- What is influenza?
- How can I prevent the flu?
- Are there any medications I can take to prevent the flu?
- How does the Flu spread?
- What can I do to protect myself against the flu?
- What are some habits I can develop to have good health?
- If I got a flu vaccine last year, will that protect against the flu this year?
- Why should I get vaccinated against the flu?
- When should I get a flu vaccination?
- What kind of flu vaccines are there?
- Why do I need to get vaccinated against the flu every year?
- Can I get the flu even though I got a flu vaccine this year?
- If I got the flu last year, will I have immunity against the flu this year?
- How do flu vaccines work?
- What should I do if I get sick with the flu?
- What symptoms might I have with the flu?
- What are the risks or complications caused by the flu?
- How do I find out if I have the Flu?
- How should flu be treated?
- Are there emergency warning signs to watch for when I have the flu?
- When is Flu Season in the United States?
- How many people get sick or die from the Flu every year?
A: Influenza (flu) is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness, and at times can lead to death. While most healthy people recover from the flu without complications, some people, such as older people, young children, and people with certain health conditions, are at high risk for serious complications from the flu.
A: The single best way to prevent the flu is to get a flu vaccine each fall, but there are other measures that can help protect against the flu.
A: Antiviral Medications
Three antiviral drugs (amantadine, rimantadine, and oseltamivir) are approved for use in preventing the flu. These are prescription medications, and a doctor should be consulted before they are used.
A: The main way that influenza viruses are spread is from person to person in respiratory droplets of coughs and sneezes. (This is called "droplet spread.") This can happen when droplets from a cough or sneeze of an infected person are propelled (generally up to 3 feet) through the air and deposited on the mouth or nose of people nearby. Though much less frequent, the viruses also can be spread when a person touches respiratory droplets on another person or an object and then touches their own mouth or nose (or someone else's mouth or nose) before washing their hands.
A: By far, the single best way to prevent the flu is for individuals, especially people at high risk for serious complications from the flu, to get a vaccination each fall. However, there are other good health habits that can help prevent the flu. These are:
- Avoid close contact with people who are sick. When you are sick, keep your distance from others to protect them from getting sick too.
- 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 with a tissue when coughing or sneezing. It may prevent those around you from getting sick.
- Washing your hands often will help protect you from germs.
- 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.
A: These steps may help prevent the spread of respiratory illnesses like the flu:
- Cover your nose and mouth with a tissue when you cough or sneeze - throw the tissue away after you use it.
- Wash your hands often with soap and water, especially after you cough or sneeze. If you are not near water, use an alcohol-based hand cleaner.
- Stay away as much as you can from people who are sick.
- If you get the flu, stay home from work or school. If you are sick, do not go near other people so that you don't make them sick too.
- Try not to touch your eyes, nose, or mouth. Germs often spread this way.
A: Vaccination last year is unlikely to protect against influenza this year because a person's immunity after influenza vaccination declines over the year. This is one reason why it is recommended that people get vaccinated every year.
A: Influenza is a serious disease, and people of any age can get it. In an average year, the flu causes 36,000 deaths (mostly among those aged 65 years or older) and more than 200,000 hospitalizations in the United States. The "flu season" in the United States is usually from November through April each year. During this time, flu viruses are circulating in the population. An annual flu vaccine (either the flu shot or the nasal-spray flu vaccine) is the best way to reduce the chances that you will get the flu.
A: Beginning each September, the flu shot should be offered to people at high risk when they are seen by health-care providers for routine care or as a result of hospitalization.
The best time to get vaccinated is from October through November. Flu activity in the United States generally peaks between late December and early March.
You can still benefit from getting vaccinated after November, even if flu is present in your community. Vaccine should continue to be offered to unvaccinated people throughout the flu season as long as vaccine is still available. Once you get vaccinated, your body makes protective antibodies in about two weeks.
A: There are two types of vaccines that protect against the flu. The "flu shot" is an inactivated vaccine (containing killed virus) that is given with a needle, usually in the arm. A different kind of vaccine, called the nasal-spray flu vaccine (sometimes referred to as LAIV for Live Attenuated Influenza Vaccine), was approved in 2003. The nasal-spray flu vaccine contains attenuated (weakened) live viruses, and is administered by nasal sprayer. It is approved for use only among healthy people between the ages of 5 and 49 years. The flu shot is approved for use among people over 6 months of age, including healthy people and those with chronic medical conditions.
Each of the two vaccines contains three influenza viruses, representing one of the three groups of viruses circulating among people in a given year. Each of the three vaccine strains in both vaccines – one A (H3N2) virus, one A (H1N1) virus, and one B virus – are representative of the influenza vaccine strains recommended for that year. Viruses for both vaccines are grown in eggs.
A: Flu viruses change from year to year, which means two things. First, you can get the flu more than once during your lifetime. The immunity (natural protection that develops against a disease after a person has had that disease) that is built up from having the flu caused by one virus strain doesn't always provide protection when a new strain is circulating. Second, a vaccine made against flu viruses circulating last year may not protect against the newer viruses. That is why the influenza vaccine is updated to include current viruses every year.
