These days, Chloe Chang, a Taiwanese woman stranded at the center of China’s coronavirus outbreak, says she wakes up every half-hour during the night. Sometimes she breaks down in tears.

She and her family are effectively trapped in her grandmother’s apartment building, where a man recently died from the virus. Workers in hazmat suits haunt the surrounding streets, and the neighborhood has a strong police presence. There are shortages of food and other essentials throughout Yichang, the Hubei Province city of more than four million where they have been in limbo for weeks.

“No household can go out at this time,” said Ms. Chang, a 26-year-old industrial artist. She said she feared that even a trip for groceries would increase her chances of contracting the virus.

“My child has eaten nine meals of plain noodles in the past three days,” she said of her 2-year-old son.