The book was published by Beijing Science and Technology Press in February, and the e-book was translated into English by 21st Century English Education Media.

"The photo is so heart-wrenching, especially for mothers," says Wu about the original idea for the book. She lives in Beijing and runs a WeChat media account, Diguagua Planet, with five mothers, that features topics related to parenting and education.

"Seeing so many photos capture the farewell scenes happening across the country, as a mother I felt what they felt, I couldn't help but cry, and then I wanted to write something for those kids," Wu says.

More than 32,000 medical workers from across the country were working in Hubei as of Feb 17.

Wu notices that there are already some books on the shelf about what the novel coronavirus is and virus prevention measures, which answer people's need for facts.