In this wide area of information you will get as many different answers as you ask different doctors or institutions for tropic diseases. By the end you have to do what you think is the best for you.
Anyway I guess every traveller to South America should be vaccinated for Tetanus, Hepatitis and Yellow Fever. For a good Tetanus vaccination is it advisable to start one or two month before travelling. You give your Immune system enough time to produce his own protection. For Hepatitis is one month enough to get up to three inoculations. For the yellow fever vaccination is ten days before departure enough time. Remember to bring your vaccination pass with you! Brazil will ask for the yellow fever vaccinating entering the country!

Ninety-five percent from all doctors will tell you that a malaria prophylaxis is by all means necessary. In my 10 years experience as tour guide, I have seen a lot of bad reactions from malaria prophylaxis. Many tourists are complaining about headache, bad stomach-ache, eye glimmer, two fainted and one almost died. All this happens after taking the „LARIAM" pills for malaria. I recommend a stand by pack. ashould you be infected from malaria you have your medicine with you and when not even better that you did not take these pills. I am since 1993 in Venezuela and went to the worst malaria zones like Delta de Orinoco, Amazon, Pantanal..... , and did also most of my colleagues and in total I knew from three malaria infected people and they are all cured very quickly.

Until now we haven't heard anything about SARS in Venezuela or Brazil. The Corona Virus which passed from animals to humans is mainly in South china and Hong Kong active. There might be some people suffering in a hospital in Caracas or Sao Paolo but there is no danger at all in the country. If you like to bring your first aid with you think about the following products: Anodyne, something for disinfections and for a bad stomach-ache, sunburn and for mosquito bites, condoms, clinical thermometer, plaster and
some dressing material. But ask any pharmacy for help or advice, better safe than sorry!

Every traveller should be aware that his normal health insurance are not enough protection for bigger trips if you think about having a little fun during your vacation. Like doing a Trek, being in the jungle or whatever. Think about how much would be the cost of a rescue by helicopter from a mountain or in the jungle or to bring you back home. And now think how much will cost a private health insurance! Check it out! You will find in the most guidebooks also a medicine part. I recommend the Footprint Guidebook for Venezuela.

Have fun!