Wednesday, November 12, 2008

Don’t let flu season catch you off guard

Don’t let flu season catch you off guard
By Harvard Health Letter

It happens every year. The days grow shorter, the temperature drops, footballs fly — and the flu strikes. Influenza is so common that it’s easy to dismiss this seasonal affliction as “just a virus” or “just the flu.”

It’s true that the flu is caused by a virus and that most patients recover without specific therapy. But it’s also true that thousands of Americans die from the flu each year, and millions are sick enough to miss work or school. Influenza is a serious infection — but it can be prevented and treated.

Meet the flu bug

A large group of viruses belongs to the influenza family. Nearly all human infections are caused by human strains of the influenza A or B virus.

Because different strains of the virus crop up every year, new outbreaks occur annually.

In the United States, the flu season runs roughly from Thanksgiving to Easter, with most cases occurring in the dead of winter. In a typical year, up to 10 percent of us get the flu, more than 200,000 people are sick enough to require hospitalization, and about 36,000 Americans die from the infection.


After an incubation period of just one to two days, the symptoms start abruptly. Most patients are feverish, and high temperatures in the range of 103 degrees to 104 degrees are common. Nearly everyone has a runny nose and sore throat, but unlike ordinary colds, the flu also produces a hacking, dry cough. Muscle and joint aches can be severe. Headache, burning eyes, weakness, and extreme fatigue add to the misery.


The most serious — and deadly — complication is pneumonia. Young children, senior citizens and people with chronic illnesses are at greatest risk. Other flu complications can include asthma attacks, ear infections, bronchitis, sinusitis, inflammation of the heart or other muscles, and inflammation of the nervous system.

Prevention: Hygiene

A few simple precautions can help protect you and your family:

• Wash your hands. Alcohol-based hand rubs and gels are best. Ordinary soap and water will also help, and it’s not necessary to use very hot water or “antibacterial” soaps. Wash carefully after any contact with folks who have flulike symptoms.

• Keep your distance. The flu is most contagious within 3 feet of a patient.

• Wear a mask if you’re in a high-risk group and you can’t avoid getting near possible flu victims. Be sure your mask fits well. Keep it free of saliva and dry, and change it periodically. N95 respirator masks are best.

• Protect others. Don’t go to work or school if you have the flu. Use a tissue to cover your mouth when you sneeze or cough, and dispose of it properly.

Prevention: Vaccination

New vaccines are produced for every flu season; each protects against the two strains of influenza A and one strain of influenza B that are most likely heading our way in the fall. In the United States, October and November are the ideal months to get the vaccine. Children ages 6 months to 8 years who have never been immunized need two doses, but one dose will suffice for all others.

Two types of flu vaccine are available. The nasal spray can be used only by healthy, non-pregnant individuals ages 2 to 49. The injectable vaccine can be given to nearly everyone, except people who are allergic to eggs or to the vaccine itself. Side effects are mild and uncommon, amounting to a slightly sore arm or a slight fever.

Immunization can reduce your risk of catching the flu by up to 80 percent. That’s a big benefit, but nearly half the people who need protection the most don’t get it. If vaccine supplies are adequate, everyone older than 6 months should get a flu vaccine this fall. Here is a list of high-priority vaccine candidates:

• All children ages 6 months to 4 years.

• All adults age 50 and older.

• Children and adolescents ages 6 months to 18 years who receive long-term aspirin therapy.

• Women who are likely to be pregnant during the flu season.

• People who have asthma, diabetes or chronic diseases of their lungs, heart, blood, kidneys or liver.

• People who have illnesses or take medications that impair the immune system.

• Residents of chronic-care facilities.

• Health care personnel and child care providers.

• Caregivers and household contacts of people with medical conditions that put them at risk.


Antibiotics don’t work against viruses, including influenza. But while there are no medications for ordinary viruses, special prescription drugs can be used to treat or prevent the flu.

Both medications target a viral enzyme called neuraminidase. Neither will cure the flu, but they can ease and shorten the illness if started within the first 24 to 36 hours of flu symptoms. Both drugs can also be used to prevent influenza in unvaccinated people who are exposed to the infection.

Zanamivir (Relenza) is administered by inhalation from a nebulizer. It is approved for prevention in people age 5 and older and for treatment in people age 7 and older. Side effects may include wheezing, nausea and vomiting; behavioral abnormalities have also been reported.

Oseltamivir (Tamiflu) is available in tablet form. It is approved for prevention and treatment in patients above 1 year of age. Side effects may include nausea and vomiting; behavioral abnormalities have also been reported.

If you get the flu and can start treatment within about 36 hours, ask your doctor about oseltamivir or zanamivir.

With or without an antiviral drug, be sure to get lots of rest and drink plenty of fluids. Acetaminophen (Tylenol and other brands) can help ease fever and aches; aspirin is also effective, but should never be used by flu patients under 18.

And be sure to contact your doctor promptly if you think you’re developing pneumonia or other complications that may require antibiotics or hospitalization.

Flu Shot

Unexpected benefits

Protection from the flu is reason enough to get a flu shot every fall. But there’s even more. A major study of 286,383 people age 65 and above found that flu vaccinations were associated with a 19 percent to 23 percent reduction in the risk of hospitalizations for heart disease and stroke, along with a 29 percent to 32 percent reduction in the risk of hospitalization for influenza or pneumonia. All in all, senior citizens who got flu shots had a nearly 50 percent reduction in the risk of death during the winter flu season.

Why Winter ?

The flu loves winter. In the Northern Hemisphere, it comes around between November and March, but in the Southern Hemisphere, it hits from May to September, the coldest months. In the tropics, however, there is no true flu season — and very little flu.

Many respiratory infections peak in winter, when people cluster together indoors. But for years, scientists have wondered if there is something special about the influenza virus that accounts for its striking seasonality. A 2007 study found an answer.

Using guinea pigs infected with human flu viruses, scientists in New York found that the virus is transmitted much more efficiently in a cool environment. Animals who were housed at 41 degrees shed the virus nearly two days longer than animals housed at 68 degrees, and a temperature of 86 degrees blocked transmission of the virus altogether. Low humidity provided another boost for the bug; The virus spread much more readily at 20 percent humidity than at 80 percent.

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