Population-based active surveillance for neonatal group B streptococcal infections in Alberta, Canada: implications for vaccine formulation

Pediatr Infect Dis J. 2001 Sep;20(9):879-84. doi: 10.1097/00006454-200109000-00011.


Background: Knowledge of circulating serotypes of group B Streptococcus (GBS) is important for formulation of vaccines. There are no Canadian data on the serotype distribution of neonatal GBS isolates.

Methods: Using a retrospective laboratory and health record survey between 1993 and 1994 (before introduction of Canadian prevention guidelines) and prospective active laboratory-based surveillance from 1995 to 1999 of all laboratories in Alberta, we identified 168 cases of invasive neonatal GBS infections including stillbirths among 262,398 total births; 118 of 123 (96%) isolates from 1995 to 1999 were serotyped, and the corresponding neonatal health records were reviewed.

Results: The average annual incidence was 0.64 of 1000 total births/year. Of these 95 (57%) had early onset disease (EOD), 15 (9%) were still births and 58 (34%) had late onset disease (LOD). Eighty-one percent of EOD cases were caused by serotypes Ia, Ia/c, Ia/c/R, III, III/R and V, V/R, whereas 81% of LOD cases were caused by serotypes III and III/R. GBS serotypes containing the C protein along with serotypes III and V as a group constituted 91% (107 of 118) of all GBS cases in our population. The most common clinical presentation was bacteremia without focus (74%) followed by meningitis (14%) and pneumonia (12%). During 1995 to 1999, in addition to 13 stillbirths, there were 6 of 64 (9%) neonatal deaths among EOD cases and 1 of 46 (2%) neonatal death among LOD cases.

Conclusions: In this population-based study stillbirths account for a proportion of cases that are not routinely counted and represent a group for which intrapartum antibiotics would likely not be effective, but potentially preventable by vaccination. Inclusion of serotypes Ia, III and V in a conjugate vaccine or serotypes III and V conjugated with the C protein in a GBS vaccine could theoretically provide protection against the majority of GBS invasive disease in Alberta neonates.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alberta / epidemiology
  • Chi-Square Distribution
  • Female
  • Humans
  • Incidence
  • Infant, Newborn
  • Male
  • Poisson Distribution
  • Population Surveillance
  • Retrospective Studies
  • Risk Factors
  • Streptococcal Infections / epidemiology*
  • Streptococcal Infections / prevention & control*
  • Streptococcal Vaccines / administration & dosage*
  • Streptococcus agalactiae / isolation & purification*
  • Vaccination / standards*
  • Vaccination / trends


  • Streptococcal Vaccines