1793 Philadelphia yellow fever epidemic with slaves, arrived from Cap Français, Saint-Domingue. The 2,000 immigrants were fleeing the slave revolution in the north of the island. They crowded the port of Philadelphia, where the first yellow fever epidemic in 30 years began in the city in August. It is likely that the refugees and ships carried the yellow fever virus and mosquitoes. It is transmitted during mosquito bites. The mosquitoes easily breed in small amounts of standing water. The medical community and others in 1793 did not understand the role of mosquitoes in the transmission of yellow fever and other diseases. Physicians and other survivors
Yellow fever vaccine of age. Those travelling to areas where the disease occurs should also be immunized. Additional doses after the first are generally not needed. Yellow fever vaccine is generally safe. This includes in those with HIV infection but without symptoms. Mild side effects may include headache, muscle pains, pain at the injection site, fever, and rash. Severe allergies occur in about eight per million doses, serious neurological problems occur in about four per million doses, and organ failure occurs in about three per million doses. It is likely safe in pregnancy and therefore recommended among those who will be potentially exposed.