A Yellow Fever vaccination certificate is only required for travellers 1 year of age and older coming from Brazil, including travellers who transit for more than 12 hours through an airport in Brazil.
The vaccination requirement is imposed by this country for protection against Yellow Fever since the principal mosquito vector Aedes aegypti is present in its territory.
For your protection, Yellow Fever vaccination is recommended for all travellers 9 months of age and older travelling at altitudes below 2300 m / 7,546 ft, including Angel Falls.
Note: Vaccination is not recommended if only travelling to the Distrito Federal and the states of Vargas, Miranda, Aragua, Carabobo, and Yaracuy. Take meticulous anti-mosquito bite measures during the daytime in these areas. Margarita Island, Caracas and Valencia, the states of Falcón and Lara are risk free.
Countries may change their vaccination requirements without notice and in some instances border agents use their discretion to deny entry despite the officially stated requirements.
If there is risk of Yellow Fever at your destination, whether vaccination is required for entry or not, be prepared to show a certificate of vaccination or a waiver stating the medical reasons for not being vaccinated.