Dahl was born on 20 April 1955 at Doctors Hospital in New York City [1] and grew up in the Buckinghamshire village of Great Missenden.
Her middle name, Twenty, originated from the date of her birth, and the fact that her father had $20 in his pocket when he saw her in the hospital for the first time.
[2] Neal "struggled" with Olivia shortly after her birth but found her behaviour transformed after spending a few weeks with her paternal aunt, Elsie Logsdail.
Neal contacted her brother-in-law, Ashley Miles, who sent them gamma globulin, then common in the United States, to boost children's immunity against measles.
[3] Olivia subsequently contracted measles, and had a mild fever for a few days before suffering convulsions after growing increasingly lethargic.
[7] Roald Dahl became increasingly depressed and withdrawn after Olivia's death, spending hours at her grave in silence.
He later became a vaccination advocate, writing an account of Olivia's death in a 1986 pamphlet titled "Measles: a dangerous illness" for the Sandwell Health Authority.
Then one morning, when she was well on the road to recovery, I was sitting on her bed showing her how to fashion little animals out of coloured pipe cleaners, and when it came to her turn to make one herself, I noticed that her fingers and her mind were not working together and she couldn't do anything.
[13] Olivia's sister, Lucy, interviewed in 2015 by CBS, stated that her father did not understand why people chose not to vaccinate their children against measles.