Germs of Truth

‘Tis the season--still--for that germy double whammy: the common cold and the more exotic influenza. A cold attacks the airways: Its hallmarks are a stuffed-up, runny nose, hacking cough and scratchy throat. Influenza mugs the whole body with fever, chills, fatigue, aches and an overall crummy feeling.

Ubiquitous, contagious and incurable, the two have much in common. Both usually last a week or more. Both are caused by viruses, a word whose Latin root means “slimy poison.”

But while some of their symptoms overlap and their names are invoked by some sufferers almost interchangeably, the common cold and influenza, or flu, are distinct illnesses caused by separate viral “bugs.” More than 200 viruses, about half known as rhinoviruses--from the Greek word for “nose”--can cause a cold. An array of shifting viral strains--classified as A, B or C types and named for the city where they were first identified--is responsible for the influenza epidemics that annually sweep the globe.

Each year, they make millions of people miserable. Perhaps because they are so widespread and incurable, flu and colds have also given rise to a rich if sometimes-misleading mythology, including . . .

Wear a Coat or You’ll Catch Cold

Wrong.

Harsh weather alone will not cause flu or the common cold. For either illness to strike, it takes a germ, a virus.

“It has nothing to do with being outside in cold weather,” according to guidelines for prevention and treatment of colds and flu compiled recently by the American Lung Assn.

A cold takes hold when the virus reaches the lining of nasal passages, via the eyes, nose or mouth. Colds are spread mainly by touch, kissing or other direct contact--as when someone with a cold coughs or sneezes in your face. People are most contagious during the first three days of a cold.

The influenza virus is spread mainly by microscopic droplets released into the air by sneezing, coughing, speaking or breathing. When the droplets are inhaled by another person, the virus can invade the nose, throat or airways in its new host.

Colds and flu flourish in winter because people spend more time cooped up inside--increasing the chances of person-to-person spread--and because the most common viruses survive better in low humidity.

Exposure to extreme cold can increase susceptibility to pneumonia--inflammation of the lungs. And recent studies have concluded that chronic, long-lasting emotional stress can make people more vulnerable to colds.

You Can Get the Flu From a Flu Shot

Not so.

The viruses that are used to make the flu vaccine are grown in chicken eggs, then killed by a chemical so that they are no longer infectious. The most common side effect is a mildly sore arm. In some people, especially children who have not been exposed to the flu, the vaccine can cause flu-like symptoms of fever and tiredness for a day or two.

An annual flu shot is recommended for: people 65 or older; those with chronic heart, lung or kidney disease, diabetes, anemia or asthma; residents of nursing homes; and health-care workers. In addition, doctors increasingly advise a flu shot for anyone who wants to reduce the risk of getting sick. (People allergic to eggs, however, should not get a flu shot, because the vaccine may contain some egg protein.)

“The flu vaccine significantly reduces the chance of infection, and even if you do get sick, your symptoms will be much less severe,” said Jehan El-Bayoumi, an internist at George Washington University Medical Center. She advises even healthy people to consider a flu shot--to protect themselves and those around them.

For the common cold, medical science has little to offer in the way of protection. There is no vaccine against cold viruses. The best way to prevent colds is to wash your hands a lot and not get sneezed on.

Starve a Cold, Feed a Fever

No one knows where that saying came from, or why it caught on. But it’s misleading at best, doctors say.

There’s no reason not to eat when you have a cold, or to force yourself to eat when you’re woozy from a flu-caused fever. And if you’ve heard it as “Feed a cold, starve a fever,” it doesn’t make any sense that way, either.

The point is: Drink plenty of nonalcoholic fluids, whether you have a cold or a fever. And eat when you feel like it. (“Stomach flu” is a misnomer, because the influenza virus almost never causes gastrointestinal problems; what people mean by “stomach flu” is something else.)

Treat a Cold and It Lasts a Week; Ignore It and It Lasts Seven Days

That adage remains largely true.

But medications can lessen discomfort and help get cold sufferers through the night or day. Nonprescription remedies, including decongestants, cough suppressants and antihistamines, may relieve symptoms but cannot cure, prevent or shorten a cold. Acetaminophen (Tylenol) is recommended for headache and general discomfort, because it is less likely than aspirin or other nonsteroidal anti-inflammatory drugs to upset the stomach.

Aspirin should not be given to children younger than 18, because it has been linked to increased risk of Reye’s syndrome, a rare but serious liver and brain disease in children. Antibiotics, which fight off bacterial infections, won’t do any good against either flu or colds, which are caused by viruses. Only complications such as ear infections or pneumonia call for antibiotics.

“Usually it’s better not to rush to treatment,” said Anne L. Davis, a lung specialist at New York University School of Medicine and past president of the American Thoracic Society and the American Lung Assn.

“We, as doctors and the public, have to resist the temptation of expecting that an antibiotic will make the cold go away any faster,” George Washington’s El-Bayoumi said. Only in 2% of cases, she said, is there reason to suspect a secondary bacterial infection that would warrant use of antibiotics.

“It’s somewhat of a judgment call,” El-Bayoumi said, noting that she is more likely to prescribe antibiotics in patients whose immune systems are already weakened--because a possible bacterial infection in such patients would pose a serious danger.

A pair of antiviral drugs, amantadine (Symmetrel) and rimantadine (Flumadine), can help ward off A-type flu or lessen its severity--if they are given promptly, within the first day or two after symptoms appear.

Chicken Soup’s the Way to Go

Grandma was at least partly right.

Chicken soup has no special curative effect on colds or flu, but its time-honored role as a home remedy for misery has won over the doctors on at least two counts:

First, soup is a good source of liquids. Second, anything that tastes good and makes you feel better when you’re sick deserves a place in the medical armamentarium.

Intake of fluids--water, juice, weak or herbal tea--is important, doctors say. Heated indoor air, which tends to be drier than outdoor air, parches skin and airways and causes dehydration. Hot liquids also can help relieve a scratchy throat.

But while fluids are a good idea, doctors warn against alcohol and coffee. Both have a diuretic effect, which defeats the purpose by wringing moisture out of the body.

When You Have a Cold, Working Will Make It Worse

Probably not. Going to work or school with a cold is unlikely to prolong the illness, according to the Lung Assn. and other experts. Many people find they can function close to normally despite a cold. Flu is more likely to make a person feel like staying home--and more prone to a boomerang effect if patients don’t rest and give themselves time to recover.

But going to work or school while sick increases the chance of infecting others. So doctors caution: Don’t be a hero. It may make others sick.