Germs: A Virus to Survive by David Walliams. Ages 7+.
Germs: A Virus to Survive (2020) is a highly inventive comedy told from the perspective of GERM, a tiny virus living inside a boy named Alfie. As GERM navigates the human body, encounters other viruses and tries to survive as the immune system hunts it down, readers learn how viruses work, how the body fights infection, and how the immune system operates.
The novel is both genuinely educational and very funny. Walliams uses an unusual point of view to make biology accessible and memorable.