Utah Influenza Surveillance

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Communicable Disease Control

Epidemiology

Utah Public Health Lab

 


Influenza

 

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What is influenza?

Influenza (flu) is a very contagious viral infection of the nose, throat, bronchial tubes, and lungs. There are two main types of influenza virus: A and B. Each type includes many different strains which tend to change each year.

What are the symptoms of influenza?

Typical symptoms of influenza include fever, chills, muscle aches, headache, stuffy or runny nose, cough sore throat and general weakness. These symptoms usually appear one to five days after a person is exposed to the virus.

How is influenza transmitted?

Influenza is spread through contact with droplets from the nose and throat of an infected person during coughing and sneezing.

When and how long is a person able to spread influenza?

The contagious period varies, but probably begins the day before symptoms appear and lasts for about a week.

Can influenza be dangerous?

Yes. Although most people recover from the disease within one week, some have life-threatening complications such as pneumonia and may need to be hospitalized. Approximately 20,000 people die each year in the United States from influenza or related complications.

Can influenza be prevented?

Yes. The best means of preventing influenza is by immunization. Because the types and strains of viruses that cause influenza change often, an influenza vaccination should be received every year. Some people who have been exposed to influenza may be prescribed an anti-viral medication to prevent or reduce the severity of illness.

Who should be vaccinated?

The following groups are at increased risk for serious illness and should receive vaccine:

  • all people 50 years of age and older;
  • adults and children with long-term heart or lung problems, including asthma;
  • residents of nursing homes and other facilities housing patients of any age who have serious long-term health problems;
  • people who have kidney disease, cystic fibrosis, diabetes, anemia, cancer or immunological disorders and other medical conditions for which they are under the close supervision of a doctor, including people with HIV inflection;
  • children aged 6 months to 18 years on long-term aspirin therapy and, therefore, might be at risk for developing Reye syndrome after influenza infection; and
  • women who will be in the second or third trimester of pregnancy during the influenza season.

Others who should receive the vaccine include household contacts of high risk people and health care workers who provide care to high-risk patients.

Who should NOT be vaccinated?

The following groups should not be vaccinated without first consulting a physician:

  • people who are allergic to eggs;
  • people who have had a severe allergic reaction to a previous dose of influenza vaccine;
  • people who previously developed Guillain-Barré Syndrome (GBS) after receiving influenza vaccine;
  • people with a moderate to severe acute illness should not be vaccinated until their symptoms have decreased.

How is influenza treated?

When taken within 2 days of illness onset, prescription anti-viral drugs can reduce the duration of uncomplicated influenza. There are four licensed anti-viral drugs available in the United States: amantadine and rimantadine for treatment and prevention of type A influenza, and oseltamivir and zanamivir for treatment of types A and B influenza. Oseltamivir is currently the only anti-viral drug approved for both treatment and prevention of types A and B influenza.

Where can I get more information?

  • your private health care providers;
  • your local public health departments; and
  • The Utah Department of Health, Office of Epidemiology (801) 538-6191

Utah Department of Health
Office of Epidemiology
October 2002