I searched the ThaiVisa forums and found that no one has been asked for the International Health Certificate proving that they have received a Yellow Fever vaccination upon arrival in Thailand.
I spoke with a neighbor (British) today who works in Nigeria on rotation and lives here when not working. He has had the vaccination, he may have lost the certificate, but has never been asked for it at Immigration.
I agree that the Visa on Arrival process may be more demanding, and if I had to go through that I would be sure to have any/all documentation.
If you're holding an Argentinian passport then this is a non-issue as you have an exemption of visa requirements for 90 days.
As a side note, we did have a huge outbreak of "yellow fever" back in late November, 2008, which resulted in the closing of Suvarnabhumi airport for ~ two weeks. Then we had "red fever" in April, 2010. Not sure what is next; "blue fever" or "purple fever"?
