Vaccines

Yellow fever
An official yellow fever vaccination certificate may be required depending on your itinerary, plus being protected by the yellow fever vaccine is usually recommended if you'll be traveling outside of urban areas in regions where there is risk of yellow fever transmission.
Requirement: A yellow fever vaccination certificate is required for travelers over 9 months of age coming from countries with infected areas.
International health authorities consider Brazil to be a yellow fever "infected" country because human cases of the disease have been reported in these states: Amapa, Amazonas, Bahia, Goias, Maranhao, Mato Grosso, Minas Gerais, Para, Roraima, Sao Paulo, Tocantins. Authorities also consider it "endemic" because the potential for disease transmission exists in areas that may not currently report human cases.

Malaria
Determine whether you'll be at risk for malaria and what preventive medicine you should take if you are.

• High risk exists throughout the year in the Legal Amazonia region: Acre, Amapa, Amazonas, Maranhao (western part), Mato Grosso (northern part), Pará (except Belem City), Rondonia, Roraima, and Tocantins. Risk is highest in mining and newly settled areas which have > 50% P. falciparum. Some risk exists in cities and towns such as Cuiaba, Rio Branco, Manaus, Boa Vista, Macapa, Santarem, Maraba, and Porto Velho. Travelers on the trans-Amazon highway and on Amazon cruises are at risk. No risk exists in coastal states from the horn to the Uruguay border, Iguassu Falls, and other major tourist and business destinations (Sao Paulo, Rio de Janeiro, Salvador, Recife, Fortaleza, and Porto Alegre).
  
• Medicines that protect against malaria in this area include mefloquine (Lariam), doxycycline, or atovaquone/proguanil (Malarone). The best drug for you depends on your itinerary and on a number of personal factors that should be discussed between you and your health care provider.
  
• Because no malaria drug is 100% effective, if you have traveled in an area of malaria risk, seek immediate medical attention for any fever or flu-like illness occurring within 3 months of your return home. Be sure to tell your health care provider your travel history.
  

Other vaccines
Depending on your itinerary, your personal risk factors, and the length of your visit, your health care provider may offer you vaccination against hepatitis A, typhoid, hepatitis B, rabies, or influenza. Routine immunizations, such as those that prevent tetanus/diphtheria or "childhood" diseases, should be reviewed and updated as needed.