Placental pathology, neonatal birth weight, and Apgar score in acute and distant SARS-CoV-2 infection

Background:: Most research on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during pregnancy has been on acute infections with limited data on the effect of distant infection. Aim:: We examined placental pathology and neonatal outcomes in distant SARS-CoV-2 infection earlier in pregnancy compared to acute infections late in pregnancy/at birth and to non-SARS-CoV-2 infected patients with other placental pathologies/clinical presentations. Methods:: Placentas birthed to unvaccinated patients with SARS-CoV-2 reverse transcription–polymerase chain reaction (RT-PCR) testing and serology testing results from time of delivery were included in this study. A total of 514 singleton placentas between April 18, 2020, and July 26, 2021, were included: 77 acute SARS-CoV-2 infection (RT-PCR positive and serology negative);222 distant SARS-CoV-2 infection (RT-PCR negative but serology IgG-positive);and 215 non-SARS-Cov-2 infected (RT-PCR negative, serology negative, and history negative) with other placental pathologies: preeclampsia/hypertension, intrauterine growth restriction (IUGR), diabetes, chorioamnionitis, and meconium. Placental pathology findings, Apgar scores, and neonatal birth weights were compared. Results:: Placentas from the acute group had significantly more villous agglutination (10.4%, P = 0.015) and eosinophilic T-cell vasculitis (5.2%, P = 0.004) compared to placentas from the distant group (2.7% and 0%) and non-SARS-CoV-2 placentas (1.9% and 0.9%). One acute case showed SARS-CoV-2 placentitis and resulted in preterm delivery at 25 weeks. Both the preeclampsia/hypertension and the IUGR groups showed significantly more maternal vascular malperfusion findings compared to the acute (6.5%, 6.5% and 1.3%) and distant (7.7%, 7.7%, and 3.2%) groups. Fetal vascular malperfusion findings such as thrombosis of fetal vessels (17.4% P = 0.042) and intramural fibrin deposition (21.7% P = 0.026) were significantly higher in the IUGR group compared to acute (7.8%;2.6%) and distant (3.6%;8.1%) infection. Many neonates born to patients infected with SARS-CoV-2 had birth weights outside of 95% confidence range of observed birth weights. There was no association of Apgar scores with infection status or placental pathology. Conclusion:: Acute and distant SARS-CoV-2 infections present differing placental pathology. Relevance for Patients:: SARS-CoV-2 infection during pregnancy has demonstrable effects on the placenta with potential significant impacts for maternal and fetal health. Prevention of maternal SARS-CoV-2 infection, primarily through vaccination, remains the best mitigation strategy to prevent sequelae of maternal SARS-CoV-2 infection.

COVID-19 Literature Knowledge Graph Construction and Drug Repurposing Report Generation

To combat COVID-19, both clinicians and scientists need to digest vast amounts of relevant biomedical knowledge in scientific literature to understand the disease mechanism and related biological functions. We have developed a novel and comprehensive knowledge discovery framework, COVID-KG to extract fine-grained multimedia knowledge elements (entities and their visual chemical structures, relations and events) from scientific literature. We then exploit the constructed multimedia knowledge graphs (KGs) for question answering and report generation, using drug repurposing as a case study. Our framework also provides detailed contextual sentences, subfigures, and knowledge subgraphs as evidence. All of the data, KGs, reports(1), resources, and shared services are publicly available(2).

Exploration and Discovery of the COVID-19 Literature through Semantic Visualization

We propose semantic visualization as a linguistic visual analytic method. It can enable exploration and discovery over large datasets of complex networks by exploiting the semantics of the relations in them. This involves extracting information, applying parameter reduction operations, building hierarchical data representation and designing visualization. We also present the accompanying COVID-SEMVIZ, a searchable and interactive visualization system for knowledge exploration of COVID-19 data to demonstrate the application of our proposed method.1 In the user studies, users found that semantic visualization-powered COVID-SEMVIZ is helpful in terms of finding relevant information and discovering unknown associations. © 2021 Association for Computational Linguistics.

Transmission of COVID-19 virus by cough-induced particles in an airliner cabin section

With airborne transmissions found as one of the major transmission routes of SARS-CoV-2, its transmission in airliner cabin environments drew special attention due to high number of imported cases and in-cabin transmissions. This study numerically investigated the transmission of COVID-19 by cough-induced particles in a cabin section of Boeing 737 model. One passenger was coughing in each case, while cough particles with measured size distributions were released during coughs and were tracked using the Lagrangian framework. Outcomes revealed that cough flow released by passengers could develop rapidly into a strong turbulent cough jet, breaking up the local airflow field. The released cough particles were largely dominated by the cough jet within 5 s, especially the first 1.5 s. Deposition of particles under 100 µm were relatively delayed when released from a window-seat location. Small particles (under 50 µm) released by a window-seat passenger were more likely to spread widely in the studied cabin section, which could lead to the highest exposure risks to nearby passengers. Also, due to ventilation design and seating arrangement, cough particles released by the middle-seat passenger were found easily trapped in his/her own local environment. Cough particles released from aisle-seat passengers had the least exposure risk to adjacent passengers. © 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.