What is Yellow Fever?
Yellow fever is a disease caused by a virus that is spread through certain mosquito (aedes aegypti) bites. The infection is common in areas of Africa and South America.
Signs and Symptoms
Acute phase:
- Fever
- Headache
- Muscle aches (primarily back and knees)
- Sensitivity to light
- Nausea
- Vomiting
- Decreased appetite
- Dizziness
- Red eyes, face, and tongue
Toxic Phase:
- Jaundice (yellowing of the skin, eyes)
- Abdominal pain
- Vomiting, sometimes with blood
- Decrease urination
- Bleeding from nose, mouth, and eyes
- Liver and kidney failure
- Brain dysfunction including delirium, seizure, and coma
- Death
How does Yellow Fever spread?
The virus spreads when a person is bitten by an infected mosquito. There are three transmission cycles.
- The jungle (sylvatic) cycle is when transmission of the virus occurs between non-human primates (e.g., monkeys) and mosquito species in the forest. The virus is transmitted by mosquitoes from monkeys to humans when humans are visiting or working in the jungle.
- The intermediate (savannah) cycle exists in Africa. In this cycle, the virus can be transmitted from monkey to human or from human to human via mosquitoes. The virus is transmitted from mosquitoes to humans living or working around jungle border areas
- The urban cycle involves the transmission of the virus between humans and urban mosquitoes. The virus is usually brought to the urban setting by an infected person who had visited the jungle or savannah.
What are the complications of Yellow Fever?
- Kidney and liver failure
- Brain dysfunction including delirium, seizure,
- Coma,
- Bleeding
- Death
What is the Yellow Fever Vaccine and how do you prevent it?
Yellow fever vaccine is a vaccine that protects against yellow fever. Yellow fever is a viral infection that occurs in Africa and South America. Most people begin to develop immunity within ten days of vaccination and 99 percent are protected within one month.
In addition to avoiding mosquito bites, the best way is to get vaccinated. Only one yellow fever vaccine (YF-VAX, Sanofi Pasteur) is licensed in the United States currently. This vaccine is a live attenuated vaccine and recommended for ages 9 months and older. The vaccine lasts for lifetime for most people, but booster after 10 years is recommended for certain people traveling to an area where yellow fever is present. The vaccine should be administered at least 10 days before travel although the preferred time frame is 30 days.
Who needs the Yellow Fever Vaccination?
The Yellow Fever vaccine is recommended for:
- Ages 9 months to 59 years old and traveling to or living in areas at risk for yellow fever virus transmission (South America and Africa).
- Proof of yellow fever vaccine may be required for entry into certain countries
Who should not get the Yellow Fever Vaccination?
- Those with a history of acute hypersensitivity reaction to a previous dose of yellow fever vaccine or components of the vaccine.
- Those with thymus disorder associated with abnormal immune cell function
- Infants less than six months
- Those with immunosuppression (symptomatic HIV infection or AIDs, malignant neoplasms, primary immunodeficiencies, transplantation, immunosuppressive or immunomodulatory therapy, and radiation therapy).
- Precautions should be taken when administering yellow fever to those patients with asymptomatic HIV infection with decreased CD4+ value, pregnancy, breastfeeding, 60 years of age, and infants 6 to 8 months old.
