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
Yellow fever vaccine within 2 to 5 days of the vaccine in 1996–2001, 6 died "including 2 who were vaccinated even though they were planning to travel to countries where yellow fever has never been reported." The article cites that "3 demonstrated histopatholic changes consistent with wild yellow fever virus." The author recommends vaccination for only non-contraindicated travelers (see the articles list) and those travelers going where yellow fever activity is reported or in the endemic zone which can be found mapped at the CDC website cited below. In addition, the 2010 online edition of the Center for Disease Control Traveler's Health Yellow