"They live in fear and dread," Kernaghan told ABCNews.com.
Walmart said its policy does account for extraordinary circumstances, telling "Good Morning America" that no employee will be fired for getting H1N1 flu.
"Our attendance policy is written in a way that is flexible to meet the needs of our associates, but, by the same token, it allows us to take care of our customers and run our business."
But some workers see it differently.
"You go to work sick, you try to do the best that you can," said the second employee "GMA" interviewed. "It's terrible."
Experts agreed with recommendations from the CDC, which advises people in the work force to stay home if they have flu-like symptoms and employers to develop "flexible leave policies" so that workers can stay home and care for themselves and their families "without fear of losing their jobs."
"I do believe Walmart is creating a public health threat by encouraging workers to come to work [sick]," said Robert Field, professor of health management and policy at the Drexel University School of Public Health in Philadelphia. "It is in a position, as a retailer, to create particular exposures for the public. ... It's such a ubiquitous store, and it particularly caters to families and kids who are the ones most likely to spread the disease."
Elizabeth Casman, associate research professor in public policy at Carnegie Mellon University in Pittsburgh, said that about one out of three flu cases may be spread by mucus on the hand touching an object, pointed out that this makes certain situations such as the checkout counter at a store, for example, a high-risk area.
The CDC recommends people remain home until 24 hours after flu symptoms disappear to prevent spreading infection, and it estimates that a sick worker can infect one in 10 co-workers.
Emergency legislation, introduced Tuesday in Congress, promises five paid sick days to those who are sick at work and are sent home by their employers.
But experts are lukewarm that the bill, if passed, would be effective at stopping the spread of H1N1, noting that despite being sent home, a sick person in a work environment for any period of time can spread infection.
And Field said such legislation could have a paradoxical effect, inducing a sick worker to come to work to be sent home with pay rather than stay home in the first place without pay.
Nor is Kernaghan impressed with the bill.
"It might help low-wage workers or workers at near minimum wage," he told ABCNews.com, adding that Walmart employees typically earn above minimum wage. "But I'm not sure it will help Walmart workers. Managers are not going to tell workers to go home sick because they tell them to come into work sick."
Regardless of company policies on sick leave or attendance, for some, the drive to move forward with work and earn a paycheck can override the need to protect oneself or others from infection.
"People make choices that defeat good policy," Casman of Carnegie Mellon said. "It makes it difficult to legislate communicable disease."
But, as part of public health efforts to combat what has proved to be a persistent, if relatively mild, virus, some say rigid employee policies deserve a second look.