File photo shows a vial of COVID-19 vaccine developed by Moderna Inc., taken on May 24, 2021, in Aichi Prefecture, central Japan. (Kyodo)

WASHINGTON - U.S. biotechnology firm Moderna Inc. said Friday it is filing patent infringement lawsuits over a COVID-19 vaccine developed by U.S. pharmaceutical giant Pfizer Inc. and its German partner BioNTech SE, alleging a key technology was copied.