Influenza (“the flu”) is a respiratory illness caused by the influenza virus. Seasonal influenza illness is typically caused by influenza A virus subtypes H1N1 or H3N2, or by influenza B or C viruses. Influenza A and B viruses cause yearly epidemics—typically in the winter months—in the Northern Hemisphere. Most people with influenza illness recover on their own in about 5-7 days; however, some individuals develop serious complications or die from influenza.

An influenza-associated pediatric death is a death in a child under 18 years of age resulting from a clinically compatible illness that is confirmed to be influenza by an appropriate laboratory or rapid diagnostic test. Influenza-associated pediatric mortality is reportable by law to the health department. Influenza deaths in other age groups are not reportable in Texas.

Yes, influenza is very contagious.  Most healthy adults who are ill with influenza may be able to infect other people beginning 1 day before symptoms develop and up to 5 to 7 days after becoming sick. Children and persons with weakened immune systems might be able to infect other for even a longer period of time.  The virus can also be spread by people who are infected but have no symptoms.

Influenza viruses can be spread by large respiratory droplets generated when an infected person coughs or sneezes 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 door knob), and then touches his or her own nose or mouth.

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
• Headache
• Tiredness (can be extreme)
• Muscle or body aches

Among children, otitis media (ear infection), nausea, vomiting, and diarrhea are common. Some persons who are infected with the influenza virus do not have symptoms.

Most people who develop influenza illness will recover on their own with bed rest and do 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.

Anyone can get sick with influenza. It is estimated that approximately 5%-20% of the population gets the flu each year. Some people are more likely to develop complications from their influenza illness, leading to hospitalization or even death. People who seem to be at higher risk for complications from the flu include:

• Children < 5 years of age, especially children < 2 years of age
• Adults aged 65 years or older
• Pregnant women
• American Indians and Alaskan Natives
• Persons with certain medical conditions including asthma, neurological and neurodevelopmental conditions, chronic lung disease, heart disease, diabetes and other endocrine disorders, liver or kidney disorders, blood disorders, and metabolic disease
• Persons with a weakened immune system (e.g., HIV/AIDS, cancer, chronic corticosteroid treatment)
• People younger than 19years of age who are receiving long-term aspirin therapy
• Persons who are morbidly obese

Healthy individuals exposed to someone with influenza should monitor themselves for a few days to see if they develop symptoms. If symptoms develop, these individuals will usually recover on their own without medical treatment. Individuals at higher risk of complications who have close contact with someone with influenza should contact their medical provider as soon as possible after exposure. The medical provider will determine whether antiviral medications should be given to prevent disease.

Most people will get sick within 1 to 4 days after exposure to the virus; however, some people will not develop symptoms.

A new influenza vaccine is available each year, typically beginning in August or September. The influenza vaccine has three components: an influenza A (H1N1) strain, an influenza A (H3N2) strain, and an influenza B strain. Yearly influenza vaccination is recommended for all persons 6 months of age and older. Persons should seek vaccination as early as possible because once vaccinated, it takes about two weeks for the body to mount a protective immune response. That said, it is never too late in  to get an influenza vaccine because influenza viruses circulate year-round. Getting a flu vaccine every year is the best way to prevent influenza and related complications.

In Texas, most individual cases of influenza are not reportable by law to the health department; however, deaths from influenza in children under the age of 18 years (i.e., influenza-associated pediatric deaths) are reportable within one working day. Influenza outbreaks and infections with variant or novel influenza strains are also reportable. All proven or suspected influenza-associated pediatric deaths, outbreaks, and variant or novel influenza cases are investigated by the health department.

Ill children and adults should stay home and away from well persons until they are fever free for at least 24 hours without the use of fever-reducing medications.

General steps you can take to avoid influenza illness include:

• Get vaccinated for influenza every year
• Wash hands frequently with soap and water, especially after coughing or sneezing
• Use alcohol-based hand sanitizers when facilities are not available for hand washing
• Cover coughs and sneezes with disposable tissues or your arm/sleeve
• Avoid touching your eyes, nose, or mouth
• Avoid close contact with people who are sick
• When you are sick, limit contact with others and stay home until fever free for 24 hours without the use of fever-reducing medications
• Take antiviral medications if prescribed by your doctor