One of the big issues with Typhoid Mary was that she continued to work as a cook. As soon as she was busted, she went somewhere else and got a job as a cook.The fact that she infected at least 53 people and killed at least 3. might also have had something to do with her being quarantined.

Mary Mallon (September 23, 1869 - November 11, 1938), also known as Typhoid Mary, was an Irish-born cook believed to have infected 53 people with typhoid fever, three of whom died, and the first person in the United States identified as an asymptomatic carrier of the disease pathogen, Salmonella typhi.Because she persisted in working as a cook, by which she exposed others to the disease, she was twice forcibly quarantined by authorities, eventually for the final two decades of her life. Mallon died after a total of nearly 30 years in isolation.

en.wikipedia.org