Yes, it's that time of the year again-flu shot season. If you're a healthy adult under age 65, you may decide to skip this annual rite of fall. Even if you do come down with influenza--35 million to 50 million Americans are infected every year--chances are you'll just miss several days of work before recovering. But if you'd rather not contribute to the estimated $4.6 billion spent annually in the U.S. on flu-related medical costs, or take a chance on being one of the 20,000 or so Americans who die of the disease each year, keep this in mind: Flu shots work. Each spring, the Food & Drug Administration decides which viruses the next flu vaccine will target. Last year the agency got it slightly wrong, missing a newly discovered strain. Even so, the vaccine was over 80% effective against the untargeted virus.

NO NEEDLES? Flu vaccines are administered in October and early November, in anticipation of a flu season that usually stretches from December through April. The Centers for Disease Control & Prevention recommends vaccination most strongly for persons over age 65, adults and children with chronic disorders of the lungs or heart, children on aspirin therapy, women who will be in the last six months of their pregnancy during flu season, nursing-home residents, health-care workers, and people with diseases or treatments that weaken the immune system. There is a growing belief that all children from six months to 18 years should be vaccinated as well.

But what if you simply hate shots? An alternative is on the horizon. After 12 years of development, a flu vaccine injected by nasal spray is undergoing clinical trials and will likely be available for the 1999-2000 flu season. Developed by Aviron in Mountain View, Calif., in partnership with the National Institutes of Health, FluMist is a syringe-like device that delivers an aerosol spray. The spray is made from a weak form of the flu virus adapted to grow only in the cooler temperatures found in the nasal passages. There, the vaccine activates an immune response, producing antibodies that eliminate flu viruses in the nose before they can take hold in the airways. In a clinical trial involving 1,600 children, FluMist was 93% effective, a success rate comparable to injections. And in an unexpected development, it provided 98% protection against flu-related ear infections, a common side effect of the disease.

What if you get the flu? Its first signs are a headache, chills, and a dry cough, rapidly followed by fever and body aches. Doctors still recommend bed rest, plenty of fluids, and aspirin, acetaminophen, or ibuprofen to relieve these symptoms. Because the flu is a viral infection, antibiotics are useless, but two prescription drugs, amantadine and rimantadine, can be used to treat certain types of flu infections. They can reduce symptoms if taken within 48 hours of onset.

Unfortunately, the flu has no cure and must run its course. It can also be deadly, as health officials learned all too well in Hong Kong last year when 18 people came down with a deadly strain never before seen in humans. Six died. Virologists traced the virus back to birds--and ordered more than 1 million chickens and ducks slaughtered in a month.

MUTATING. "We acted on the slimmest of evidence, but it turns out we acted at just the right time," says Robert Webster, director of a World Health Organization laboratory that tracks flu viruses around the world. Otherwise, he says, a pandemic could have swept the globe, possibly killing as many as 20% of the population in some countries.

Virologists are increasingly worried that flu viruses are mutating into ever more deadly strains, much like the one that caused the Spanish Flu pandemic of 1918 that killed 20 million.

A prime example is a rapidly spreading new strain dubbed A/Sydney (flu viruses are named after the city where they were first isolated). A/Sydney was identified in Australia in June, 1997, and by October, it had reached Europe, the U.S., and Canada--causing influenza to reach epidemic proportions in the U.S. last January. The new strain was responsible for the majority of the higher-than-average flu-related deaths in nursing homes last winter. So you might want to get that flu shot after all.

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