FormalPara Linda J. Saif

is at the Ohio Agricultural Research and Development Center at The Ohio State University College of Veterinary Medicine in Wooster, Ohio, USA.

FormalPara Dennis Burton

is at the Scripps Research Institute in La Jolla, California, USA.

FormalPara Erica Ollmann Saphire

is at the La Jolla Institute for Immunology, La Jolla, California, USA.

FormalPara George Scangos

is at Vir Biotechnology in San Francisco, California, USA.

FormalPara George Georgiou

is at the University of Texas in Austin, Texas, USA.

FormalPara Tillman Gerngross

is at Dartmouth College in Hanover, New Hampshire, USA.

FormalPara Jake Glanville

is at Distributed Bio in South San Francisco, California, USA.

In October, US President Donald Trump received Regeneron Pharmaceuticals’ experimental monoclonal antibody (mAb) cocktail REGN-COV2 as part of his treatment for COVID-19. Buoyed by a positive response, both Regeneron and Eli Lilly have filed requests for Emergency Use Authorization from the US Food and Drug Administration, although Lilly had to pause clinical testing because the trial crossed a predetermined safety threshold. Lilly’s product, LY-CoV555, is a human IgG1 mAb targeting the spike (S) glycoprotein. These and 11 other experimental mAb treatments targeting the SARS-CoV-2 S protein are undergoing human testing (Table 1), with at least another 150 other antibodies in discovery research. Neutralizing mAbs promise an adjunct to vaccines and traditional drugs in the treatment of COVID-19. Here, a group of experts comments on the state of the art in antiviral mAb discovery and development, and the challenges ahead.