Yellow fever, known historically as yellow jack or yellow plague, has plagued humans for centuries. It was widely feared during the 18th and 19th centuries as it was considered one of the world’s most dangerous infectious diseases. Originating in East or Central Africa, it is believed to have spread to the Americas through slave trade. In fact, Brazil suffered its first outbreak in the city Recife as early as 1685. Today it is less feared, but still deserves a healthy dose of respect.

What is Yellow Fever?

Yellow fever is an acute viral haemorrhagic diseaseThe disease is caused by the yellow fever virus and is spread by the bite of female mosquitos of the Aedes and Haemogogus species. The “yellow” refers to the jaundice that affects some patients. The disease can be very dangerous in some instances, even leading to death. 


Symptoms take 3–6 days to develop. Some who get infected will not experience symptoms, but others experience flu-like symptoms including fever, chills, headache, nausea, vomiting, backache and muscle aches. The symptoms in these cases typically last 3-4 days. However, some 15% enter a second, more toxic phase which causes jaundice due to hepatitis (liver damage). 

Patients also typically develop recurring fever, abdominal pain, and bleeding. Death occurs in 20-50% of those entering the second phase.

What is your risk?

Yellow fever is considered a risk in large parts of Brazil. However, in states and cities along the eastern coast the risk is low and vaccination is generally not needed, this includes Rio de Janeiro and São Paulo. All travelers are however recommended to consult a doctor before traveling and review their travel plans.

In states and cities along the eastern coast the risk is low and vaccination is generally not needed, this includes Rio de Janeiro and São Paulo

How can you avoid Yellow fever?

Travellers can protect themselves from yellow fever by getting yellow fever vaccine and by preventing mosquito bites. People can prevent mosquito bites by wearing clothing that fully covers the skin, using mosquito netting while resting, and/or the application of insect repellent (DEET being the most effective).


Yellow fever can be prevented by vaccination. The vaccine is considered extremely effective, safe and affordable. 

Note that:

  • The vaccine protects for 10 years after one injection.
  • Because the vaccine is a live virus, persons with compromised immune systems should not be vaccinated.
  • Persons over the age of 70 who have not previously been vaccinated might have an increased risk of complications.
  • Pregnant women and children under 1 year of age should not be vaccinated.
  • The vaccine contains small amounts of egg proteins, and persons suffering from egg allergy should not be vaccinated.

There is no special treatment available if infected, only supportive treatment. There is no specific antiviral drugs available.


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