YELLOW FEVER VACCINE



Indications

– Prevention of yellow fever:
• in children from 9 months of age and adults living in or travelling to or from endemic areas
• in mass immunisation campaigns in the event of an outbreak

Composition, forms, route of administration

– Live-attenuated virus vaccine, prepared by culturing the virus in embryonated chicken eggs
– Powder for injection in monodose and multidose vials, to be dissolved with the entire vial of diluent supplied by the manufacturer, for IM injection into the anterolateral part of the thigh in children < 2 years and into the deltoid muscle in children ≥ 2 years and adults

Dosage and vaccination schedule

– Child and adult: 0.5 ml single dose
– In routine immunisation (EPI), the vaccine is usually administered between 9 and 12 months of age, along with the measles vaccine.
– Vaccination is contra-indicated in children less than 6 months. In children between 6 and 9 months, vaccination is only recommended in epidemics, as the risk of virus transmission may be very high.

Contra-indications, adverse effects, precautions

– Do not administer to patients with history of allergy to egg; to immunocompromised patients or patients with symptomatic HIV infection or under immunosuppressive treatment.
– Vaccination should be postponed in the event of severe acute febrile illness; minor infections are not contra-indications.
– May cause: mild reactions at the injection site (redness, pain at the injection site), mild fever, headache, myalgia; rarely: hypersensitivity reactions, neurological disorders (especially in children < 9 months and adults > 60 years), multiple organ failure (especially in adults > 60 years).
– If administered simultaneously with other vaccines, use different syringes and injection sites.
– Pregnancy: not recommended. However, given the severity of yellow fever, the vaccine is administered when the risk of contamination is very high (epidemics, unavoidable travel to regions of high endemicity).
– Breast-feeding: no contra-indication

Remarks

– A standard 0.5 ml single dose by IM injection is sufficient to confer life-long immunity. A booster dose is no longer recommended.
– Only in the event of limited vaccine supply during yellow fever outbreaks and according to national recommendations, vaccination may be administered by SC or IM injection in children over 2 years and adults with a fractional dose of 1/2 or 1/5 of the standard dose (minimum 0.1 ml) using vials containing a maximum of 10 standard doses. Children < 2 years, pregnant women and HIV positive individuals are administered a standard 0.5 ml dose by IM injection.
– Storage
• Powder: between 2 °C and 8 °C.
• 
Diluent: a cold chain is not required for storage. However, at least 12 hours before reconstitution of the vaccine, the diluent must be refrigerated between 2 °C and 8 °C so that the diluent and lyophilised powder are at the same temperature: a temperature difference during reconstitution may reduce vaccine efficacy. Do not freeze.
• 
Reconstituted vaccine: between 2 °C and 8 °C, for 6 hours maximum.