World A letter from Catherine the Great urged mass immunization in 1787. It just sold for over $1 million. December 2, 2021 Scott Gleeson, USA TODAY Comments Off on A letter from Catherine the Great urged mass immunization in 1787. It just sold for over $1 million. After being immunized against smallpox twenty years earlier, Catherine the Great showed the "statecraft and foresight shown by the great monarch."