Oral Presentation 20th Lancefield International Symposium on Streptococci and Streptococcal Diseases 2017

Do the benefits of universal group B Streptococcus (GBS) screening to prevent early-onset GBS disease (EOGBS) outweigh the harms? An evidence review for the UK National Screening Committee (NSC) (#28)

Farah Seedat 1 , Julia Geppert 1 , Chris Stinton 1 , Jacoby Patterson 1 , Colin S Brown 2 , Bee Tan 1 , Karoline Freeman 1 , Olalekan A Uthman 1 , Noel D McCarthy 1 , Esther R Robinson 3 , Samantha A Johnson 1 , Hannah Fraser 1 , Aileen Clarke 1 , Sian Taylor-Phillips 1
  1. University of Warwick Medical School, University of Warwick, Coventry, United Kingdom
  2. Bacteria Reference Department, National Infection Service, Public Health England, London, United Kingdom
  3. Birmingham Public Health Laboratory, Heartlands Hospital, Birmingham, United Kingdom

Background: In the UK, there is much debate around the prevention of EOGBS, with regular calls for the introduction of universal antenatal screening. This review, undertaken for the UK NSC, summarised recent evidence to assess GBS screening against key criteria on epidemiology, test accuracy, and screening and treatment effectiveness.

Methods: We searched Medline, Embase, and Cochrane databases as well as grey literature from surveillance reports. Participants were pregnant women ≥35 weeks and neonates <7 days. The intervention was selective recto-vaginal culture at 35-37 weeks followed by intrapartum antibiotic prophylaxis (IAP) for those found positive. Reviewers independently conducted study selection, data extraction, and quality assessment.

Results: 73 studies were included from 6,287 references. EOGBS affects 0.57 per 1,000 livebirths, and has a case fatality rate of 5.2% in the UK. Screening would be offered to approximately 718,126 term pregnant women. Approximately 150,800 (21%) would be colonised with GBS at 35-37 weeks and offered treatment, however, around 40,716 (27%) would change to negative by labour. Of the GBS-colonised women at 35-37 weeks, approximately 0.2% would have a neonate with EOGBS (350/150,800). Therefore, many women would be over-treated. Not only are the consequences of widespread IAP are unknown, the observational evidence on the effectiveness of GBS screening is limited.

Conclusion: EOGBS is an important health condition, but a more refined prevention approach is required. Antenatal culture screening is inaccurate at identifying mothers at risk of having a neonate with EOGBS, and currently the balance of harms and benefits of screening cannot be quantified.