Influenza viruses are spread from person to person by respiratory droplets generated when an infected person coughs, sneezes, or talks in close proximity to an uninfected person. Sometimes, influenza viruses are spread when a person touches a surface with influenza viruses on it (e.g., a doorknob), and then touches his or her own nose or mouth.

A healthy adult may be able to spread influenza 1 day before symptoms develop and up to 5 to 7 days after they become sick.  Some people, especially young children and people with weakened immune systems, might be able to infect others for an even longer time.

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
• Sore throat
• Runny or stuffy nose
• Headache
• Muscle or body aches
• Tiredness (can be extreme)

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

Most people generally recover from illness in a few days to less than two weeks, but some people develop complications (such as pneumonia) and may die from influenza. The highest rates of influenza infection occur among children; however, the risks for serious health problems, hospitalizations, and deaths from influenza are typically greatest among people 65 years of age or older, children aged <5 years especially those aged <2 years, pregnant women, and people of any age who have medical conditions that place them at increased risk for complications from influenza.

In people with chronic medical conditions such as heart or lung disease, influenza can lead to pneumonia and other life-threatening illnesses. Persons 65 years of age and older account for approximately 90% of deaths attributed to pneumonia and influenza. Young children with influenza can develop high fevers, and a small percentage of children hospitalized with influenza can have febrile seizures. Deaths from influenza are uncommon among children, but do occur. Influenza has also been associated with neurological problems, Reye’s syndrome, muscle inflammation, and heart inflammation.

Most people who develop influenza illness will recover on their own by getting rest and will not need medication. Antiviral medications can shorten the duration and severity of illness if given within the first 48 hours of the illness. These medications are usually prescribed to persons who have a severe illness or to those who are at higher risk for developing serious illness or complications due to influenza.

The best way to prevent influenza is to get an influenza vaccine each year as soon as the vaccine is available to the public. Vaccination is associated with reductions in influenza-related respiratory illness and physician visits among all age groups, hospitalization and death among persons at high risk, otitis media among children, and work absenteeism among adults.

Other forms of prevention include:

• Hand washing and using alcohol-based hand sanitizers,
• Covering your coughs and sneezes with a disposable tissue or your arm or sleeve,
• Avoiding touching your eyes, nose, or mouth,
• Avoiding close contact with persons who are ill,
• Staying home when you are ill, and
• Taking antiviral medications if prescribed by your doctor.   
  • In certain situations (e.g., influenza outbreaks in settings like nursing homes), antiviral medications may be prescribed to high-risk individuals to prevent them from developing influenza illness after exposure to infected individuals.

Children with a fever should be kept out of school or childcare until they are fever free for 24 hours without the use of fever suppressing medications. Rules for exclusion of sick children from school and childcare are outlined in the Texas Administrative Code, specifically Rule 97.7 for schools and Rule 746.3603 for childcare.

The official influenza reporting season for the United States begins in October and continues through May; in Texas, influenza surveillance continues year-round.  Influenza activity usually peaks in January or February in Texas, although the peak of influenza has occurred as early as October. Individual cases of influenza are not required to be reported by law in Texas, with the exception of influenza-associated pediatric deaths and novel influenza cases (influenza A viruses that are subtyped as H2, H5, H7, and H9).

Providers, laboratories, healthcare facilities, and schools are highly encouraged to provide total case counts of influenza-like-illness and positive influenza tests to their local health department or public health region.

Reporting of influenza-associated pediatric deaths began in Texas in 2007. From 2010-2023, the reported number of cases of influenza-associated pediatric mortality ranged from 3 to 24 per year.

Influenza-associated pediatric mortality cases are reportable within one working day.

All influenza-associated pediatric mortality cases should be reported to the local health department or health service region.

Several Texas laws (Tex. Health & Safety Code, Chapters 81, 84 and 87) require specific information regarding notifiable conditions be provided to the Texas Department of State Health Services (DSHS).Health care providers, hospitals, laboratories, schools, and others are required to report patients who are suspected of having a notifiable condition (25 Tex. Admin. Code §97.2 ).

• Investigation Forms
• Influenza (Flu) Health Practitioner Guidance and Training