I think Hep A is a good one, no matter where you travel. Anything else is up to you. In 20 years of traveling in Latin America, I have never done any malaria treatment. And I’ve never had malaria — which, by the way, has been eradicated in Ecuador. I do know that if you travel directly from Ecuador or Colombia to Costa Rica you will need proof of the Yellow Fever vaccine, Costa Rica is the only country I know of that requires this, for passengers traveling from a country known to have YF in their jungle regions. By the way, I don’t know that I know anyone who has ever had Yellow Fever.