IDCU HomeInfectious Diseases A-CD-GH-LM-QR-ST-ZIDCU Health TopicsDisease ReportingRelated Rules & RegulationsImmunization BranchAbout IDCURelated DSHS SitesStaff Contact List
  • Loading...
    Contact Us

    Infectious Disease Control Unit
    Mail Code: 1960
    PO BOX 149347 - Austin, TX 78714-9347
    1100 West 49th Street, Suite T801
    Austin, TX 78714

    Phone: 512 776 7676
    Fax: (512) 776-7616





Home      Data      Reporting      Investigation      Immunization      Resources

What causes influenza (flu)?

There are two main types of influenza viruses, type A and type B, that cause influenza in humans. 

What are the symptoms of influenza?

Influenza usually comes on suddenly, one to four days after the virus enters the body, and may include these symptoms:

Fever or feeling feverish/chills

• Cough

Runny or stuffy nose

Sore throat


Tiredness (can be extreme)

Muscle or body aches

Among children, otitis media, nausea, vomiting, and diarrhea are common. Some infected persons are asymptomatic.

When can a person spread influenza to another person?

A person can start spreading the influenza virus to other people one day before symptoms and up to a week (7 days) after becoming sick. There are people that could spread the influenza virus for a longer period of time.   

When is the “official” influenza season?

Most influenza activity usually occurs from October to May in the United States even though influenza viruses have been detected year round.

A new influenza season begins the first week of October and goes through the third week in May.  However, Texas conducts influenza surveillance year around.     

Do other respiratory viruses circulate during the flu season?

There can be other respiratory viruses that circulate during the flu season and can cause similar symptoms and illness as influenza.  Some other respiratory viruses that may circulate during influenza season include:

  • Rhinovirus,
  • Respiratory Syntical Virus (RSV),
  • Adenovirus, and
  • Parainfluenza

Why should people get vaccinated against the flu?

Influenza is a serious disease that can lead to hospitalization and sometimes death. Every flu season is different, and influenza infection can affect people differently. Even healthy people can get very sick from the flu and spread it to others.  According to the Centers for Disease Control and Prevention (CDC), an estimated 23,607 (range 3,349-48,614) influenza-associated deaths and over 200,000 influenza-associated hospitalizations occur every year in the United States.  

During “flu season”, flu viruses are circulating at higher levels in the U.S. population. An annual seasonal flu vaccine (either the flu shot or the nasal spray flu vaccine) is the best way to reduce the chances that you will get seasonal flu and spread it to others. When more people get vaccinated against the flu, less flu can spread through that community.

Who should get vaccinated this season?

All persons aged 6 months and older are recommended for annual vaccination, with rare exception.  There is special consideration regarding people that have an egg allergy.

People who have ever had a severe allergic reaction to eggs can get recombinant flu vaccine if they are 18 years and older or they should get the regular flu shot (IIV) given by a medical doctor with experience in management of severe allergic conditions. People who have had a mild reaction to egg—that is, one, which only involved hives—may get a flu shot with additional safety measures. Recombinant flu vaccines also are an option for people if they are 18 years and older and they do not have any contraindications to that vaccine. Make sure your doctor or health care professional knows about any allergic reactions. Most, but not all, types of flu vaccine contain a small amount of egg.   

Who Should Not Be Vaccinated?

These group of people should not get the flu shot:

  • Children younger than 6 months are too young to get a flu shot
  • People with severe, life-threatening allergies to flu vaccine or any ingredient in the vaccine. This might include gelatin, antibiotics, or other ingredients

What viruses are included in the 2015-2016 influenza vaccine?

All 2015-2016 influenza vaccine is made to protect against the following three viruses:

  • A/California/7/2009 (H1N1)pdm09-like virus,
  • A/Switzerland/9715293/2013 (H3N2)-like virus, and
  • B/Phuket/3073/2013-like virus (this is a B/Yamagata lineage virus)

Some of the 2015-2016 flu vaccine is quadrivalent vaccine and protects against an additional B virus (B/Brisbane/60/2008-like virus). This is a B/Victoria lineage virus.

Who is the DSHS Central Office Influenza Surveillance Team?

The members of the DSHS Influenza Surveillance Team are:

Johnathan Ledbetter

Epidemiologist / Influenza Surveillance Coordinator


Robert “Bob” Russin

ILINet Coordinator


Lesley Brannan

Epidemiologist / Respiratory Team Lead


Where can people find influenza data besides the DSHS Influenza webpages?

People may find influenza data at the following webpages: 

World Health Organization

Centers for Disease Control and Prevention

Department of Defense:



  • Loading...
Last updated July 08, 2015