Immunization can protect you against becoming infected with a disease. Many infectious diseases found in other countries can be prevented with immunization. You can greatly reduce your risk of contracting these diseases by being immunized against them before you travel.

With the increase in overseas travel, along with more remote destinations being visited, more travelers are requiring immunization than ever before:

• Travel to tropical and sub-tropical destinations is becoming more common, and potentially dangerous diseases are more likely to be present in these areas.
  
• Longer holidays abroad are becoming more common, which means longer exposure to the diseases found in the country visited.
  
• Holidays involving overseas travel to rural areas, where standards of hygiene and sanitation may be lower, are becoming more common. Medical treatment may also be more difficult to find in rural areas.

In addition, some countries require anyone wishing to enter to have an International Certificate of Vaccination. In particular, many tropical countries in Africa and South America will not accept travelers from an area in which yellow fever is known to be present unless they can prove they have been immunized against the disease.