May 7 | Weekly COVID-19 LST Report


· Trends in Patient Characteristics and COVID-19 In-Hospital Mortality in the United States During the COVID-19 Pandemic: Cardiologists from multiple American universities conducted a retrospective cohort study of 20,736 adults with COVID-19 admitted to 107 acute care hospitals between March and November 2020. They found in-hospital deaths were significantly lower in May through November compared to March and April even after adjustment for confounding variables. Though the study methodology precludes causal inferences, authors suggest rapid implementation of new isolation procedures and new techniques such as high flow nasal oxygen and prone positioning may have contributed to improved survival rates as providers gained knowledge.

· Severe SARS-CoV-2 placenta infection can impact neonatal outcome in the absence of vertical transmission: Molecular biologists and neonatologists from several institutions in Milan, Italy analyzed the placentas and clinical outcomes of 37 pregnant women who delivered between March 12 and April 23, 2020. While there was no observed evidence of vertical transmission of the virus in neonates, the virus was detected in the placental tissue of one-half of the total women (n=21) who were positive with the virus in their third trimester. In one case with high placental viral load there was extensive placental necrosis, and the infant had seizures and hypoxia requiring mechanical ventilation and oxygen supplementation for three days after birth. Authors suggest that while the relatively low viral tissue load found in the majority of placentas did not induce a harmful inflammatory response, in some situations high SARS-CoV-2 viral loads could impair neonatal development and impact outcomes in absence of vertical transmission.

· Association of Maternal SARS-CoV-2 Infection in Pregnancy With Neonatal Outcomes: Neonatologists and women's health experts from the Karolinska Institutet in Sweden studied a prospective cohort of 88,159 infants delivered to mothers who tested positive for SARS-CoV-2 between March 2020 and January 2021 using Swedish patient registries. Compared to infants born to healthy mothers in the same time frame, these infants were more likely to be admitted to the neonatal intensive care unit (11.7 vs 8.4%; odds ratio [OR], 1.47; 95%CI, 1.26-1.70) or have respiratory distress syndrome (1.2 vs 0.5%; OR, 2.40; 95%CI, 1.50-3.84), any neonatal respiratory disorder (2.8 vs 2.0%; OR, 1.42; 95%CI, 1.07-1.90), and hyperbilirubinemia (3.6 vs 2.5%; OR, 1.47; 95%CI, 1.13-1.90). Authors suggest neonates born to SARS-CoV-2 mothers are at higher risk for complications, though due to limitations in the data (imbalanced testing, heterogeneity of maternal disease severity) recommend further research into virally-altered prognosis and outcomes for newborns.

Understanding the Pathology

· Viral genomic, metagenomic and human transcriptomic characterization and prediction of the clinical forms of COVID-19: Researchers from Hôpitaux Universitaires Henri Mondor in Créteil, France used shotgun metagenomics to characterize genomic, metagenomic, and transcriptomic features of nasopharyngeal swabs from 104 COVID-19 patients. Overexpression of transcripts activating the CXCR2 pathway was seen in patients with severe pneumonia, while a T helper "Th1-Th17" profile was seen in patients with benign disease. Overall, this suggests that patients with severe COVID-19 have prolonged inflammation due to neutrophil accumulation, suggesting possible treatments such as CXCR2 antagonists and IL-8 antagonists.

Transmission & Prevention

· SARS-CoV-2 Vaccine-Induced Immune Thrombotic Thrombocytopenia: Professors from the department of pathology and laboratory medicine from the University of Pennsylvania discuss 3 independent studies describing 39 cases of thrombosis and thrombocytopenia associated with the ChAdOx1 nCoV-19 (AstraZeneca) COVID-19 vaccine. They found most patients were women under the age of 50, and that thromboses formed at unusual sites on the body with a death rate of 40%. High levels of platelet factor 4 (PF4) were detected in almost all patients. Authors suggest there is a rare link between AstraZeneca vaccination and thrombosis, and recommend future research focus on the potential role of PF4, identify patients at higher risk, and guide management.

Pathologic Antibodies to Platelet Factor 4 after ChAdOx1 nCoV-19 Vaccination: Hematologists from University College London Hospitals NHS Foundation Trust, among others, present cases of vaccine induced thrombosis and thrombocytopenia (VITT) 6 to 24 days after the first dose of ChAdOx1 nCoV-19 vaccination (AstraZeneca) in 23 patients with no prethrombotic history (except 1 patient with DVT) and in absence of heparin. They found 22 patients developed both thrombosis and thrombocytopenia while 1 had only thrombocytopenia with bruising. Anti-PF4 antibody ELISA was positive in 22/23 patients. Authors suggest providers monitor for VITT after AstraZeneca COVID-19 vaccination and propose an algorithm to help in its diagnosis and management.

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