Science / Medicine : Vaccine Seen Surest Way to Avoid Misery of Flu Season : Influenza: Older Americans can escape the illness and its sometimes deadly complications with a simple preventive measure. And November is the best time to get the shot.

The old adage “an ounce of prevention is worth a pound of cure” holds true for the flu.

Each winter millions of Americans suffer the fever, aches and pains of influenza. Most recover from the effects in a week or so, but for many older people the flu and its complications are extremely serious.

While the body’s immune system is busy fighting the flu, a person is less able to resist pneumonia, another life-threatening infection. Older people and those with chronic diseases such as heart disease, emphysema, asthma and diabetes have the greatest risk of developing pneumonia along with the flu.

And older people are more likely to require hospitalization. Flu and pneumonia combined are the sixth leading cause of death in the United States, and 80% to 90% of the deaths are in people 65 and older.

But flu and its complications need not be deadly, and can be prevented by vaccinating high-risk individuals six to eight weeks before the season begins.

Influenza is caused by a virus that infects the nose, throat and lungs. Flu travels quickly, especially during winter in crowded indoor places like malls, grocery stores, theaters and hospitals. When someone with the flu coughs or sneezes, droplets containing particles of the virus spread to others.

After infection, symptoms usually appear in two to four days; the disease continues to be contagious for another three to four days.

Once the virus enters the body, it multiplies and causes a variety of well-known complaints, including chills and fever, headache, runny nose, sore throat and a dry cough. Extreme weakness and muscle aches and pains often last for several days. If the virus invades the lungs, viral pneumonia can develop.

To prevent the flu, people 65 and older and residents of nursing homes and other chronic-care facilities should be vaccinated. Also, health professionals, nursing home workers and family members who live with someone older than 65 should get a flu shot to avoid spreading the disease to those at risk.

Unlike other viruses, the flu virus changes from time to time. Because different strains of the virus tend to spread flu each season, a new vaccine is prepared every year. It contains strains of the flu virus recently circulating worldwide and believed likely to hit during the coming winter. Nicknames such as the “Spanish flu” and “Hong Kong flu” refer to places where large outbreaks of new flu strains have first appeared.

The vaccine is made from highly purified, killed viruses. Because the flu shot does not contain infectious viruses, it does not cause the flu. The most common side effect is a sore arm, which occurs in less than one-third of those vaccinated and usually lasts only a day or so. A few people also may develop a brief low-grade fever and some minor aches and pains, which begin six to 12 hours after vaccination and can persist for one or two days.

If a person has no special reason not to take aspirin, low doses (such as one tablet every three to four hours) usually will relieve these symptoms.

Immediate allergic reactions, such as hives, rarely occur after influenza vaccination. Anyone allergic to eggs, which are used to grow the virus for the vaccine, should not receive the vaccine, as some egg protein may be present.

Because the flu vaccine takes several weeks to work, the best time to be vaccinated is in November. A vaccine also is available against the most common types of bacteria that cause pneumonia. The flu shot can be given at the same time as the pneumonia vaccine without increasing the side effects. The flu shot must be given every year, but the pneumonia vaccine should be given only once.

In addition to the flu shot, an antiviral drug--amantadine--can prevent infection by certain strains. The drug is useful for people who have not had the vaccine or as extra protection for those who have been immunized.

When taken soon after the early signs are felt, amantadine reduces the duration of fever and other symptoms. It also can prevent infection if taken during the entire four- to six-week course of a flu epidemic.

After people stop taking the drug, they become susceptible to the virus again. It occasionally causes difficulty sleeping, impaired concentration and dizziness, and has been associated with falls in older people. As with all medication, patients should take it only with a doctor’s recommendation.

INFLUENZA / PNEUMONIA DEATH TOLLS

Age breakdown for 1987 deaths

Under 14 Over 65 Deaths from flu and pneumonia 987 60,542 Deaths from flu 15 533