Findings
In these 2 phase 2 randomized clinical trials within the Accelerating COVID-19 Therapeutic Interventions and Vaccines (ACTIV)–2/A5401 platform, tixagevimab-cilgavimab given intramuscularly or intravenously was safe but did not shorten symptom duration. Fewer participants who received intramuscular treatment vs placebo had quantifiable SARS-CoV-2 RNA in nasopharyngeal swabs at day 7.