There's a good chance that more Americans than usual will escape the fever and chills of the flu this year, predicts the Centers for Disease Control in Atlanta.
"We conduct a world-wide flu survelliance," says the CDC's Nancy Kater. "By knowing what viruses are circulating in other parts of the world, and how sick people get, and who gets sick, we have some clues" about how bad the flu season may be here.
The main strains now in circulation -- A-Philippines, A-Chile and B-USSR -- all passed through the United States last year, which was one of the mildest flu seasons recently. Many people already have been exposed to them and are immune.
But flu viruses constantly mutate into new forms, Kater cautions. In the unlikely event of a new strain arising, a severe epidemic could occur.
Although the flu season is expected to be mild, that doesn't mean that the 20 million to 40 million Americans who might develop some serious complication if they get the flu can skip their yearly vaccine, Kater said. Flu is a serious disease that kills 10,000 people every year on average.
People with severe diseases of the heart and lungs are especially in danger. "The total number of cardiovascular deaths in years of high flu activity increases," Kater notes. No one knows why.
Other mysteries surrounding influenza: how strains of flu virus mutate and why flu tends to strike in the winter and not all year round -- as it does in the tropics.
One theory about the "winter factor": "People come together indoors and make it easier to spread," says Robert Couch, director of the influenza research center at Baylor College of Medicine, Houston, Tex. "The virus does better in cool, dry conditions found in homes in the winter."
The classroom may be responsible for spreading flu around the community, Couch says. Evidence shows that "the best way to stop the flow of flu through the community is at the level of school-aged children. Researchers are trying to discover what can be done safely in the classroom, including vaccines for children."
Classrooms are great places to spread flu because it is "primarily transmitted by direct droplet contamination -- coughs and sneezes," said CDC's Kater.
The best prevention: Cover your mouth when you sneeze. "It takes very little to spread flu," Kater says. "If a person is shedding virus, he can contaminate a whole room by talking and breathing." Shot Spots
Even if this season does appear just mildly "fluish," people -- particularly those at high risk -- should get a vaccine, recommends the CDC. This year, two new groups are advised to get a flu shot: people with heart and lung diseases, and health care workers who take care of those at risk.
Others at risk: people over 65, anyone with a chronic illness -- such as heart, lung and kidney disease, diabetes and severe anemia -- and those whose immune system has been weakened by disease or treatments like cancer chemotherapy.
Several Washington area public health agencies provide free flu shots to the elderly and others at risk, including:
*The District: All 13 neighborhood health clinics. For locations call 673-6749.
*Arlington County: Geriatric Clinic, Fenwick Center, 800 S. Walter Reed Drive, vaccines for elderly who meet certain criteria. 553-8530.
*Fairfax County: Several locations, through the county Health Department. 691-2411.
*Montgomery County: October sites: Hebrew Academy (senior lunch program), 2010 Linden Lane, Silver Spring, 12:30-1:30 p.m., Oct. 24. Homecrest House Apartments, 14508 Homecrest Rd., Silver Spring, 10-11 a.m., Oct. 25. Bauer Park Apartments, 14635 Bauer Dr., Rockville, 10-11 a.m., Oct 26. Piney Branch Elementary School, (senior lunch program), 7710 Maple Ave., Takoma Park, 2-3 p.m., Oct. 29. Northeast Health Center, 14015 New Hampshire Ave., Silver Spring, 1:30-3:30 p.m., Oct 29. Dennis Avenue Health Center, 2000 Dennis Ave., Silver Spring, 1:30-2:30 p.m., Oct. 30. Rockville Health Center, 50 Monroe St., Rockville. 9 a.m.-noon, Oct. 31. More information: 279-1240.
*Prince Georges County: Beltsville Senior Center, Beltsville Community Center, 3900 Sellman Road, Beltsville, 10 a.m.-noon Oct. 25. Dyer Health Center, 9314 Piscataway Road, Clinton, 10 a.m.-noon, Oct. 31. 386-0110. Silver Spring, 1:30-2:30 p.m., Oct. 30. Rockville Health Center, 50 Monroe St., Rockville. 9 a.m.-noon, Oct. 31. More information: 279-1240.
Prince Georges County: Beltsville Senior Center, Beltsville Community Center, 3900 Sellman Road, Beltsville, 10 a.m.-noon Oct. 25. Dyer Health Center, 9314 Piscataway Road, Clinton, 10 a.m.-noon, Oct. 31. 386-0110.