Sarah Tuneberg, who leads the state’s COVID-19 testing and containment team, will resign effective Jan. 21.

“My superpower is building big things really fast. And I have had the incredible opportunity to do that in this difficult time of COVID-19 in Colorado,” Tuneberg told CPR. “I’m super proud of the work. And now we’re sort of in this really wonderful transition period.”

Tuneberg joined the Polis Administration in March, and her responsibilities included tracking and testing for the novel coronavirus. Prior to her current position, she worked for three years as the CEO of Geospiza, a climate risk assessment organization. She graduated with a master’s degree in public health from Tulane University and spent a decade-and-a-half in various consulting and public health-oriented positions.

Her departure comes amid positive and perilous developments in the pandemic: by Tuesday, Colorado had administered nearly 74,000 doses of COVID-19 vaccinations, weeks after federal authorities approved two types of drug. However, Colorado also discovered the first American cases of a more transmissible mutation of the virus.

“When she accepted the position, I knew it might not be for the long term, but I am grateful for her service and she will always have a home at CDPHE,” said the department’s executive director, Jill Hunsaker Ryan, according to CPR.

Tuneberg worked with private laboratories to increase testing capacity and helped debut a contact tracing and investigation system. As of Dec. 29, the state had conducted 4.3 million tests, covering nearly 2.2 million people.