GBS antenatal screening and recto-vaginal colonization rates before and during the COVID-19 pandemic

ABSTRACT

Background: The SARS-CoV-2 pandemic has resulted in the implementation of recommendations to reduce interpersonal contact. From March 2020, rules were applied also in Italian Obstetrics units. Recent data report reduced rates of nosocomial and surgical site infections during the pandemic period. We wonder whether measures for containment of SARS-CoV-2 transmission would affect Group B streptococcus (GBS) maternal recto-vaginal colonization rates, usually screened at 36-37 weeks' gestation. The primary endpoint of this study was to evaluate the rate of maternal GBS colonization at antenatal screening. Method(s) This is a retrospective observational study (carried out in district of Modena), comparing maternal GBS colonization rates in the pre-COVID-19 (2018-2019) and during the pandemic period (2020-2021). Rates of rectovaginal colonization were retrieved from the laboratory database. The total number of deliveries was collected. Data were analyzed by using the Chi-Squared test, also evaluating the adherence to the GBS screening. A p-value < 0.05 was considered significant. Result(s) A total of 10968 and 10802 deliveries occurred in the pre-COVID-19 and the Pandemic period respectively (overall reduction in deliveries of 1.5%). The adherence to the antenatal GBS screening declined from 96.6% (pre-COVID-19 era) to 91.6% (pandemic era, p<0.001). Notably, the proportion of positive GBS screening remained stable (18.3% in 2018-2019 and 18.2% in 2020-2021, p=0.80). Conclusion(s) During the SARS-CoV-2 pandemic, we reported a reduced adherence to antenatal GBS screening. SARS-CoV-2 containment measures adopted by both the population and hospital professionals did not affect GBS colonization rates.