Influenza (Flu) Fact Sheet
Last Reviewed: October 2013
What Everyone Should Know About Flu and the Flu Vaccine
What is the flu?
The flu is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness, and at times can lead to death. Some people, such as older people, young children, and people with certain health conditions, are at high risk for serious flu complications.
Every year in the United States:
- On average more than 200,000 people are hospitalized from flu complications, and;
- More than 23,600 people die from flu (with a range of 3,349-48,614 people); about 90% of such deaths occur in persons aged 65 years and older.
The best way to prevent this illness is by getting a flu vaccination.
What are the symptoms of the flu?
The flu usually starts suddenly and may include these symptoms:
- Fever* or feeling feverish/chills
- Sore throat
- Runny or stuffy nose
- Muscle or body aches
- Fatigue (tiredness)
- Some people may have vomiting and diarrhea, though this is more common in children than adults
* It's important to note that not everyone with flu will have a fever.
What are the complications associated with the flu?
Some of the complications caused by flu include pneumonia, ear infections, sinus infections, dehydration, and worsening of chronic medical conditions, such as heart or lung disease, asthma or diabetes.
How is the flu spread?
The flu is spread in droplets released by coughing and sneezing. It usually spreads from person to person, though occasionally people may be infected by touching something with virus on it and then touching their eyes, nose, or mouth.
When and for how long is a person able to spread the flu?
You may be able to pass on the flu to someone else before you know you are sick, as well as while you are sick. Most adults may be able to infect others beginning 1 day before symptoms develop and up to 5 to 7 days after becoming sick. Some people, especially young children and people with weakened immune systems, might be able to infect others for an even longer time.
Cold Versus Flu
What is the difference between a cold and the flu?
The flu and the common cold are both respiratory illnesses but they are caused by different viruses. Because colds and flu share many symptoms, it can be difficult (or even impossible) to tell the difference between them based on symptoms alone. Most people who have flu symptoms will not be tested, and do not need to be tested, because test results usually do not change how a patient is treated. Treatment, if decided upon by the health care provider, will usually be based on severity of symptoms and how likely a person is to have complications of flu – not on the basis of a test result.
What are the symptoms of the flu versus the symptoms of a cold?
- The flu tends to start very suddenly, while colds tend to develop gradually.
- The flu is worse than the common cold, and symptoms such as fever, body aches, extreme tiredness and dry cough are more common and intense.
- People with colds are more likely to have a runny or stuffy nose.
- Colds generally do not result in serious health problems, such as pneumonia, bacterial infections, or hospitalizations.
Preventing the Flu
What is the best way to protect myself against the flu?
The single best way to prevent the flu is to get a flu vaccination each fall. There are two types of vaccines:
- The "flu shot" is an inactivated vaccine (containing killed virus) that is given with a needle. It can be given in the muscle or just under the skin. The flu shot that is given in the muscle is approved for use in people older than 6 months, including healthy people and people with chronic medical conditions. The flu shot that is given below the skin is for those 18-64 years of age.
- The nasal-spray flu vaccine is a vaccine (sometimes called LAIV for "Live Attenuated Influenza Vaccine") made with live, weakened flu viruses that do not cause the flu. LAIV is approved for use in healthy people 2 years to 49 years of age who are not pregnant.
Talk to your provider to find out which vaccine is right for you and your family.
About two weeks after vaccination, antibodies develop that protect against flu virus infection for the entire season. Flu vaccines will not protect against illnesses caused by other viruses, such as the common cold.
Who should get the flu vaccine?
Everyone 6 months of age and older should get vaccinated against the flu. Vaccination should begin as soon as the vaccine is available.
Vaccination to prevent flu is particularly important for persons who are at increased risk for severe complications from flu or at higher risk for flu-related outpatient, emergency department, or hospital visits. The list below includes the groups of people more likely to get flu-related complications if they get sick from influenza:
- Children younger than 5, but especially children younger than 2 years of age
- Adults 50 years of age and older, but especially those 65 years of age and older
- Women who are or will be pregnant during flu season
- American Indians and Alaskan Natives
- Residents of nursing homes and other chronic care facilities
- People who have the following medical conditions:
- 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 (mental retardation), moderate to severe developmental delay, muscular dystrophy, or spinal cord injury].
- Chronic lung disease (such as chronic obstructive pulmonary disease [COPD] and cystic fibrosis) and Asthma
- 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 who are morbidly obese (Body Mass Index, or BMI, of 40 or greater)
Vaccination efforts should also focus on delivering vaccine to the following persons:
- Health care personnel;
- Household contacts and caregivers of children younger than 5 years and adults aged 50 years or older, with particular emphasis on vaccinating contacts of children younger than 6 months
Does my child need to receive more than one dose of flu vaccine this season?
Some children aged 6 months through 8 years require two doses of flu vaccine (given a minimum of four weeks apart). Children in this age group who are getting vaccinated for the first time will need two doses. If this is not the first season that your child is receiving flu vaccine, talk with your child's provider to determine how many doses your child needs to protect them from the flu this year.
Who should NOT be vaccinated?
There are some people who should not be vaccinated. They include:
- People who have had a severe reaction to a flu vaccination;
- Children less than 6 months of age.
Some people should wait to get vaccinated until they talk with their provider. They include:
- People who have a severe allergy to chicken eggs;
- People who are sick with a fever. (These people can get vaccinated once their symptoms lessen. People with a mild illness can usually get the vaccine.)
- People who developed Guillain-Barre syndrome (GBS) within six weeks of getting flu vaccine.
What other methods can help prevent the flu?
Although the single best way to prevent seasonal flu is to get vaccinated each year, good health habits often can help stop the spread of germs and prevent respiratory illnesses like the flu.
- Avoid close contact with people who are sick. When you are sick, keep your distance from others to protect them from getting sick too.
- Stay home when you are sick. If possible, stay home from work, school, and errands when you are sick. You will help prevent others from catching your illness.
- Cover your mouth and nose. Cover your mouth and nose with a tissue when coughing or sneezing. If no tissue is available, cough or sneeze into the bend of your arm. It may prevent those around you from getting sick.
- Clean your hands. Washing your hands often will help protect you from germs. If soap and water are not available, use an alcohol-based hand sanitizer that contains at least 60% alcohol to clean your hands.
- Avoid touching your eyes, nose, or mouth. Germs are often spread when a person touches something that is contaminated with germs and then touches his or her eyes, nose, or mouth.
- Practice other good health habits. Clean and disinfect frequently touched surfaces at home, work or school, especially when someone is ill. Get plenty of sleep, be physically active, manage your stress, drink plenty of fluids, and eat nutritious food.
Can the flu be treated?
In certain circumstances, your doctor or health care provider might prescribe antiviral drugs to help reduce the severity and duration of your illness. Antiviral drugs are not sold over-the-counter and are different from antibiotics. You can get them only if you have a prescription from your doctor or health care provider. Your health care provider can help decide whether you should take an antiviral drug, and, if so, which one you should take.
Antiviral drugs are a second line of defense to treat the flu if you get sick. NYSDOH recommends flu vaccination as the first and best way to prevent influenza.