Yellow Fever

Question 1

What type of vaccine is the yellow fever vaccine?

Answer 1

Live attenuated yellow fever virus grown in chicken eggs

Question 2

For whom is the yellow fever vaccine recommended? (3)

Answer 2

1. Laboratory workers handling infected materials
2. Individuals aged 9 mo or older who are travelling to or living in areas where there is a risk of yellow fever transmission
3. Individuals aged 9 mo or older who are travelling to, or living in countries that require an International Certificate of Vaccination or Prophylaxis (ICVP) for entry

Question 3

Why is the yellow fever vaccine not recommended for children under 9 mo?

Answer 3

The associated risk of vaccine-associated encephalitis is higher, with the risk being inversely proportional to age

Children under 6 mo should NOT be vaccinated

Children 6-9 mo should only be vaccinated following a detailed risk assessment and if the risk of transmission is high (such as during outbreaks)

Question 4

Can the yellow fever vaccine be given to immunocompromised or immunosuppressed individuals?

Answer 4

No, because it is a live vaccine, it should be avoided in these patient populations

If the yellow fever risk is unavoidable in HIV-infected individuals, consult specialist advice

Question 5

What is the primary vaccination regimen for the yellow fever vaccine?

Answer 5

A single dose confers life-long immunity

Immunisation should be performed at least 10 days before travelling to an endemic area

Reinforcing immunisation is not needed, except for a small subset of individuals at continued risk who may not have developed long-term protection from their initial vaccine

Question 6

Is a yellow fever vaccine booster available?

Answer 6

No, reinforcing immunisation is not needed, except for a small subset of individuals at continued risk who may not have developed long-term protection from their initial vaccine

Question 7

Is yellow fever a notifiable disease?

Answer 7

Yes, all suspected cases must be notified to the local heath protection unit

Question 8

What organism causes yellow fever?

Answer 8

Yellow fever virus, an arbovirus of the flavivirus genus

Question 9

How is yellow fever transmitted?

Answer 9

Yellow fever is an arbovirus (arthropod borne virus), meaning it is transmitted by insects, specifically mosquitos (Aedes and Haemogogus)

Question 10

What are the symptoms of the acute phase of yellow fever?

Answer 10

ACUTE PHASE:
Fever
Headache
N/V
Myalgia
Photophobia 
Anorexia 
Red eyes, face, or tongue

Question 11

What are the symptoms of the toxic phase of yellow fever?

Answer 11

TOXIC PHASE: more severe and life-threatening

• yellowing of the skin and sclera
• abdominal pain
• hematemesis
• oliguria
• epistaxis
• bradycardia
• liver failure
• kidney failure
• encephalitis

(Death in 20-50% of cases of severe disease)

Question 12

In which areas is yellow fever endemic? (2)

Answer 12

Sub-Saharan Africa

Tropical South America