This has always been a fundamental question for anyone traveling to places with questionable hygiene and threatening diseases-- such as parts of Asia, Africa, and Latin America. But these days, wise travelers should also ask themselves: Did you consult a travel-medicine specialist?And, How much did you pay?

"Destination-specific health risks are becoming more and more complex," says Dr. Bradley Connor, director of New York's Travel Health Services clinic. "A general physician isn't likely to have the specialized knowledge to address travelers' concerns. We're always hearing about travelers who were given incomplete or erroneous information by a general practitioner only to return with some highly preventable disease."

Researchers at the University of Massachusetts and the Centers for Disease Control (CDC) asked 635 people in international departure terminals of U.S. airports about their health precautions. Only 21 percent had visited a doctor at all-- and of those, the ones who had consulted travel-medicine specialists were more than twice as likely to have been properly advised and vaccinated. "What's of greater concern," says Dr. Craig Shapiro of the CDC, "is the 79 percent of travelers who didn't even bother to address the issue of travel health."

A good travel clinic won't just give you shots; it will also help you decide which immunizations you need depending on when and where you go-- the guidelines can change frequently. You may not be at risk for a certain disease in a given country, but the next one on your itinerary might refuse admission without a certificate of vaccination.

It's worth doing a little comparison shopping before rolling up your sleeve. Even at travel health clinics, pricing for the same shots can vary wildly (and most aren't covered by insurance, because they're considered elective medicine). For the hepatitis A vaccine, which consists of a primary shot and a follow-up booster, you would pay upwards of $250 in some physicians' offices ($85 per shot plus $50 per office visit), but as little as $130 at some clinics (a flat $65 per shot). Travelers who don't need to ask a lot of questions-- businesspeople who routinely visit the same destination, for example-- can save money by finding a clinic that is primarily an immunization center (they traditionally serve missionaries and the military). More bare-bones and shorter on advice than full-service travel health clinics, such centers charge per vaccination, have no general visit fees, and usually offer walk-in service.

Travel health clinics can also save you money by informing you where vaccines are cheaper overseas (costing as much as 75 percent less). In many countries, you can travel safely as long as you avoid certain high-risk areas. A good travel- medicine specialist can tell you where and when to get the appropriate medications or shots in your destination country in case you decide to visit one of those areas. That way, you avoid the expense until you're sure it's necessary.

Whatever you do, get in the know. As you find yourself sitting among 635 other travelers in a departure lounge, wouldn't you prefer to be one of the few who have been properly advised?Numbers to Know

For information on which vaccinations you should get, try the Centers for Disease Control website which lists disease reports by region; you can also hear reports over its phone line (888/232-3228) or have them faxed to you automatically. To find one of the 300 travel medicine clinics in the United States, check out the website of the International Society of Travel Medicine or Dr. Stuart R. Rose's annual International Travel Health Guide (Travel Medicine; 800/872-8633). Or call your local hospital-- many major ones have travelers' health departments, or can recommend a clinic.