What is yellow fever?

Yellow fever is a viral infection caused by flavivirus transmitted to humans from the bite of a mosquito carrying the virus.

The yellow fever virus is found in tropical and subtropical areas of Africa and South America.

The disease cannot be spread from one person to another.

Yellow fever is a viral hemorrhagic disease. Yellow fever may present with mild symptoms and signs ranging from fever, aches and pains, headache, to severe liver disease with bleeding from the mouth, ear, or nose, yellowing of skin (jaundice) and yellow eyes (jaundice). Severe complications are not common; a small proportion of patients who contract the virus develop severe symptoms and approximately half of those die within 7 to 10 days.

Yellow fever infection is diagnosed based on laboratory testing, a person’s symptoms, exposure and travel history.

How is yellow fever treated?

There is no medicine to treat or cure the infection. Treatment involves managing symptoms and assisting your immune system in fighting off the infection by:

  • getting enough fluids, possibly by intravenous drip
  • getting oxygen
  •  maintaining a healthy blood pressure
  •  getting blood transfusions
  • having dialysis if you experience kidney failure
  • getting treatment for other infections that may develop

How to prevent yellow fever

Vaccination remains the most effective form of prevention with yellow fever vaccine: This safe and effective yellow fever vaccine has been available for more than 80 years. It is a live vaccine and should not be given to the following people:

  • people who have severe allergies to eggs, chicken proteins, or gelatin
  • infants younger than 9 months old
  • people who have HIV, AIDS, or other conditions that compromise the immune system

Other vaccine considerations: Some people may have an increased risk of developing a reaction to the vaccine, but may still benefit from being vaccinated. These people, or their guardians, should talk to their doctor about getting vaccinated:

  • Between 6 and 8 months old
  • Over 60 years old
  • Pregnant
  • Breastfeeding

A single dose of yellow fever vaccine provides lifelong protection for most people. A booster dose is not required except in travelers going to areas with an outbreak, may consider getting a booster dose of vaccine if it has been 10 years since their last yellow fever vaccine.

The vaccine provides effective immunity within 10 days for 80-100% of people vaccinated, and within 30 days for more than 99% of people vaccinated.

What are the ways to prevent mosquito bite?

To prevent mosquito bite



  • Wear long-sleeved shirts and long pants


  • Prevent mosquito breeding site by keeping water containers covered and by clearing gutters and getting rid of pools of stagnant water.


Resources: For suspected cases of yellow fever in Nigeria report to the nearest health facility. Contact NCDC toll free 0800-970000-10


Photo by Егор Камелев on Unsplash





Compiled by Dr. Ngozi Onuoha

To share this post