Another reason to get flu vaccine every year is that after you get vaccinated, your immunity to the disease declines over time and may be too low to provide protection after one year.
A: Yes. The ability of flu vaccine to protect a person depends on two things: 1) the age and health status of the person getting the vaccine, and 2) the similarity or "match" between the virus strains in the vaccine and those in circulation.
A: In general, a person who is infected with an influenza virus one year will have some immunity to closely related viruses that may persist for one or more years. For example, if someone was infected with the Fujian strain of H3N2 that predominated last season, they are likely to have some natural immunity that will give them protection if they are exposed to that strain or a closely related strain again this season. The degree of protection depends on the health of the person involved. Young and healthy people with normal immune systems will likely have good immunity against the same or related strains of virus from one year to the next. However, people with chronic health problems or weakened immune systems are less likely to have immunity from year to year.
It's important to remember that there are different types of influenza viruses circulating and different variants within virus types, and the same type of flu virus does not necessarily circulate each year. For instance, during the 2003-04 flu season, influenza A (H3N2) viruses predominated; however, infection with an influenza A (H3N2) virus would not provide protection against influenza B or influenza A (H1N1) viruses.
A: Both flu vaccines (the flu shot and the nasal-spray flu vaccine (LAIV)) work in the same way; they cause antibodies to develop in the body, and these antibodies provide protection against influenza virus infection.
A: There are steps you can take if you get sick with the flu.
If you are at high risk from complications of the flu, you should consult your health-care provider if you develop flu-like symptoms. Those at high risk for complications include people 65 years or older, people with chronic medical conditions, pregnant women and young children. Your doctor may recommend use of an antiviral medication to help treat the flu.
Other Ways to Respond to the Flu
If you get the flu, get plenty of rest, drink a lot of liquids, and avoid using alcohol and tobacco. Also, you can take medications to relieve the symptoms of the flu (but never give aspirin to children or teenagers who have flu-like symptoms, particularly fever).
Four antiviral drugs (amantadine, rimantadine, zanamavir, and oseltamivir) are approved for treatment of the flu. These are prescription medications, and a doctor should be consulted before the drugs are used. Antiviral treatment lasts for 5 days and must be started within 2 days of illness so if you get flu-like symptoms, seek medical care early on.
- Fever (usually high)
- Tiredness (can be extreme)
- Sore throat
- Runny or stuffy nose
- Body aches
- Diarrhea and vomiting also can occur but are more common in children
A: Some of the complications caused by the flu include bacterial pneumonia, dehydration, and worsening of chronic medical conditions, such as congestive heart failure, asthma, or diabetes. Children may get sinus problems and ear infections as complications from the flu. Those aged 65 years and older and persons of any age with chronic medical conditions are at highest risk for serious complications of flu.
A: It is very difficult to distinguish the flu from other viral or bacterial causes of respiratory illnesses on the basis of symptoms alone. A test can confirm that an illness is influenza if the patient is tested within the first two to three days after symptoms begin. In addition, a doctor's examination may be needed to determine whether a person has another infection that is a complication of influenza.
- Drink plenty of liquids
- Avoid using alcohol and tobacco
- Take medication to relieve the symptoms of flu (but never give aspirin to children or teenagers who have flu-like symptoms – and particularly fever – without first speaking to your doctor.)
In some cases, your doctors may choose to use certain antiviral drugs to treat the flu. (Influenza is caused by a virus, so antibiotics [like penicillin] don't work to cure it.)
A: There are some "emergency warning signs" that require urgent medical attention.
In children, emergency warning signs that need urgent medical attention include:
- Fast breathing or trouble breathing
- Bluish skin color
- Not drinking enough fluids
- Not waking up or not interacting
- Being so irritable that the child does not want to be held
- Flu-like symptoms improve but then return with fever and worse cough
- Fever with a rash
In adults, emergency warning signs that need urgent medical attention include:
- Difficulty breathing or shortness of breath
- Pain or pressure in the chest or abdomen
- Sudden dizziness
- Severe or persistent vomiting
Seek medical care immediately (call your doctor or go to an emergency room) if you or someone you know is experiencing any of the signs above. When you arrive, tell the reception staff that you think you have the flu. You may be asked to wear a mask and/or sit in a separate area to protect others from getting sick.
A: In the United States, the peak of flu season can occur anywhere from late December through March. The overall health impact (e.g., infections, hospitalizations, and deaths) of a flu season varies from year to year. CDC monitors circulating flu viruses and their related disease activity and provides influenza reports each week from October through May.
A: Each flu season is unique, but it is estimated that, on average, approximately 5% to 20% of U.S. residents get the flu, and more than 200,000 persons are hospitalized for flu-related complications each year. About 36,000 Americans die on average per year from the complications of flu.