(Reuters) – Walmart (NYSE:WMT) said on Tuesday it will expand online primary care facilities as part of its employee health insurance plan to its workers in 28 U.S. states.

The retailer employs more than 2 million people, according to a regulatory filing, and is the largest private employer in the United States.

Walmart said it has partnered with virtual healthcare services provider Included Health to expand its online primary care services, which already have a presence in about 21 states.

As part of the expansion, which kicks off this week, employees can access virtual care options including digestive health and physical therapy as well as a few diagnostic tests at home, starting early next year, the retailer said.

Walmart said in a blog post it had observed an 11% reduction in the total costs of care for its employees and their families from a pilot run for its virtual primary care service.