The eradication of yellow fever strengthened the relationship between the US and Mexico, which had not been very good in the years prior. The eradication of yellow fever was also a major step toward better global health.In 1927, scientists isolated the yellow fever virus in West Africa. Following this, two vaccines were developed in the 1930s. Max Theiler led the completion of the 17D yellow fever vaccine in 1937, for which he was subsequently awarded the Nobel Prize in Physiology or Medicine. That vaccine, 17D, is still in use, although newer vaccines, based on vero cells, are in development (as of 2018). Current status
Using vector control and strict vaccination programs, the urban cycle of yellow fever was nearly eradicated from South America. Since 1943, only a single urban outbreak in Santa Cruz de la Sierra, Bolivia, has occurred. Since the 1980s, however, the number of yellow fever cases has been increasing again, and A. aegypti has returned to the urban centers of South America. This is partly due to limitations on available insecticides, as well as habitat dislocations caused by climate change. It is also because the vector control program was abandoned. Although no new urban cycle has yet been established, scientists believe this could happen again at any point. An outbreak in Paraguay in 2008 was thought to be urban in nature, but this ultimately proved not to be the case.In Africa, virus eradication programs have mostly relied upon vaccination.
Mosquitoes may bite through thin clothing, so spraying clothes with repellent containing permethrin or another EPA-registered repellent gives extra protection. Clothing treated with permethrin is commercially available. Mosquito repellents containing permethrin are not approved for application directly to the skin. The peak biting times for many mosquito species are dusk to dawn. However, A. aegypti, one of the mosquitoes that transmits yellow fever virus, feeds during the daytime. Staying in accommodations with screened or air-conditioned rooms, particularly during peak biting times, also reduces the risk of mosquito bites. Vaccination
Vaccination is recommended for those traveling to affected areas, because non-native people tend to develop more severe illness when infected. Protection begins by the 10th day after vaccine administration in 95% of people, and had been reported to last for at least 10 years. The World Health Organization (WHO) now states that a single dose of vaccine is sufficient to confer lifelong immunity against yellow fever disease. The attenuated live vaccine stem 17D was developed in 1937 by Max Theiler. The WHO recommends routine vaccination for people living in affected areas between the 9th and 12th month after birth.Up to one in four people experience fever, aches, and local soreness and redness at the site of injection. In rare cases (less than one in 200,000 to 300,000), the vaccination can cause yellow fever vaccine-associated viscerotropic disease, which is fatal in 60% of cases. It is probably due to the genetic morphology of the immune system.