical Research Council of South Africa. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Group B Streptococcus (GBS) is the leading cause of neonatal sepsis and meningitis, despite current preventative measures.

• Vaccinating pregnant women against GBS infection may protect infants from invasive GBS disease and may be an alternative strategy.

• Establishing sero-correlates of protection against specific capsular epitopes causing disease may favor the licensure of the GBS polysaccharide-protein conjugate vaccine.

• Limited studies using nonstandardized methods have identified an association between low capsular GBS antibodies and the risk of developing invasive disease; however, no established measure of protection can be drawn from these.

• Further studies using standardized methods are warranted in a diversity of settings to establish a sero-correlate of protection against early- and late-onset disease.

Notes