You've just told a friend about your upcoming trip to a once-in-a-lifetime locale like Machu Picchu or an African game park and he turns your wanderlust to whaa-waa with a simple question: "Have you gotten your shots?"

The question is not as bratty as it sounds. There are a handful of places on earth you literally can't visit without getting vaccinated, and a wide array of countries where a few recommended shots could be the difference between a dream vacay and a medevac.

Get the essential shots

"No matter where you're traveling, you should make sure you're up-to-date on routine vaccinations like T-dap (diptheria/tetanus/whopping cough), measles/mumps/rubella, and annual flu shots," recommends David Freeman, M.D., professor of medicine and epidemiology at the University of Alabama at Birmingham and treasurer/secretary of the International Society of Travel Medicine. Yawn? Think again: Measles is on the rise in Europe, where an anti-vaccine movement has discouraged many parents from having their kids inoculated against this potentially deadly disease. And nothing says "There's no place like home" like a bout of flu on the road.

Find out if your destination poses health risks

Visit a user-friendly web resource, such as the Centers for Disease Control (cdc.gov), to find a country-by-country index that explains what vaccinations are recommended. Headed for a South Africa game park? You should consider, with a doctor's advice, shots for typhoid, rabies, and hepatitis A. But if your game park is in Kenya, you may be advised to add a yellow fever vaccine to the list. In fact, many less-developed countries in sub-Saharan Africa and the Amazon River basin actually require visitors to show proof of yellow fever inoculation before they enter the country. And, though there's no vaccine against malaria, it is rampant in lower Africa and you should ask your doctor for an antimalarial prescription before you leave the U.S.

Weigh the costs of vaccinations

Freeman recommends that before traveling to a developing region, you visit a travel clinic—where the doctors' major focus is on helping you stay healthy on the road—at least four weeks before your trip. But there's a catch: Although routine shots are covered by most health insurance plans, a trip to a travel clinic and vaccines that are recommended or required for travel are usually not. That means that, on top of airfare and lodging, you may have to add $50-$100 for your exam/consult, $250-$300 for typhoid and hepatitis A shots, $150-$200 for yellow fever, and up to $1,000 for a rabies series. We're not suggesting you miss the chance to see the Big Five or explore the rain forest—just arm yourself with information and, if you must, roll up your sleeve!

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