One concern that I always hear from people everytime they intend to go to Costa Rica is the idea of having malaria. Most websites tend to say that one needs to have malaria vaccine shots once here. They lump Costa Rica together with other tropical countries. What these sites do not consider is that Costa Rica is unlike other Central American countries where public health standards are very low.
Furthermore, reported cases of malaria here in this country have not been heard of for quite a long time already, except for a few cases regularly reported in Limon province and other remote locations in the Talamanca Mountains and along the border with Nicaragua. It is advised that you bring chloroquine with you just in case ou intend to go to places near the areas with reported cases of malaria. Otherwise, if you are just going to on a rainforest expedition somewhere else, you should not bother about this dsisease because usually, the rainforests are too high for the mosquitoes' reach.
In any case, if you really feel that you have to have malarial vaccine, then of course, you are free to do so. Just remember that this is not a requirement once you decide to enter Costa Rican territory. This isn't much help, but this article from eHow.com says that the most recent studies on malarial vaccine show that there are hardly any side effects once you take in the vaccine, except that your blood will have higher levels of malaria antibodies. The malaria vaccine featured in that article will still be subject to further tests until it is hopefully released to the public by early 2010.
More than any online guide, however, it is always advisable to check with your country's foreign ministry and/or doctor to find out what kind of vaccine shots you need. It would also help to check with the Costa Rican embassy in your country to find out if there were any recent reported cases of malaria or simmilar diseases.
