The Cost-Effectiveness of Group B Streptococcus Screening Strategies in Pregnant Women for the Prevention of Newborn Early-onset Group B Streptococcus : A Systematic Review

Abstract Background: Early-onset Group B Streptococcus (EOGBS) infection is one of the most prevalent neonatal infections globally, contributing to significant infant morbidity and mortality by inducing life threatening sequelae such as sepsis, meningitis and pneumonia. EOGBS infection occurs within 7 days of birth following vertical transmission of the bacteria from a colonised pregnant woman to her infant. Current strategies aimed at preventing EOGBS focus on the administration of intrapartum antibiotic prophylaxis (IAP). There is no universally agreed upon strategy for how to best identify which pregnant women should receive IAP. Currently there are four main strategies employed by health systems: 1) risk -based approach where women are assessed for risk factors for newborn EOGBS and IAP is administered to women who have at least one risk factor; 2) universal screening where all women are screened antenatally for GBS colonisation and are given IAP upon testing positive; 3) a combination of a risk-based approach and universal screening, and 4) no strategy for screening strategy with IAP administered on a case-by-case basis. Despite evidence suggesting that a universal screening strategy may be most efficacious in reducing EOGBS incidence, each screening strategy carries with it different costs and economic burdens, depending on the setting. Therefore, recommendations as to which screening strategy is most suitable must be made in the context of both sound clinical and economic evidence. Methods: This review synthesised and compared economic evaluations of maternal GBS screening strategies. A systematic search for evidence relating to GBS screening strategies was performed in the databases MEDLINE, Embase and Web of Science. Studies were included if they reported on a strategy to assess women for IAP administration and the outcomes of interest. This paper presents the findings of economic evaluations identified by this search. The economic findings of each study were compared and synthesised narratively due to significant heterogeneity among included studies preventing meta-analysis. Results: A total of 18 studies were identified for inclusion in this review. These studies, all from high-income countries, cumulatively made 58 comparisons of GBS screening strategies and cost-effectiveness analyses. Studies either compared any type of screening to no screening strategy (Universal screening vs no screening; risk-based approach vs no screening; combined screening vs no screening) or compared different screening strategies to each other. The implementation of any screening strategy was found to be cost-effective compared to none at all depending on the setting (one instance using universal screening, two using risk-factor approach and four using a combined strategy). On multiple occasions, cost-effectiveness varied significantly depending on the prevalence of maternal GBS colonisation. Discussion: This review demonstrated that in several instances the implementation of any GBS screening strategy was cost-effective compared to no strategy at all. Greater evidence is required to determine which type of screening strategy is most cost-effective, particularly in lower resource settings. The variability of cost-effectiveness by prevalence of maternal GBS colonisation indicates that a strategy's economic viability is likely context specific and should be considered before the implementation of any screening strategy.