Clara Maass

American nurse

The death of a twenty-five-year-old nurse in 1901 effectively ended the practice of human experimentation in yellow fever research. Clara Maass, a graduate of the Newark German Hospital’s nursing school, died in Havana after volunteering for a series of medical tests designed to determine if the Culex fasciata mosquito was the primary vector for the disease.

Early Career and Army Service

Born in 1876 in East Orange, New Jersey, Maass was the oldest of ten children in a Lutheran family. Following her graduation in 1895, she worked as a head nurse at Newark German Hospital. During the Spanish-American War, she served as a contract nurse in the Seventh U.S. Army Corps, stationed in Florida, Georgia, and Cuba. Later, she served with the Eighth U.S. Army Corps in the Philippines, frequently treating patients suffering from malaria, typhoid, and dengue fever.

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Yellow Fever Research in Cuba

In October 1900, Maass returned to Cuba at the request of Major General William C. Gorgas, who worked with the U.S. Army’s Yellow Fever Commission. Led by Major Walter Reed, the commission investigated the transmission of yellow fever. Maass became one of nineteen human volunteers—and the only female—to participate in mosquito-bite experiments. Participants received payment for their service, with additional compensation provided if they contracted the illness.

Experimentation and Death

Between March and August 1901, Maass was bitten by infected mosquitoes on seven separate occasions. Researchers hoped to demonstrate that surviving an earlier, milder case of the fever would provide immunity. This hypothesis proved incorrect. Maass fell ill on August 18, 1901, and died six days later in Havana. Her death prompted a public outcry and the immediate cessation of human trials in the yellow fever program.

Commemoration

Initially buried in Havana, her remains were moved to Fairmount Cemetery in Newark in 1902. In 1952, the Newark German Hospital was renamed the Clara Maass Memorial Hospital, later becoming the Clara Maass Medical Center. She was featured on a 1976 United States postage stamp, the first nurse to receive such recognition, and was inducted into the New Jersey Hall of Fame in 2017.

Fast facts

Questions readers ask

Why did Clara Maass volunteer for the experiments?

Motives remain unclear, with historians citing potential factors including financial support for her family, a desire to gain immunity, or a humanitarian commitment to medical research.

What was the result of her sacrifice?

Her death led to the termination of human experimentation for yellow fever research and ultimately contributed to the development of a vaccine for the disease.

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