The former Aetna president, who joined CVS in 2018 through its acquisition of the insurer, struck many as perfectly suited for the moment. Throughout her career at Cigna, Magellan Health Services, and Aetna, Lynch made a name for herself as someone capable of both wrangling complicated projects (she ran the Aetna-CVS integration) and handling crises (she led CVS’s early response to COVID-19). Now, four months into the job, she has overseen 20 million of the total 274 million vaccinations administered in the U.S. 

It’s an unprecedented job for an unprecedented leader. In running the No. 4 company on this year’s Fortune 500 list, Lynch makes a bit of history of her own. CVS is the highest-ranking company ever to be led by a female chief executive in the 67-year history of the list. 

Fighting the pandemic has also helped Lynch move the company closer to the ambitious goal set by her predecessor, Larry Merlo: transform CVS from drugstore chain to health care titan. Nine percent of first-time customers who came to CVS for a COVID test also filled a new prescription. “Vaccines and testing have put CVS on the map to be a health destination,” says Lynch. The revenue doesn’t hurt either. While CVS declined to disclose how much money it has made administering vaccines, the government recently raised its reimbursement rate from $28 to $40 per dose. 

Lynch is also looking ahead to the post-COVID future. In 2022, the company will debut its first co-branded Aetna/CVS insurance product, hoping to woo the market of some 15 million who buy coverage on the Affordable Care Act exchanges. “CVS is a trusted brand,” Lynch says of the decision to carry the name into the insurance realm. “We’ve made it more trusted with the work we did on testing and vaccines.” 

This article appears in the June/July 2021 issue of Fortune with the headline, “Vaccine queen.”