British author Roald Dahl was one of the most beloved storytellers of the 20th century. Known for his whimsical and imaginative children’s books, Dahl served as a fighter pilot in World War II before turning to writing. His works, including Charlie and the Chocolate Factory, Matilda, The BFG, and James and the Giant Peach, are still some of the most popular children’s stories. But Dahl’s life was marked by personal tragedy.

In 1962, Dahl’s daughter Olivia came sick with measles. As the author recalls in a heartbreaking letter, things quickly took a turn for the worse.

A Tragedy and a Breakthrough

“As the illness took its usual course I can remember reading to her often in bed and not feeling particularly alarmed about it. 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. ‘Are you feeling all right?’, I asked her. ‘I feel all sleepy’, she said. In an hour, she was unconscious. In twelve hours she was dead.”

Olivia had developed encephalitis as a complication of measles. There was nothing they could do.

This event tore Dahl apart. He became depressed and withdrawn, spending hours at her grave in silence. His grief affected his relationship with his surviving children and friends. But for all the tragedy, something good came out of this.

At the time, there was no measles vaccine. The first measles vaccine was licensed in the United States in 1963. It was developed by Dr. John F. Enders and his colleagues, one year after Olivia’s tragedy. The vaccine quickly became popular in the US because it was virtually 100% effective. Within 5 years, measles cases in the US dropped by over 90%. But in the UK, things moved much slower.

By the late 1980s, there were over 80,000 measles cases a year in the UK. Dahl was distraught. He spoke to his doctor. “Why do we have so much measles in Britain, when the Americans have virtually got rid of it?” Dahl made efforts to reach policymakers but didn’t have much of an impact. Then, in 1985, Dahl heard a program on the radio about measles vaccine hesitancy in the UK. He contacted the radio channel and offered to write a letter, which he did in 1986. The first part is quoted above, and here is the continuation.

Roald Dahl’s measles letter

“The measles had turned into a terrible thing called measles encephalitis and there was nothing the doctors could do to save her. That was twenty-four years ago in 1962, but even now, if a child with measles happens to develop the same deadly reaction from measles as Olivia did, there would still be nothing the doctors could do to help her.

On the other hand, there is today something that parents can do to make sure that this sort of tragedy does not happen to a child of theirs. They can insist that their child is immunized against measles. I was unable to do that for Olivia in 1962 because in those days a reliable measles vaccine had not been discovered. Today a good and safe vaccine is available to every family and all you have to do is to ask your doctor to administer it.

It is not yet generally accepted that measles can be a dangerous illness. Believe me, it is. In my opinion, parents who now refuse to have their children immunized are putting the lives of those children at risk. In America, where measles immunization is compulsory, measles like smallpox, has been virtually wiped out.

Here in Britain, because so many parents refuse, either out of obstinacy or ignorance or fear, to allow their children to be immunized, we still have a hundred thousand cases of measles every year. Out of those, more than 10,000 will suffer side effects of one kind or another. At least 10,000 will develop ear or chest infections. About 20 will die.

LET THAT SINK IN.

Every year around 20 children will die in Britain from measles.

So what about the risks that your children will run from being immunized?

They are almost non-existent. Listen to this. In a district of around 300,000 people, there will be only one child every 250 years who will develop serious side effects from measles immunization! That is about a million to one chance. I should think there would be more chance of your child choking to death on a chocolate bar than of becoming seriously ill from a measles immunization.

So what on earth are you worrying about? It really is almost a crime to allow your child to go unimmunized.”

The legacy of Dahl’s letter

Roald Dahl’s books James and the Giant Peach (1961) and The BFG (1982) were dedicated to Olivia. But his measles vaccination efforts are perhaps the best legacy he could offer her. The letter was a success and was a significant part of Britain’s immunization campaign.

After Olivia’s death, Dahl had contacted scientists in Britain and the US to discuss measles and its complications. He had an ongoing correspondence that went on for years and was involved in planning a national study for measles. However, once vaccines became available, he thought the problem would largely be erased.

For the most part, he was right. The measles vaccine has almost eradicated the disease. But the vaccine only works if people take it, which is why Dahl was such a fervent supporter of fighting against measles. Despite age and poor health, he did his best to spread the word on why this vaccine can make such a big difference.

It worked.

His letter was republished several times and was a useful communication tool. The letter was carefully crafted, using words like “caught” or “got infected by” rather than “contracted.” Dahl was, above all, a storyteller. He was also later asked to promote the polio vaccine as well.

But vaccine hesitancy is far from over.

Why this is relevant today

Roald Dahl’s letter remains just as important today as it was when he first wrote it. Despite decades of medical advancements and even better vaccines, measles has not been fully eradicated. In fact, cases have been rising in recent years due to declining vaccination rates fueled by misinformation and vaccine hesitancy. We’re faced with a resurgence of measles outbreaks in countries where the disease was once considered under control, especially in the US.

Robert F. Kennedy Jr., a prominent vaccine skeptic, was appointed as the U.S. Secretary of Health and Human Services in February 2025. His history of promoting vaccine misinformation raises important concerns, especially amid a significant measles outbreak in Texas and New Mexico spreading among unvaccinated individuals.

Despite assurances that he would not alter existing vaccination policies, Kennedy has initiated a “review” of the childhood vaccine schedule. The current childhood vaccine schedule has been extensively studied for safety and effectiveness by numerous experts, while Kennedy has repeatedly spread debunked claims about vaccines, including linking them to autism — a theory that has been thoroughly discredited. Given this context, his review is more likely to be politically or ideologically motivated rather than a neutral, evidence-based assessment.

Yet Kennedy is far from the only major source of disinformation. That’s why it’s more important than ever to spread the word on the truths around vaccines and the devastating consequences that vaccine hesitancy can have.

The measles vaccine is safe, effective, and has saved millions of lives. Yet, as long as some parents choose not to vaccinate, outbreaks will continue, putting vulnerable children at risk and causing preventable deaths.

The fight against measles is not over, and Dahl’s advocacy is still relevant. His letter should be shared, read, and remembered — not just as a historical document but as a wake-up call for today’s world. Olivia’s tragedy should be a wake-up call, not something we play on repeat.