NEW YORK — Moderna announced on Thursday it is working a single vaccine that combines a booster dose against COVID-19 with its experimental flu shot.

The company said it hopes to eventually add vaccines it is working on for respiratory syncytial virus and other respiratory diseases as an annual shot.

“We believe this is a very large opportunity that is ahead of us, if we could bring to market a high efficacy pan-respiratory annual booster,” Moderna chief executive officer Stéphane Bancel said during a presentation to update investors on its drugs in development.

“We believe Moderna could be first to market in this important new opportunity,” he added.