The International Certificate of Vaccination or Prophylaxis, or “Yellow Card”, is a folding yellow card containing a record of your vaccinations. It is the same size and shape as the passport and is generally stored with it. Each time that a medical professional provides a vaccination, it is noted and stamped.
Thankfully, we have a variety of different vaccinations available, covering some but not all of the world’s nasties. Travelers must do research and consult tropical medicine specialists to determine which vaccines are required or recommended for their geographic destinations. The CDC website at http://wwwnc.cdc.gov/travel/destinations/list [sic] is a good place to start.
The most important vaccination is Yellow Fever, which is required by almost every country. It has a special section in the Yellow Card. Yellow Fever was the 18th & 19th century equivalent of HIV or Ebola; it is a particularly nasty illness. You will not be allowed past immigration in most countries without a valid Yellow Fever immunization stamp in your Yellow Card.
There are many other vaccines that are recommended for different regions. Some may be required for limited times during active outbreaks. Consult a tropical medicine specialist for details.
Americans will often have received measles, mumps, and rubella (MMR); pertussis; polio; and tetanus and diphtheria (Td) as children and need only boosters. Other common vaccines are hepatitis A and B, Japanese encephalitis, meningococcal meningitis, and typhoid. Rabies vaccine is less common but occasionally prudent. A cholera vaccine is available in Europe but not America; it is only partially effective.
It is best to space out vaccinations over a couple of months before your first trip. Many vaccinations require several shots to be effective. Get a couple each week rather than all at the same time. Many healthcare facilities may have to special order some vaccines.
Malaria Prophylaxis is not recorded in the yellow card; see next week’s blog post for details.
HINT: Unlike a passport, the Yellow Card is usually printed on normal cardstock and will quickly start showing signs of wear and tear, particularly if crammed into a pocket. Losing it, or having it fall apart, is bad news, because it means you will need to get all the vaccines over again. Take good care of it. Some healthcare providers offer an inexpensive ($1-$2) plastic sleeve, which is strongly recommended.

IMPORTANT: If you do not believe in vaccinations, please do everyone a favor and simply stay home. Your health will be at serious risk traveling to the developing world, and you will be a danger to the friends you are going to visit and the family you return to in the US.