Risk based preventionIn November 2003, the Royal College of Obstetricians &

Gynaecologists1 recommended that women with selected

risk factors for early-onset group B Strep (EOGBS) infection

in their babies should be offered intrapartum antimicrobial

prophylaxis (IAP).

It had been expected that a risk-based prevention would reduce the rate of EOGBS infection by 50%2. However, the rate of EOGBS infections in babies has not fallen since the guidelines were introduced.

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Testing based preventionMost developed countries with a group B Strep prevention

strategy offer pregnant women tests for carriage, with IAP

offered to those carrying group B Strep, plus to those who

do not have a test result but who have risk factors. In these

countries, the rate of EOGBS infection has fallen significantly.

In the US, guidelines on preventing EOGBS disease were issued in 1996 and revised in in 2002 and 2010. These recommend that all women have vaginal-rectal testing for group B Strep colonisation at 35-37 weeks’ gestation. Implementation of the guidelines has been good. One study4 found that 85% of pregnant women were screened for group B Strep. Among those screened, 98% had results available at delivery. Eighty-five percent of women with an indication for IAP received treatment.

0

2003 2004 2005 2006 2007 2008 2009 2010 2011 2012

Early onset rate/1000 live births Late onset rate/1000 live births

RCOG GUIDELINES

INTRODUCED

Group B Strep bacteraemia in babies in England, Wales & Northern Ireland 2003-2013

Slight increase since RCOG GBS guidelines introduced in Nov 2003

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1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

Rate of early and late onset group B Strep disease.Active Bacterial Core surveillance areas, 1990-2008

The graph shows the rate of EOGBS infection in the US5 has fallen dramatically since the introduction of IAP and screening for group B Strep carriage, although the rate of LOGBS infection has not changed. Data published subsequently shows the rates of group B Strep infection have fallen to 0.24/1,000 live births for early and 0.25/1,000 for late onset group B Strep infections in 2013.6

This graph shows culture-proven early onset (0-6 days) and late onset (7-90 days) group B Strep infections voluntarily reported to Public Health England (and its predecessors)3. The true rate will be higher.

The Royal College of Obstetricians & Gynaecologists states that “Routine bacteriological screening of all pregnant women for antenatal Group B Strep carriage is not recommended.”

Prevention strategies for early-onset group B Strep infection

1 | RCOG guidelines 2003, updated 2012 http://www.rcog.org.uk/womens-health/clinical-guidance/prevention-early-onset-neonatal-group-b-streptococcal-disease-green-#

2 | Prevention of early onset neonatal Group B Strep infection. McCartney AC. Journal of Medical Screening, 2001.

3 | PHE source data http://ow.ly/FEMfW

4 | Van Dyke et al. Evaluation of Universal Antenatal Screening for Group B Streptococcus. N Engl J Med. 2009 Jun 18;360(25):2626-36.

5 | Adapted from Jordan HT, Farley MM, Craig A, et al. Revisiting the need for vaccine prevention of late-onset neonatal group B streptococcal disease. Pediatr Infect Dis J 2008;27:1057-64.

6 | Centers for Disease Control and Prevention. 2013. Active Bacterial Core Surveillance Report, Emerging Infections Program Network, Group B Streptococcus, 2013. http://www.cdc.gov/abcs/reports-findings/survreports/group B Strep13.html