Moncef Slaoui, the chief adviser for Operation Warp Speed, has resigned but will be available to the incoming Joe Biden administration as a consultant for about four weeks, a Biden transition official told Reuters late on Tuesday.

Slaoui’s role leading the COVID-19 vaccine development for the government effort is expected to be diminished after Jan. 20, according https://cnb.cx/3bAxEce to CNBC, which first reported the development.

The Biden team has not asked Slaoui to stay past his current contract, which includes a 30 days’ notice before termination, CNBC said.