Nasopharyngeal Microbiota Profiling of Pregnant Women With Sars-Cov-2 Infection (preprint)

Background: We aimed to characterize the role of the nasopharyngeal microbiota in pregnant women with and without SARS-CoV-2 infection.Methods: Pregnant women were enrolled from a multicenter prospective population-based cohort (March-June 2020 in Barcelona, Spain) in which the status of SARS-CoV-2 infection was determined by nasopharyngeal RT–PCR and antibodies in peripheral blood. DNA was extracted from nasopharyngeal swab samples, and the V3-V4 region of the 16S rRNA of bacteria was amplified using region-specific primers. The differential abundance of taxa was tested, and alpha/beta diversity was evaluated.Results: Among 76 women, 38 were classified as positive and 38 as negative for SARS-CoV-2 infection. All positive women were diagnosed by antibodies, and 14 (37%) also had a positive RT–PCR. SARS-CoV-2 infection altered the overall composition of the nasopharyngeal microbiota (p=0.001), with a higher relative abundance of the Tenericutes and Bacteroidetes phyla and a higher abundance of the Prevotellaceae family. Infected women presented a different pattern of microbiota profiling due to beta diversity and higher richness (observed ASV<0.001) and evenness (Shannon index<0.001) at alpha diversity. These changes persisted after acute infection, as revealed by negative RT–PCR but positive antibodies, suggesting a long-lasting effect of SARS-CoV-2 in the nasopharyngeal microbiota. No significant differences were reported in mild vs. severe cases, suggesting a role of the SARS-CoV-2 infection itself but not on its severity.Conclusion: This is the first study on nasopharyngeal microbiota during pregnancy. SARS-CoV-2 infection altered the overall structure and diversity of the nasopharyngeal microbiota profile, and this effect seems to persist after the acute moment of the infection.

LOW BIRTH WEIGHT AS A RISK FACTOR FOR SEVERE COVID-19 IN ADULTS (preprint)

The identification of factors predisposing to severe COVID-19 in young adults remains partially characterized. Low birth weight (LBW) alters cardiovascular and lung development and predisposes to adult disease. We hypothesized that LBW is a risk factor for severe COVID-19 in non-elderly subjects. We analyzed a prospective cohort of 397 patients (18-70y) with laboratory-confirmed SARS-CoV-2 infection attended in a tertiary hospital, where 15% required admission to Intensive Care Unit (ICU). Perinatal and current potentially predictive variables were obtained from all patients and LBW was defined as birth weight [≤]2,500 g. Age (adjusted OR (aOR) 1.04 [1-1.07], P=0.012), male sex (aOR 3.39 [1.72-6.67], P<0.001), hypertension (aOR 3.37 [1.69-6.72], P=0.001), and LBW (aOR 3.61 [1.55-8.43], P=0.003) independently predicted admission to ICU. The area under the receiver-operating characteristics curve (AUC) of this model was 0.79 [95% CI, 0.74-0.85], with positive and negative predictive values of 29.1% and 97.6% respectively. Results were reproduced in an independent cohort, from a web-based survey in 1,822 subjects who self-reported laboratory-positive SARS-CoV-2 infection, where 46 patients (2.5%) needed ICU admission (AUC 0.74 [95% CI 0.68-0.81]). LBW seems to be an independent risk factor for severe COVID-19 in non-elderly adults and might improve the performance of risk stratification algorithms.