In the study of small series, vascular angiogenesis distinguished the pulmonary pathobiology of Covid-19 from that of equally severe influenza virus infection. The universality and clinical implications of our observations require further research to define. (Funded by the National Institutes of Health and others.)

The study report the presence of pulmonary intussusceptive angiogenesis and other pulmonary vascular features in the lungs of seven patients who died from Covid-19. Additional work is needed to relate our findings to the clinical course in these patients. To aid others in their research, our full data set is available on the Vivli platform (https://vivli.org/. opens in new tab) and can be requested with the use of the following digital object identifier: https://doi.org/10.25934/00005576. opens in new tab.

Supported by grants (HL94567 and HL134229, to Drs. Ackermann and Mentzer) from the National Institutes of Health, a grant from the Botnar Research Centre for Child Health (to Dr. Tzankov), a European Research Council Consolidator Grant (XHale) (771883, to Dr. Jonigk), and a grant (KFO311, to Dr. Jonigk) from Deutsche Forschungsgemeinschaft (Project Z2).

Disclosure forms provided by the authors are available with the full text of this article at NEJM.org.

This article was published on May 21, 2020, at NEJM.org.

We thank Kerstin Bahr, Jan Hinrich Braesen, Peter Braubach, Emily Brouwer, Annette Mueller Brechlin, Regina Engelhardt, Jasmin Haslbauer, Anne Hoefer, Nicole Kroenke, Thomas Menter, Mahtab Taleb Naghsh, Christina Petzold, Vincent Schmidt, and Pauline Tittmann for technical support; Peter Boor of the German Covid-19 registry; and Lynnette Sholl, Hans Kreipe, Hans Michael Kvasnicka, and Jean Connors for helpful comments. Dr. Jonigk thanks Anita Swiatlak for her continued support.

Author Affiliations
From the Institute of Pathology and Department of Molecular Pathology, Helios University Clinic Wuppertal, University of Witten–Herdecke, Wuppertal (M.A.), the Institute of Functional and Clinical Anatomy, University Medical Center of the Johannes Gutenberg University Mainz, Mainz (M.A.), the Institute of Pathology (M.K., F.L., C.W., H.S., D.J.), the Department of Cardiothoracic, Transplantation, and Vascular Surgery (A.H.), and the Clinic of Pneumology (T.W.), Hannover Medical School, and the German Center for Lung Research, Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH) (M.K., A.H., T.W., F.L., C.W., H.S., D.J.), Hannover — all in Germany; the Laboratory of Respiratory Diseases, BREATH, Department of Chronic Diseases, Metabolism, and Aging, KU Leuven, Leuven, Belgium (S.E.V., A.V.); the Institute of Pathology and Medical Genetics, University Hospital Basel, Basel, Switzerland (A.T.); and the Angiogenesis Foundation, Cambridge (W.W.L., V.W.L.), and the Laboratory of Adaptive and Regenerative Biology and the Division of Thoracic Surgery, Brigham and Women’s Hospital, Harvard Medical School, Boston (S.J.M.) — all in Massachusetts.

Address reprint requests to Dr. Mentzer at the Division of Thoracic Surgery, Brigham and Women’s Hospital, Harvard Medical School, 75 Francis St., Boston, MA 02115, or at [email protected].