Flu is a contagious respiratory illness caused by influenza viruses that infect the respiratory tract. Flu illness can be mild to severe and in some cases may even cause death. Although anyone can become infected with flu, people 65 years and older, young children, and people with other health conditions are at higher risk for hospitalization and complications from flu. The best way to reduce the risk of flu and its complications is by getting vaccinated every year.
Frequently Asked Questions
- What are the signs and symptoms of influenza?
Symptoms usually include:
- Sore throat
- Muscle aches
- Diarrhea and nausea occasionally in children
Symptoms usually start about 1-4 days after being exposed and can last 2-7 days. Complications may include pneumonia, hospitalization and death.
- How does influenza spread?
Flu is spread from close contact with persons who are sick with flu or from touching surfaces or objects that have flu virus on them. Infection can occur when flu viruses contact the eyes, mouth, or nose, and through breathing in droplets from a sneeze or cough.
People may be able to spread the virus to others about one day before they show symptoms and up to seven days after becoming sick. That means that you may be able to spread the flu to someone else before you even know you are sick, as well as while you are sick.
- Who is at risk for influenza infection?
In the United States, on average 5% to 20% of the population gets the flu and more than 200,000 people are hospitalized from seasonal flu-related complications. Some people, such as older people, young children, pregnant women, and people with certain health conditions, are at high risk for serious flu complications. These health conditions include:
- Neurological and neurodevelopmental conditions
- Chronic lung disease
- Heart disease
- Blood disorders
- Endocrine disorders (i.e., diabetes)
- Kidney and liver disorders
- Metabolic disorders
- Weakened immune systems due to medication or disease, such as HIV/AIDS
- People younger than 19 years of age receiving long-term aspirin therapy
- People who are morbidly obese
- How do I know if I have influenza?
A health care professional may be able to diagnose a flu infection by looking at your symptoms. Sometimes your nose will be swabbed and tested for the influenza virus.
- How is influenza treated?
Most people with flu have mild symptoms and do not need medical care or antiviral medication. Fever-reducing medicine, cough drops for a sore throat or cough, water, and plenty of rest are typically what people with mild symptoms are prescribed.
However, if you have symptoms of flu and are at an increased risk for complications or are very sick, a healthcare provider can prescribe antiviral medication if diagnosed at the beginning of illness onset. Antiviral therapies include, oseltamivir, zanamivir, peramivir, or baloxavir marboxil.
- How is influenza prevented?
The best way not to get flu is to get a flu shot every year before the flu season starts.
Since flu viruses change over time, it is important to get a shot each year. Each year the vaccine is remade to include the types of flu viruses scientist think will be around to cause illness during the flu season. The vaccine begins to protect you within a few days after you get the flu shot, but the vaccine is not fully effective until about 14 days after the shot.
Good respiratory hygiene is important to prevent the spread of all respiratory infections, including the flu:
- Use your elbow or upper arm, instead of your hands, or a tissue to cover your mouth and nose or when you cough or sneeze. Immediately throw used tissues into the trash can. Try not to touch your eyes, nose, or mouth. Many diseases often spread this way. *
- Clean your hands after coughing or sneezing. Wash with soap and water, or clean with alcohol-based hand cleaner if water is not available.
- Avoid close contact with people who are sick.
- If you get flu, stay home from work, school, and social gatherings. This will help others from catching your illness and gives your body the rest it needs to get better.
Information for the Public
- Communicable Disease Reference Guide for Schools: 2023 Edition
- Seasonal Flu Information for Schools and Childcare Providers
Fairs and Farms
- Indiana State Board of Animal Health Avian Influenza Updates
- Information for People with Exposure to Pigs
- Prevent the Spread of Flu Between People and Pigs at Fairs
- 4-H Fair Signage
- Issues for Fair Organizers to Consider When Planning Fairs
- Key Facts for People Exhibiting Pigs at Fairs
- How to Stay Healthy at an Animal Exhibit
Information for Clinicians
- Antiviral Drugs
- Clinical Description & Lab Diagnosis of Influenza
- Infection Control in Health Care Facilities
- Interim Guidance for Influenza Outbreak Management in Long-Term Care Facilities
- Prevention Strategies for Seasonal Influenza in Healthcare Settings
- Seasonal Influenza Vaccination Resources for the Health Professionals
- Type of Influenza Viruses
Laboratory Specimen Information
- Sign up for electronic lab submission through LIMSNET
- Specimen Collection and Transportation Instructions
Long-Term Care Facilities
- Interim Guidance for Influenza Outbreak Management in LTC Facilities
- LTC Facility Respiratory Outbreak Toolkit
- LTC Facility Health Care Personnel Influenza Vaccination Toolkit
Outpatient influenza-like-illness (ILI) Sentinel Surveillance Network (ILINet) is a surveillance program with participating healthcare providers from outpatient healthcare settings. Data reported by the sentinel providers is used to determine the burden of influenza in the state.