Influenza (flu) is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness. Serious outcomes of flu infection can result in hospitalization or death. Some people, such as older people, young children, and people with certain health conditions, are at high risk of serious flu complications.
The best way to prevent the flu is by getting vaccinated each year.
Most people who get the flu will have mild illness, will not need medical care or antiviral drugs, and will recover in less than two weeks. Some people, however, are more likely to get flu complications that can result in hospitalization and sometimes death. Pneumonia, bronchitis, sinus infections and ear infections are examples of flu-related complications. The flu also can make chronic health problems worse. For example, people with asthma may experience asthma attacks while they have the flu, and people with chronic congestive heart failure may experience a worsening of this condition triggered by flu. List below are the groups of people who are more likely to get serious flu-related complications if they get sick with influenza.
People at High Risk for Developing Flu-Related Complications
- Children younger than 5, but especially children younger than 2 years old
- Adults 65 years of age and older
- Pregnant women (and women up to two weeks postpartum)
- Residents of nursing homes and other long-term care facilities
- Also, American Indians and Alaskan Natives seem to be at higher risk of flu complications
People who have medical conditions including:
- Neurological and neurodevelopmental conditions [including disorders of the brain, spinal cord, peripheral nerve, and muscle such as cerebral palsy, epilepsy (seizure disorders), stroke, intellectual disability, moderate to severe developmental delay, muscular dystrophy, or spinal cord injury].
- Chronic lung disease (such as chronic obstructive pulmonary disease [COPD] and cystic fibrosis)
- Heart disease (such as congenital heart disease, congestive heart failure and coronary artery disease)
- Blood disorders (such as sickle cell disease)
- Endocrine disorders (such as diabetes mellitus)
- Kidney disorders
- Liver disorders
- Metabolic disorders (such as inherited metabolic disorders and mitochondrial disorders)
- Weakened immune system due to disease or medication (such as people with HIV or AIDS, or cancer, or those on chronic steroids)
- People younger than 19 years of age who are receiving long-term aspirin therapy
- People with extreme obesity (body mass index [BMI] of 40 or more) Calculate your Body Mass Index or BMI
Note: There is no recommendation for pregnant women or people with pre-existing medical conditions to get special permission or written consent from their doctor or health care professional for influenza vaccination if they get vaccinated at a worksite clinic, pharmacy or other location outside of their physician’s office. For more information, visit Misconceptions about Seasonal Flu and Flu Vaccines.
- CDC recommends a yearly flu vaccine as the first and most important step in protecting against flu viruses.
- While there are many different flu viruses, a flu vaccine protects against the viruses that research suggests will be most common. (See Vaccine Virus Selection for this season’s vaccine composition.)
- Flu vaccination can reduce flu illnesses, doctors’ visits, and missed work and school due to flu, as well as prevent flu-related hospitalizations.
- Everyone 6 months of age and older should get a flu vaccine every year before flu activity begins in their community. CDC recommends getting vaccinated by the end of October, if possible. Learn more about vaccine timing.
- CDC recommends use of injectable influenza vaccines (including inactivated influenza vaccines and recombinant influenza vaccines) during 2017-2018. The nasal spray flu vaccine (live attenuated influenza vaccine or LAIV) should not be used during 2017-2018.
- Vaccination of high risk persons is especially important to decrease their risk of severe flu illness.
- People at high risk of serious flu complications include young children, pregnant women, people with chronic health conditions like asthma, diabetes or heart and lung disease and people 65 years and older.
- Vaccination also is important for health care workers, and other people who live with or care for high risk people to keep from spreading flu to them.
- Children younger than 6 months are at high risk of serious flu illness, but are too young to be vaccinated. People who care for infants should be vaccinated instead.
- Try to avoid close contact with sick people.
- While sick, limit contact with others as much as possible to keep from infecting them.
- If you are sick with flu-like illness, CDC recommends that you stay home for at least 24 hours after your fever is gone except to get medical care or for other necessities. (Your fever should be gone for 24 hours without the use of a fever-reducing medicine.)
- Cover your nose and mouth with a tissue when you cough or sneeze. Throw the tissue in the trash after you use it.
- Wash your hands often with soap and water. If soap and water are not available, use an alcohol-based hand rub.
- Avoid touching your eyes, nose and mouth. Germs spread this way.
- Clean and disinfect surfaces and objects that may be contaminated with germs like the flu.
The pages listed below offer public health and health care professionals key information about vaccination, infection control, prevention, treatment, and diagnosis of seasonal influenza.
- Vaccine Recommendations (ACIP)
- Clinical Evaluation & Diagnosis
- Antiviral Drugs
- Information for Laboratories
- Institutional Outbreaks and Infection Control
- Long-Term Care Facilities
For additional information, visit CDC’s flu website for Healthcare Providers.
- MMWR Week 48 (11/26-12/2/2017)
- MMWR Week 49 (12/3-12/9/2017)
- MMWR Week 50 (12/10-12/16/2017)
- MMWR Week 51 (12/17-12/23/2017)
- MMWR Week 52 (12/24-12/30/2017)
- MMWR Week 1 (12/31/2017-1/6/2018)
- MMWR Week 2 (1/7-1/13/2018)
- MMWR Week 3 (1/14-1/20/2018)
- MMWR Week 4 (1/21-1/27/2018)
- MMWR Week 5 (1/28-2/3/2018)
- MMWR Week 6 (2/4-2/10/2018)
- MMWR Week 7 (2/11-2/17/2018)
- MMWR Week 8 (2/18-2/24/2018)
- MMWR Week 9 (2/25-3/3/2018)
- MMWR Week 10 (3/4-3/10/2018)
- MMWR Week 11 (3/11-3/17/2018)
- MMWR Week 12 (3/18-3/24/2018)
- MMWR Week 13 (3/25-3/31/2018)
- MMWR Week 14 (4/1-4/7/2018)
- MMWR Week 15 (4/8-4/14/2018)
- MMWR Week 16 (4/15-4/21/2018)
- MMWR Week 17 (4/22-4/28/2018)
- MMWR Week 18 (4/29-5/5/2018)
- MMWR Week 19 (5/6-5/12/2018)
- MMWR Week 20 (5/13-5/19/2018)