Dr. Scott Atlas, a controversial pandemic adviser to President Donald Trump who was lambasted for supporting the idea of herd immunity to deal with the COVID-19 pandemic, resigned from his role on Monday.

“I worked hard with a singular focus — to save lives and help Americans through this pandemic,” Atlas, a neuroradiology professor, said in his resignation letter, adding that he “always relied on the latest science and evidence.”

He was serving a 130-day detail as a special government employee, and his term was set to expire this week. His resignation was first reported by Fox News.