(Bloomberg) -- Walmart Inc. named pharmaceutical industry veteran John Wigneswaran as its new chief medical officer, filling a role that had been vacant since March.

Wigneswaran was previously chief medical officer of pharmacy-benefits manager Express Scripts, which was acquired by insurance giant Cigna Corp. in 2018. He replaces Tom Van Gilder, the retailer’s first-ever chief medical officer, who left the post earlier this year.

Wigneswaram joins Walmart as the retail giant looks to expand its presence in the health-care market, where it battles pharmacy giants CVS Health Corp. and Walgreens Boots Alliance, as well as Amazon.com Inc., which is pushing to sell more medications online.

Walmart has opened low-cost medical clinics, acquired a telehealth company and is also rolling out its own brand of low-cost insulin to capture more of the nation’s drug spending. It’s also grappling with the contentious issue of Covid-19 vaccinations, and said Friday it would require all of its regional staffers and those at its Bentonville, Arkansas, headquarters to be inoculated by Oct. 4.

Wigneswaran joined Express Scripts in 2018, and previously served as vice president of clinical affairs at DaVita Inc., an operator of kidney dialysis centers. Before that, he worked at Fresenius Medical Care and also Johnson & Johnson.

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