In The Reshaping of Everyday Life: 1790–1840, Jack Larkin shows that yellow fever replaced smallpox as the deadliest and most feared disease in America by the 1830s. At the end of the eighteenth century, Edward Jenner developed the smallpox vaccine, and kinepox became known as an effective method of inoculation against smallpox. Lewis and Clark carried kinepox on their expedition, at the suggestion of Thomas Jefferson. At the same time, yellow fever, which was not endemic to the United States, appeared in several port cities and killed thousands of people. In 1793, Philadelphia lost nearly 10% of its population to an epidemic of yellow fever, and many more fled the city, creating widespread panic.