Annie Grant, 55, had been feverish for two nights. Worried about the coronavirus outbreak, her adult children had begged her to stay home rather than return to the frigid poultry plant in Georgia where she had been on the packing line for nearly 15 years.

But on the third day she was ill, they got a text from their mother. “They told me I had to come back to work,” it said.

Ms. Grant ended up returning home, and died in a hospital on Thursday morning after fighting for her life on a ventilator for more than a week. Two other workers at the Tyson Foods poultry plant where she worked in Camilla, Ga., have also died in recent days.