Causes

Influenza is a contagious respiratory illness caused by influenza viruses. It is spread when an infected person touches or shakes hands with another, sneezes, and coughs without covering their mouth, or touches objects like door knobs that other people may touch. Most healthy adults may be able to infect others beginning 1 day before symptoms develop and up to 5 days after becoming sick. That means that you may be able to pass on the influenza to someone else before you know you are sick as well as while you are sick.

Symptoms

The symptoms of influenza differ from those you have with a cold. They are usually more serious and typically start suddenly.

• Fever (usually high)
• Headache
• Extreme tiredness
• Dry cough
• Muscle aches

Treatment

Influenza is a viral infection, it cannot be treated with antibiotics.

Influenza antiviral drugs can reduce the severity of influenza symptoms and shorten the time you are sick by 1 to 2 days. They also may make you less contagious to other people.

There are two influenza antiviral drugs that are recommended for use in the United States, oseltamivir (Tamiflu®) and zanamavir (Relenza®). Antiviral drugs should be started within two days after you get sick. Side effects are different for each drug and should be discussed with your clinician before you start the medication. It is important to remember that influenza antiviral drugs are not a substitute for getting the influenza vaccine.

Prevention

• Cover your nose and mouth with a tissue when you cough or sneeze—throw the tissue away after you use it.
• Wash your hands often with soap and water, especially after you cough or sneeze. If you are not near water, use an alcohol-based hand cleaner.
• Avoid close contact with people who are sick. When you are sick, keep your distance from others to protect them from getting sick too.
• Try not to touch your eyes, nose or mouth. Germs often spread this way.
• The best way to protect yourself and others against influenza is to get a yearly influenza vaccine.

The single best way to prevent influenza is to get an influenza vaccination each fall. There are two types of vaccines:

• The “influenza shot” – an inactivated vaccine (containing killed virus) that is given with a needle. The influenza shot is approved for use in people 6 months of age and older, including healthy people and people with chronic medical conditions.
• The nasal-spray influenza vaccine – a vaccine made with live, weakened influenza viruses that do not cause influenza approved for use in healthy people 2 years through 49 years of age who are not pregnant.

When to Get Vaccinated

October or November is the best time to get vaccinated, but you can still get vaccinated in December and later. Influenza season can begin as early as October and last as late as May. Antibodies that protect against infection develop about two weeks after you receive the vaccination.

Vaccine effectiveness is not 100%, and some people can still get influenza. For example, some older people and people with certain chronic illnesses might develop less immunity than healthy young adults after vaccination. However, even for these high-risk individuals, the vaccine still can provide protection against getting severe complications from influenza.

Who Should Get Vaccinated Every Year?

• People who want to reduce their risk of becoming ill with influenza or spreading it to others
• People who are at high risk for complications from influenza, including:
  • children who are 6 months to 5 years old
  • pregnant women
  • people who are 50 years or older
  • people of any age who have chronic medical conditions such as heart, lung (including asthma) or kidney disease, or metabolic disorders (for example, diabetes)
  • people of any age who have a weakened immune system
  • people who live in nursing homes or other long-term care facilities
     
• People who live with or care for others who are at high risk for influenza complications, including healthy household contacts of:
  • people at high risk for complications from influenza
  • children less than 6 months old (children under 6 months old cannot get vaccinated)

Talk to Your Clinician Before Getting the Influenza Vaccine if You:

• have ever had a severe allergic reaction to chicken eggs or to a previous dose of influenza vaccine
• developed Guillain-Barré syndrome within six weeks after getting the influenza vaccine
  

• Children less than 2 years old
• People who are 50 and older
• People with certain chronic medical conditions that put them at high risk for complications from influenza
• Children who have a history of wheezing and are less than five years old
• Children or adolescents receiving aspirin
• People with a history of Guillain-Barré syndrome
• Pregnant women

Self-Care

Try these steps to help you feel more comfortable:

• Stay home and get the rest you need. It is one of the best ways to deal with influenza, and it keeps you from spreading it to other people.
• Drink extra fluids. Warm fluids are soothing, especially if your throat is irritated. Drinking adequate fluids is important to prevent dehydration when you have a fever. If you are light-headed when you stand up, liquids that contain salt, such as sport drinks or soup, may be helpful.
• Take medication to relieve the symptoms of influenza. A decongestant (Sudafed®) can help with any congestion. Never give aspirin to children or teenagers to treat influenza symptoms without first speaking to your clinician.