When is an International Certificate of Vaccination necessary?

I was reading an old answer that referenced the International Certificate of Vaccination or Prophylaxis they carried in their passport. I've never heard of this before, despite getting several travel vaccinations and doing a fair bit of international travel.

My question is: when is a document like this necessary? And should I have received one from the travel clinic I went to in the US for my vaccinations?

Best Answer

Depends on where you're travelling to of course, but according to the WHO website the only disease that this certificate is required for is Yellow Fever.

The only disease specifically designated in the International Health Regulations (2005) for which proof of vaccination or prophylaxis may be required as a condition of entry to a State Party, is yellow fever. When administering this vaccine, the clinician must write “Yellow Fever” in the space provided on this certificate. This same certificate will also be used in the event that these Regulations are amended or a recommendation is made under these Regulations by the World Health Organization to designate another disease.

So if you have received a vaccination against this disease you should have this certificate. I don't know if this will be required to enter the countries where this disease exists but it may be required to re-enter the United States.