Brazil Launches World’s Largest Vaccination Campaign to Stem Rise of Yellow Fever




ellow fever is a potentially deadly viral hemorrhagic disease transmitted by infected mosquitoes, and endemic in tropical areas of Africa and Central and South America.


In response to a deadly outbreak of yellow fever, Brazil launched a mass immunization campaign on January 25, 2018, to deliver fractional doses of yellow fever vaccine to 23.8 million residents. The strategic plan for the campaign was developed with support from the Pan American Health Organization (PAHO) and the World Health Organization (WHO).


Fractional dosing, also known as dose-sparing, is a way to extend vaccine supplies, protecting more people and reducing the possibility of disease spread. One-fifth of the regular dose of yellow fever vaccine still provides immunity against the disease for at least 12 months and likely longer. The use of fractional doses of yellow fever vaccine is not recommended as a long-term strategy or to replace routine immunization practices. The full yellow fever vaccine provides up to 99% lifetime immunity.


WiRED International offers a health education module on yellow fever. The module includes the infection’s description, its means of transmission, signs and symptoms, diagnosis, laboratory evaluation and treatment, as well as technical guidelines for health professionals. As always, WiRED stresses prevention, which, in this case, includes vaccination, wearing protective clothing, using insect repellent and controlling mosquito vectors. WiRED also features a Mosquito webpage.


As always, WiRED stresses prevention, which, in this case, includes vaccination, wearing protective clothing, using insect repellent and controlling mosquito vectors.

Health officials are urging travelers headed to Brazil to get yellow fever vaccinations. The Brazilian Ministry of Health said that since July 1, a total of 53 people have died in Brazil after contracting the disease.


WiRED believes that the key to containing any outbreak is for health professionals and general populations to be prepared and educated about disease health risks and prevention.






Sample Quiz from WiRED’s Yellow Fever Module

1. Yellow fever principally affects humans and ____________.

 Pigs  Monkeys  Dogs  Birds

2. Most people improve within ________ after the symptoms of yellow fever first appear.

 2 to 3 days  3 to 4 days  1 week  10 days

3. ______________ can sometimes detect the virus in the early stages of the disease.

 Urinalysis  Sputum samples  Blood tests


What Is Yellow Fever?


Yellow fever is an acute viral hemorrhagic disease, and, like Zika, it is transmitted to humans by infected Aedes aegypti mosquitoes. Yellow fever occurs in tropical and subtropical areas of Africa and the Americas. The “yellow” in the name refers to the jaundice that affects some patients. (Jaundice causes the skin and other body tissues to turn yellow.) The illness can range in severity from a fever to severe liver disease with bleeding. About 15% of people who get yellow fever become ill enough to experience bleeding, shock, organ failure and sometimes death.



The History of Yellow Fever


1000 B.C. Scientists believe yellow fever originated in Africa at least 3,000 years ago.
1600s Yellow fever traveled to the western hemisphere on slave ships from West Africa.
1648 Mayan manuscripts provided the first recorded evidence of the disease.
1700s Yellow fever spread from the Americas to Europe.
Late 1800s Scientists realized that the illness was spread by mosquitoes and not by direct contact with infected individuals or contaminated objects.
1898 Ongoing outbreaks prompted the creation of The Reed Yellow Fever Commission, led by American army surgeon Walter Reed. The Commission proved that the Aedes aegypti mosquito transmitted yellow fever to humans.
1906 The building of the Panama Canal had been severely hampered by the yellow fever infection in workers. Stringent sanitation programs stopped the outbreaks and enabled completion of the Panama Canal.
1930 Two vaccines for yellow fever were developed: the French neurotropic vaccine and the 17D vaccine, which is the one used today.
1950s Yellow fever cases started to appear in Africa and the Americas where vaccine coverage had disappeared or been discontinued.
1980s Outbreaks in Africa swelled to 120,000 cases and 24,000 deaths. Vaccine coverage was poor or nonexistent.
2000s Today there are still far too many people, particularly in Africa, who do not receive the vaccine, and vaccine shortages occur. Hundreds of cases of yellow fever from endemic countries in South America and Africa are still reported annually to the World Health Organization, which estimates that unreported cases number in the thousands.


Source: CDC





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