Detection of SARS-CoV-2 in Neonatal Autopsy Tissues and Placenta

Abstract

Severe coronavirus disease in neonates is rare. We analyzed clinical, laboratory, and autopsy findings from a neonate in the United States who was delivered at 25 weeks of gestation and died 4 days after birth; the mother had asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and preeclampsia. We observed severe diffuse alveolar damage and localized SARS-CoV-2 by immunohistochemistry, in situ hybridization, and electron microscopy of the lungs of the neonate. We localized SARS-CoV-2 RNA in neonatal heart and liver vascular endothelium by using in situ hybridization and detected SARS-CoV-2 RNA in neonatal and placental tissues by using reverse transcription PCR. Subgenomic reverse transcription PCR suggested viral replication in lung/airway, heart, and liver. These findings indicate that in utero SARS-CoV-2 transmission contributed to this neonatal death.

Keywords: 2019 novel coronavirus disease; COVID-19; SARS-CoV-2; autopsy; coronavirus disease; infant; newborn; pregnancy; respiratory infections; severe acute respiratory syndrome coronavirus 2; vertical transmission; viruses; zoonoses.

Figure 1

Pulmonary histopathologic, immunohistochemical (IHC), in situ hybridization, and ultrastructural findings in tissues from a neonate in the United States with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). A) Lower magnification of the lung showing diffuse alveolar damage, characterized by type II pneumocyte hyperplasia (arrowhead), hyaline membrane (arrow), and interstitial mononuclear infiltrate. Original magnification ×20. B) Extensive intra-alveolar immunostaining by spike protein SARS-CoV-2 IHC assay. Original magnification ×40. C) Double-stain IHC assay showing rare macrophages with SARS-CoV-2/CD-163–positive immunostaining. Red, SARS-CoV-2; brown, CD-163 antibody (arrow). Original magnification ×63. D) Extensive staining of SARS-CoV-2 genomic RNA in pneumocytes by nucleocapsid gene in situ hybridization assay. Original magnification ×10. E) Electron microscopy (EM) image of a pneumocyte containing accumulations of intracellular viral particles. Scale bar indicates 200 nm; viral particles were on average 65 nm in diameter, smaller than commonly observed because of shrinkage during processing. F) Immunostaining of tracheal epithelial cells (arrowhead) and submucosal glands (arrow) by SARS-CoV-2 nucleocapsid IHC assay. Original magnification ×20. G) EM image of a ciliated epithelial cell with extracellular viral particles (arrow) associated with the cilia. Scale bar indicates 200 nm. EM images were collected from 4-μm sections of formalin-fixed, paraffin-embedded tissues affixed to glass slides that were embedded for EM.

Figure 2

In situ hybridization (ISH) slides demonstrating localization of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genomic RNA in heart, liver, and lymph node tissues and electron microscopic evidence of viral particles in heart tissue from neonate in the United States that died with SARS-CoV-2 infection and placental histopathology and angiotensin-converting enzyme-2 immunohistochemical stain slides. A) SARS-CoV-2 RNA staining by nucleocapsid gene ISH assay in the endothelial cells in myocardium vessel walls (arrow). Original magnification ×20. B) Extracellular virus particles in the connective tissue of the heart (arrow). Scale bar indicates 100 nm. C) Intravascular staining by nucleocapsid gene ISH assay in the liver parenchyma (arrow). Original magnification ×20. D) Extensive nucleocapsid gene ISH staining within macrophages of subcapsular sinus of lymphoid follicle in the submucosa of upper airway (arrow). Original magnification ×10. E) Second trimester placenta with fibrinoid necrosis (arrow). Original magnification ×20. F) Angiotensin-converting enzyme 2 immunostaining in the membrane polarized on the maternal lake side in the syncytiotrophoblast (arrow). Original magnification ×63.