The Dutch Vaccine — book cover. A woman in 19th-century dress walks toward a lantern-lit Amsterdam mansion at night.
September 2026

A Jack Thomas Thriller

The Dutch Vaccine

Introducing Elsa Hagen

A cure worth killing for.

For readers of Frieda McFadden and Gillian Flynn.

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“He poisoned me. And soon he will kill me.”

Netherlands, 1883. A vaccine doctor is dead. His fiancée is missing. She is Elsa Hagen's sister. And the men who killed him have decided Elsa knows too much to live.

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I'm Jack Thomas. I write historical thrillers from the Netherlands. The Dutch Vaccine is book one of the Elsa Hagen series. Fast, claustrophobic, and set in 1883 Leiden. The wrong question can get you killed.

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