Is bird flu going to transform itself into a massive killer of humans? Or is it simply going to fade away?

If you listen to many of our health experts, you would already be cordoning off your house. Last month, Tennessee virologist Robert Webster, known for his research efforts as “the flu hunter,” insisted on national television that “society just can’t accept the idea that 50 percent of the population could die.”

This hysterical prophecy from a serious scientist compounded previous statements made by Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, who said bird flu is “a time bomb waiting to go off,” and Julie Gerberding, director of the Centers for Disease Control and Prevention, who agrees with most experts that regarding a serious avian flu pandemic: “It’s not a question of if; it’s a question of when.” Even the cautious secretary of Health and Human Services, Mike Leavitt, recently let slip the alarmist notion that it was time to talk about closing schools and stockpiling tuna fish and powdered milk.

But the science on the H5N1 bird flu virus may not support these conclusions. Two important studies published just last month in top science journals show that this bird flu virus is still multiple mutations away from being able to pass easily among humans. This bird flu appears to be better absorbed by the deep pockets of bird lungs, whereas human flu is absorbed by the cells of our upper airways.

The kind of real science found in these studies takes place in the laboratory trenches, not in the news conference or the cable news sound bite. In fact, the researchers who have been studying bird flu the longest and know the most about it are veterinarians.

David Swayne, director of the Southeast Poultry Laboratory at the U.S. Department of Agriculture, has worked on avian influenza for years. He takes all highly pathogenic bird flus seriously, including H5N1, but he thinks they can most often be controlled. Swayne told me that H5N1 might still be eradicated in birds with the help of “better diagnostic tools and improved strategies to protect birds from infection.”

Elizabeth Krushinskie, president of the American Association of Avian Pathologists, told me that “there is no selective (genetic) pressure to drive (H5N1) toward humans. It could just as easily move away.”

In its current form, this flu is far more deadly to birds than to humans. In 1997 in Hong Kong, where the first human cases appeared, more than 10 percent of the thousands of human contacts screened developed antibodies to the virus but never got sick. This means that even in regions where bird flu is spreading, it is difficult for people to get sick from it. Sneezing and coughing don’t transmit it, and cooking poultry kills it.

Science is best served by careful study, not by speculation and hysterical predictions. It makes far more sense for international efforts to focus on controlling this disease in birds, rather than sounding a hasty alarm for humans.

When our public health officials try too hard to warn us against the worst case, too often they forget that they are really scientists and not prophets.