Alterations in Vaginal Microbiota among Pregnant Women with COVID-19

Abstract Background: The maintenance of vaginal microbiota is an important factor to achieve ideal pregnancy outcomes. Coronavirus disease (COVID-19) has been shown to have potential adverse effects on pregnancy and neonatal outcomes. Pregnancy itself is a risk factor for the severity of COVID-19, with an increased risk of intensive care unit (ICU) admission, maternal morbidity, and mortality. the role of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection in vaginal microbiome composition in pregnant women with COVID-19 has not yet been investigated. Therefore, we anticipate that COVID-19 may unfavorably affect the composition of the vaginal microbiota, resulting in adverse pregnancy outcomes. We aimed to describe the alterations of the composition of vaginal microbiota in pregnant women with COVID-19.Results: A prospective case-control study was conducted among 19 pregnant women with COVID-19 and 28 healthy controls matched according to the gestational week and age. The vaginal swabs were collected during the active phase of infection and consecutively, within a month after recovering from infection. In three patients, longitudinal samples before, in the course, and after infection were also obtained. The microbiome alterations were examined by 16S rRNA gene sequencing. We indicated that COVID-19 was associated with vaginal dysbiosis during pregnancy, which was indicated by an increased alpha diversity index. There was a significantly decrease in Firmicutes (P=0.007) and Lactobacillus (P=0.019) with an increase in Bacteroidetes (P=0.024) in the COVID-19 group. In the moderate/severe group, increased amounts of Ureaplasma and vanishing of Lactobacillus gasseri were found in women, compared to the asymptomatic or mild group (P=0.001). In longitudinal analysis, elevation of Actinobacteria with reduction of Firmicutes and Bacteroides were indicated during the active phase. Conclusions: The study revealed vaginal dysbiosis with a low abundance of Lactobacillus and an increase in Bacteroidetes in relation to SARS-CoV-2 infection. Vaginal dysbiosis in COVID-19 could be a contributing factor in pregnancy adverse outcomes. Trial registration: clinicaltrials, Registered 15 November 2019, https://www.clinicaltrials.gov/ct2/show/NCT04165252?cond=microbiota&cntry=TR&draw=3&rank=12