7h 56min, may 15, 1832 y - Indian Vaccination Act
Description:
 Congress enacted the first piece of federal legislation designed to deal with a specifically American Indian health problem, epidemic smallpox. 
This legislation enabled the federal government to vaccinate around forty to fifty thousand American Indians. These vaccinations were used to enable Indian removal and relocation to reservations. 
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Date:
7h 56min, may 15, 1832 y
Now
 ~ 193 years ago