Yellow fever Brazil. In March 2018, Brazil shifted its policy and announced it planned to vaccinate all 77.5 million currently-unvaccinated citizens by April 2019. Some countries in Asia are theoretically in danger of yellow fever epidemics (mosquitoes with the capability to transmit yellow fever and susceptible monkeys are present), although the disease does not yet occur there. To prevent introduction of the virus, some countries demand previous vaccination of foreign visitors if they have passed through yellow fever areas. Vaccination has to be proved by the production of a vaccination certificate which is valid 10 days after the vaccination and lasts for
1793 Philadelphia yellow fever epidemic authorized. After an extensive debate in the newspapers, the State Assembly denied the petition. The recurrences of yellow fever kept discussions about causes, treatment and prevention going until the end of decade. Other major ports also had epidemics, beginning with Baltimore in 1794, New York in 1795 and 1798, and Wilmington in 1798, making yellow fever a national crisis. New York doctors finally admitted that they had had an outbreak of yellow fever in 1791 that killed more than 100 people. All the cities that suffered epidemics continued to grow rapidly. The widespread recognition that the epidemics were based along