YELLOW FEVER VACCINE
The 17D vaccine, which is based on a live, attenuated viral strain, is the only commercially available
yellow fever vaccine. It is given as a single subcutaneous (or intramuscular) injection. Yellow fever
vaccine is highly effective (approaching 100%). All individuals aged 9 months or older and living in
countries or areas at risk should receive yellow fever vaccine.
[5] With the exception of very rare cases of vaccine-associated neurotropic and viscerotropic disease
(see below), the 17D vaccine is generally considered to be safe. Contraindications include severe
hypersensitivity to egg antigens and severe immunodeficiency. […] Noting that yellow fever vaccine is
a live vaccine, a risk-benefit assessment should be undertaken for all pregnant and lactating women. In
areas where YF1 is endemic, or during outbreaks, the benefits of YF vaccination are likely to far outweigh
[10] the risk of potential transmission of vaccine virus to the fetus or infant. Pregnant women and nursing
mothers should be counselled on the potential benefits and risks of vaccination so that they may
make an informed decision about vaccination. Lactating women should be advised that the benefits
of breastfeeding far outweigh alternatives. Vaccination is recommended, if indicated, for pregnant or
breastfeeding women travelling to endemic areas when such travel cannot be avoided or postponed.
[15] The YF vaccine is contraindicated in infants under 6 months of age and is not recommended for those
aged 6–8 months, except during epidemics when the risk of YF transmission may be very high.
Viscerotropic disease: Vaccine-associated viscerotropic disease is a recently described adverse event
that on very rare occasions has occurred after the first immunization with the yellow fever 17D vaccine.
Onset is within 10 days of vaccination and the pathological process is characterized by severe multi-
[20] organ failure and an overall case–fatality rate in excess of 60%. Known risk factors include a history of
thymus disease (e.g. thymoma or thymectomy) and age ≥60 years. [...]
Neurotropic disease: Increased incidence of vaccine-associated neurotropic disease (e.g.
meningoencephalitis, acute disseminated encephalomyelitis and Guillain–Barré syndrome) has been
reported in infants under 6 months of age and in vaccine recipients aged 60 years and older. [...]
[25] Yellow fever vaccination is required for travellers to certain countries and is recommended for all
travellers to countries or areas with risk of yellow fever transmission […] While yellow fever vaccination
should be encouraged as a key prevention strategy, it is important to screen travel itineraries and
carefully evaluate the potential risk of systemic illness after yellow fever vaccination. Great care should
be exercised not to prescribe yellow fever vaccination to individuals who are not at risk of exposure to
[30] infection, based on an accurate assessment of the travel itinerary. Although vaccination is generally not
recommended for travellers going to areas where the risk of exposure is low, any risk (e.g. as a result of
prolonged travel or heavy exposure to mosquito bites) should be weighed against individual risk factors
for vaccineassociated adverse events (e.g. altered immune status).
Adaptado de who.int/ith/vaccines/yf/en/, 11/03/2018.
1 YF - yellow fever
It is important to screen travel itineraries and carefully evaluate the potential risk of systemic illness after yellow fever vaccination. (l. 27-28)
The fragment above ⟹ that the travel itineraries have to be
