1. An international certificate of vaccination against polio is compulsory for children aged between three months and six years.

2. An international certificate of vaccination against yellow fever is compulsory for travelers who, within three months prior to their arrival in Brazil, have visited or been in transit through the following countries:
   Angola, Benin, Bolivia, Burkina Faso, Cameroon, Colombia, the Democratic Republic of Congo, Ecuador, French Guyana, Gabon, Gambia, Ghana, Guinea Bissau, Liberia, Malta, Nigeria, Peru, Sierra Leone, Sudan, Venezuela and Zaire.

3. Additionally, vaccination against yellow fever is recommended for all travelers when visiting the following states of Brazil:
   Acre, Amazonas, Amap�, Distrito Federal, Goi�s, Maranh�o, Mato Grosso do Sul, Par�, Rond�nia, Roraima and Tocantins.

Please note that yellow fever vaccinations take approximately 10 days to become effective.