Questions & Answers
Influenza - Seasonal - The Disease
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General Information

  1. What is seasonal influenza disease?

    Influenza, or the flu, is a contagious respiratory illness caused by influenza types A or B viruses. Influenza viruses are easily spread by airborne respiratory droplets from person to person (often by sneezing or coughing).

    Symptoms of infection include fever, muscle aches, headache, malaise (a general feeling of sickness), cough, sore throat, and runny nose. The flu causes mild illness in most people, the majority of whom will not need medical care or antiviral drugs, and usually recover in less than two weeks. Some people, however, can suffer flu complications that result in being hospitalized. Sometimes influenza infection results in death.

    Pneumonia, bronchitis, sinus infections and ear infections are examples of more severe flu-related complications. The flu also can make chronic health problems worse. For example, people with asthma may experience more frequent asthma attacks while they have the flu. The flu may also worsen congestive heart failure in people with this condition.

  2. How soon will I get sick after exposure to the influenza virus?
    Symptoms usually start 1 to 4 days, with an average of 2 days, after the virus enters the body.

  3. Will new strains of influenza virus circulate this season?

    Influenza viruses are constantly changing, so it is not unusual for new strains of influenza virus to emerge each year. For more information on how flu viruses change, visit “How the flu Virus Can Change”:

    This year's influenza vaccines were made using the following strains:

    • A/California/07/2009 (H1N1)pdm09 -like virus
    • A/ Switzerland/9715293/2013(H3N2)-like virus
    • B/Phuket/3073/2013 like virus (This is a B/Yamagata lineage virus)
    • B/Brisbane/60/2008-like virus (This is a B/Victoria lineage virus. For the quadrivalent influenza vaccine)

    The A/ Switzerland/9715293/2013(H3N2) and B/Phuket/3073/2013 are changes from last year's formulation.

  4. How does influenza spread?
    Influenza usually spreads from person-to-person through aerosolized respiratory droplets released when a person coughs, sneezes, or talks and the droplets then get into a nearby person’s mouth, nose or possibly inhaled into their lungs. Less frequently, people may become infected with influenza by touching something contaminated with the virus and then touching their mouth, nose, or eyes.

  5. What should I do if I am infected with the influenza virus?

    If your flu symptoms are mild, you should stay home and avoid contact with others. Getting plenty of rest, drinking fluids, and avoiding alcohol and tobacco will help your body to fight off the illness more quickly. If you use over-the-counter medications to relieve symptoms, it is important to follow the manufacturer's instructions. Protect others by covering your mouth when coughing and sneezing, wash your hands frequently, and stay at home while you are feeling ill.

    If you are in a high risk group and have symptoms, or you are very sick or worried about your illness, contact your health care provider.

  6. Who is at high risk for developing flu related complications?

    Children younger than 5 but especially children younger than 2 years of age, adult 65 years and older, pregnant women and individuals with various chronic medical conditions are at greatest risk for hospitalization and possibly death related to infection.p>

    A full list of high-risk conditions can be found at:


  1. Why do I need to be immunized against influenza every year?
    Circulating influenza virus strains change from year to year and these changes happen often enough that your immune system doesn’t recognize the flu virus each year. Protection that develops after a person is infected or immunized against the circulating viruses of one season does not provide adequate cross-protection when a new influenza strain develops. That is why you need to get a new flu vaccine each year.

  2. What is the best way to protect myself and my family from getting influenza if we are not vaccinated?
    Vaccination is your best protection against influenza infection. If you are unable to receive the vaccine, avoid close contact with people sick with the flu. Wash your hands often with soap and water or if that is unavailable use alcohol-based hand sanitizer. To prevent the spread of germs, avoid touching your eyes, nose, or mouth and cover your mouth and nose with a tissue when coughing or sneezing.

  3. When should I get vaccinated?
    It is recommended that people get vaccinated against influenza as soon as vaccine becomes available, before flu season, to give the body a chance to build up immunity to the virus. Even though it’s best to get vaccinated as soon as the flu vaccine is available, getting the vaccine later can still be beneficial. Vaccinations should occur through the entire influenza season which ends when product expires in early summer or supply is exhausted.

  4. Where can I receive my vaccine?
    The influenza vaccine can be received from many MTF's and clinics within DoD. To find a clinic near you, use the IHB clinic finder found at

    Additionally, the TRICARE Management Activity issued the final rule authorizing TRICARE retail network pharmacies to administer seasonal influenza at no cost to beneficiaries the for the 2015-2016 influenza season. Service members who receive the influenza vaccination from non-military facilities must provide appropriate immunization data to their unit's point of contact NLT COB of the next duty day following vaccination in order to properly document the annual requirement.