14 Jun 2016

Infants under 9 months of age

The risk of yellow fever vaccine-associated encephalitis is higher in infants under nine months of age Infants under 9 months of age
Image provided by NHS Photo Library


The risk of yellow fever (YF) vaccine-associated encephalitis is higher in infants under nine months of age [1]. The risk is inversely proportional to age (highest risk for the youngest infants) [1-3]. During the 1950’s, when there was no age restriction on the use of the YF vaccine, 15 cases of encephalitis were reported in infants. Of the 15 cases, 13 (87%) occurred in infants under four months of age and all were under seven months of age (age was not documented in the remaining two cases) [2]. The vaccine should therefore never be administered to infants under six months of age [1, 2].

Infants aged six to nine months should only be immunised if the risk of YF during travel is unavoidable; expert opinion should be sought in these situations [1]. For this age group, vaccination is usually only recommended during epidemics / outbreaks when the risk of YF virus transmission may be very high [see TravelHealthPro Country Information Pages].

Individual itineraries should be considered on a case by case basis, and if possible, travel should be delayed until the infant is 9 months of age [2].  

When travel is unavoidable, and YF vaccine is not an option, particular care with insect bite avoidance day and night should be recommended.  

Very young children (aged less than 2 years) may have suboptimal sero-conversion rates following a single dose of the vaccine and may, therefore, benefit from a single booster dose 10 years after the original dose [1, 4].

Off-site administration

Off-site administration policy for designated Yellow Fever Vaccination Centres (YFVCs) in England, Wales and Northern Ireland Read more

Individuals aged 60 years and older

Age alone is not considered a contraindication to YF vaccination, and vaccination can be given to those aged 60 years and older following risk assessm Read more

People living with HIV

Live vaccinations are contraindicated in individuals with immunosuppression due to human immunodeficiency virus (HIV) infection Read more

Febrile illness

General vaccine guidance from Public Health England states that minor illnesses without fever or systemic upset are not valid reasons to postpone immu Read more
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