Not sure if things have changed but when I was headed for Africa a few years ago, although Yellow Fever Vaccine was offered by many clinics I was told only to get it at a designated center which gives you the YF card and is officially recognized. I was overseas at the time and had to get it at a government facility.I was told then that getting it a any other clinic would not be acceptable and I would not be allowed to re-enter without the government printed YF card. BTW YF is good for 10 years, and if you are planning to spend a fair amount of time overseas there are plently of other vaccines recommended as well depending on where you will be spending time. I had YF. Cholera, Typhoid, Hepatitis, Tetanus....... as I was in Africa and South Asia.