What inoculations do I need to visit Costa Rica and how is medical care in Costa Rica?

There are no required inoculations for Costa Rica, but it is a good idea to check with your physician for recommendations of optional inoculations and health precautions. Costa Rica is suffering an outbreak of dengue fever (both classic and hemorrhagic), although the incidence remains lower than in other Central American countries. Dengue is transmitted by mosquito bite and there is no vaccine. Anyone planning to travel in affected areas should take steps to avoid mosquito bites. These include wearing long sleeves and pants, using insect repellent containing DEET on exposed skin, and sleeping under mosquito netting.
Medical care in the capital city of San Jose is adequate. However, in areas outside of San Jose, medical care is more limited. Doctors and hospitals often expect immediate cash payment for health services. U.S. medical insurance is not always valid outside the United States. Supplemental medical insurance with specific overseas coverage, including provision for medical evacuation, has proven useful in many emergencies.
For additional health information, travelers may contact the Centers for Disease Control and Prevention's international travelers hotline at (404) 332-4559.

Yellow Fever Vaccination Requirement to Enter Costa Rica 

The Costa Rican government instituted a requirement that starting on November 1st, 2007, persons traveling to Costa Rica from certain countries in South America and Sub-Sahara Africa must have an International Certificate of Vaccination against Yellow Fever.  Those affected countries are:  Angola, Benin, Burkina Faso, Cameroon, Democratic Republic of Congo, Gabon, Gambia, Ghana, Guinea, Liberia, Nigeria, Sierra Leone, Sudan, Bolivia, Brazil, Colombia, Ecuador, Peru, French Guiana and Venezuela.