Washington (CNN) The Trump administration official overseeing critical coronavirus testing in the US was forced out of a previous position developing vaccines at Texas A&M University -- a stint in which he made "sweeping statements about the impact of his work, not all of which turned out as some had hoped," The Washington Post reported Monday.

The Post said Assistant Secretary for Health Brett Giroir, an unofficial member of the White House's coronavirus task force who worked on vaccine projects at the university for eight years, "was told in 2015 he had 30 minutes to resign or he would be fired" from his post at the school.

Citing a local newspaper that reported on Giroir's annual evaluation, the Post said Giroir received a performance evaluation that "said he was 'more interested in promoting yourself' than the health science center where he worked. He got low marks on being a 'team player.'"

Giroir defended himself in an interview with the Post, saying he was a team player, but "not to people who act inappropriately, who are misogynistic and who are abusive to other people. I don't have a loyalty to that." The newspaper said he didn't elaborate on what he meant, saying instead: "I'll just leave it at that."

The official also told the Post that while he was "heartbroken" to leave the position, "the vaccine projects have proved valuable -- and might contribute to the development of a coronavirus vaccine."