At one time there were a list of requirements for each country for travelers. In recent years most vaccination requirements have been dropped, though Yellow Fever is still required in some tropical regions. Before traveling to a certain country it is advised to check with the Centers for Disease Prevention and Control (CDC) for information on vaccines you should consider. www.cdc.gov
Vaccines are not required by countries for the protection of travelers, contrary to popular belief. The requirements were to protect the citizens of that country from any disease that could be spread by travelers.
There is always a possibility that you or a member of your party will have a health emergency. This could be illness or injury. In most emergency situations the best course of action is to go to the closest hospital. Severe situations will have the responding authorities choosing the closest place for treatment. If you or the ill/injured person is stable, ask locals where to find the best available care. As in your hometown, everyone will have an opinion on where to be treated.
It is possible to find clinics that are familiar with treating travelers and the unique needs of foreign citizens. The International Society of Travel Medicine offers training and certification to clinicians around the world. You can visit their website to find out if there are certified clinics in the area you plan to travel.
The ISTM website also has information on outbreaks around the globe. The society was founded in 1991 and strives to make travel healthier for all who wish to globetrot. All areas of medical study are included in the mission statement and the society fosters communication between physicians in as many countries as possible.
For more information on outbreaks around the world and how travelers can protect themselves while visiting other countries and again at home after traveling, the CDC offers a wealth of information on nearly every disease. From medicine to injury, the CDC is not just an American department, like the ISTM it reaches around the world for health.