Roald Dahl’s daughter who died from measles encephalitis was Olivia.
Olivia Dahl died in 1962 at the age of seven after developing measles encephalitis, an inflammation of the brain associated with measles infection. Her death had a profound effect on Dahl and later influenced his support for childhood vaccination.
Dahl wrote an open letter about the tragedy, urging parents to protect children through vaccination. The letter became especially notable because it combined a personal family loss with a public-health argument. It is often cited as an example of his advocacy outside literature.
Olivia is sometimes confused with Dahl’s other daughters, Tessa and Lucy, or with his daughter Ophelia, who later became involved in health and charitable work. The family included five children in total, but Olivia was the child who died from measles encephalitis.