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Facts about the "Flu"

GET YOUR FLU SHOT BEFORE NOVEMBER

February 09, 2005 --  

 Facts about the Influenza Virus

•The influenza virus changes every year.
•These changes cause seasonal flu epidemics.
•These changes mean that the flu vaccine must be reformulated every year.

 

The influenza virus causes one of the world's most serious respiratory illnesses. It is potentially fatal and infects humans in the tens of millions each year. The virus changes each year - sometimes a little, sometimes a lot. Major changes, known as subtype changes, produce worldwide epidemics called pandemics. In 1918, the influenza A virus subtype, known as the "Spanish Flu," killed 500,000 people in the U.S. and 20 million people globally. In 1957, the "Asian Flu" killed 70,000 in the U.S., and in 1968, the "Hong Kong Flu" caused another epidemic. The minor changes are called strain changes, but they are not always so minor. In the 1997-1998 flu season, the "A/Sidney" strain caused almost double the U.S. yearly average of 20,000 influenza-related deaths. These yearly changes demand yearly vaccine alterations.

The next pandemic can occur at anytime. It will be a different virus subtype, one that may never have been encountered by humans. Because we will have no immunity, it will kill many more than the yearly average of 20,000 people in the U.S. Even young healthy adults will have a severe illness.

How Influenza Is Spread

•Influenza is spread via respiratory secretions (coughing and sneezing).
•The incubation period is from 1 to 4 days.
•Infected persons are contagious for about a week, although children and immunocompromised patients are contagious for a longer period of time.

 

Influenza virus in humans is spread via respiratory secretions from infected persons, through coughing and sneezing. These aerosols of viruses contaminate the air, hands, and surfaces of our environment. The incubation period is very short (from 1 to 4 days), and attack rates range from 15-40% in a normal year. In nursing homes, 60 out of 100 patients can be affected, with up to 30 fatalities. A person over age 65 is at risk because the immune system is weakened and, over the years, "forgets" it has been exposed to influenza.

Sick persons "shed" the virus and are contagious for about a week. Immunocompromised persons (e.g., those with cancer, AIDS, or who may be on immunosuppressants) easily contract influenza and shed virus for 2-3 weeks. School-age children are the first to become ill in each community and are the primary source of contagion since they shed virus for 7 to 10 days. Because they have little or no previous exposure to influenza, children have less immunity and can experience more severe forms of flu. Others at risk for serious influenza complications are patients with asthma, pulmonary disease, heart disease, diabetes, renal disease and anemia.

Overview

Vaccination Recommendations
• People aged 50 or older
• People with certain chronic diseases
• Nursing home residents
• Children and teenagers on long-term aspirin therapy
• People who come in frequent contact with high-risk patients - especially health care providers
• People with allergies to eggs should not receive the vaccine

 Vaccine Effectiveness

Vaccine effectiveness varies from one person to another. Studies of healthy young adults have shown influenza vaccine to be 70-90% effective in preventing illness.

Some people fear its side effects, but the influenza vaccine causes no side effects in most people. The rare exception is a severe allergic reaction in people with an allergy to eggs. Since viruses used in the vaccine are grown in hens' eggs, those who are seriously allergic to eggs should not receive the influenza vaccine.

Less than one third of those who receive the vaccine have some soreness in the area where it was administered. About 5% to 10% experience mild side effects, such as headache or low-grade fever for about a day after vaccination. These side effects are most likely to occur in children who have not been exposed to influenza virus in the past.

Contrary to popular belief, the U.S. influenza vaccine CANNOT CAUSE INFLUENZA because the vaccine is made from killed influenza viruses.

Each year, the vaccine is updated to include the most current influenza virus strains. This is why it is necessary to get the flu shot every year.

Influenza usually occurs in the United States each year from October until April. Activity is typically low until December, and usually peaks between January and March. Influenza vaccine should be administered from mid-October to mid-November. It takes one to two weeks from the time of vaccination to develop antibodies and provide protection.

Prevention of Influenza with Drugs

• The antivirals can be used to prevent influenza infection in children age one year and older.
• These antivirals may prove beneficial in high-risk or at-risk persons who have not been vaccinated or in immunocompromised patients.

What to expect:

• Fever over 102°
Fever generally lasts 3-5 days, and is often higher in the afternoons and evenings, with some decrease in the mornings. Fever typically runs higher in children and can be over 104°.
• Cough
The cough starts as dry and hacking and progresses by the 3rd day to wet with thick mucous. The cough can worsen for the next 4-7 days and could last for over 2 weeks. This is the major symptom of influenza. Cough in children can be croupy and serious. Smokers are at risk for significant bronchitis and pneumonia.
• Headaches and Muscle Aches
These can be severe for the first few days and will slowly improve.
• Fatigue
Fatigue is common and severe, lasting for 1-3 weeks.
• Sore Throat
Sore throat is most common in older children and adults. It can be severe for the first few days.
• Nasal Congestion and Red Eyes
Nasal congestion lasts for 1-2 weeks, and eyes may be red for 3-4 days.
• Vomiting or Diarrhea (in children <6 years of age)
Vomiting or diarrhea is unusual in adults. These symptoms are typically seen in children less than 6 years of age and last for the first few days.

Influenza is typically contagious for 5-7 days from fever onset.

 

General Treatment

• Non-aspirin fever reducers/pain relievers for fever, muscle aches and headaches
• Increased fluid intake
• Rest
• Antiviral therapy

Call your physician if:

• Your instincts tell you to be concerned. Trust them and call your doctor for advice.
• Your fever comes back after it has been gone 1-2 days or if you still have high fever after 4 or 5 days.
• Your cough becomes wheezy or rapid, you are having trouble breathing, or you are coughing up bloody or yellow-green mucous.
• You have any chronic illness (e.g., heart or lung trouble, asthma, cancer, a compromised immune system, diabetes, kidney, or blood cell problems), or if you smoke, and your condition worsens. These conditions put you at greater risk for complications.
• You have any of the following: severe confusion, seizures/convulsions, loss of consciousness, spasms, bleeding, heart irregularity, ear pain or prolonged headache.

For More Information Contact:

The Perkins Pediatric Clinic, LLC
111 North Royal Street; DeRidder, LA  70634
Tel: 337-462-6000
FAX: 337-462-6560
Internet: pedihelp@perkinspediatrics.com

Send mail to pedihelp@perkinspediatrics.com with questions or comments about this web site.
Copyright © 2002 The Perkins Pediatric Clinic, LLC
Last modified: 01/30/07