What is Influenza ("Flu")?
Influenza is an infection caused by a virus that affects the upper and lower respiratory systems. The symptoms are usually fever, chills, body aching, sore throat, and cough. There are two main types of influenza viruses, Influenza A and B. Within each main type there are many sub-types. All the influenza viruses cause the same general type of symptoms. Different types will be more common in different years or in different countries. In the United States, influenza activity generally peaks between late December to March.
What is the Vaccine?
There are two types of vaccine. Injectable and nasal spray. This information applies to the injectable one. The injectable vaccine is made from inactivated virus. The vaccine does not cause the flu. It works by raising the body's immunity toward the specific viruses that are contained in the vaccine. Influenza viruses are always changing. The vaccine is updated yearly to protect against the viruses predicted to be present in that flu season. The vaccine is quite effective against infection and if a vaccinated person should become infected, the illness will be milder. There is also a live attenuated vaccine which is administered as a nasal spray. It takes about two weeks after the vaccine before it is effective, and the immunity lasts at least six months.
Why Get the Vaccine?
For most people, a bout with the flu will mean three or four days of missing work and feeling generally miserable. Getting the vaccine will help avoid that misery and lost time from work and family. There are certain types of people for whom the flu may mean serious illness. For these people, getting the vaccine may mean the difference between life and death.
Who Should Get the Vaccine?
(This information refers to adults. Please ask your healthcare provider for information regarding children and flu vaccine.)
The vaccine is useful for any adult who wants to decrease their chance of getting influenza. It is especially important for people who may get more seriously ill with flu. The following adults are at risk for severe illness and should be vaccinated:
- Persons 50 years old and older (during influenza epidemics most of the deaths have occurred in the elderly)
- Residents of nursing homes or other chronic care facilities
- People with heart and lung problems (for example, asthma, heart disease, emphysema, chronic bronchitis)
- People with chronic diseases such as diabetes, kidney dysfunction, and sickle cell disease
- People with diseases that affect the immune system, such as AIDS and cancer or are taking medications that suppress immune function
- Women who will be pregnant during the influenza season
- People who can spread influenza to those at high risk such as caregivers/healthcare workers
- Anyone who wants to reduce the risk of becoming ill with influenza or transmitting disease to others
- Persons who have any condition that can compromise respiratory function or handling of respiratory secretions
- Household contacts and caregivers for children less than 5 years old and high risk adults
Healthcare workers are a particularly important group for vaccination for two reasons:
- Healthcare workers can transmit the infection to their patients who may become seriously ill.
- Since healthcare is an essential community service, healthcare workers need to minimize absences from work.
Who Should Not Get the Vaccine?
The vaccine is made using eggs as a means of growing the virus. Therefore, people who are highly allergic to eggs and chicken should not receive this vaccine. The vaccine is preserved with thimerosal. People allergic to thimerosal may get a local reaction from the vaccine. If you have a fever or a significant infection it may be best to wait and have the vaccine after you are over the acute illness, but minor illnesses are not a reason to delay immunization. The vaccine is considered safe for women in any stage of pregnancy but we recommend that pregnant women, especially those in the first trimester, discuss vaccination with their personal health care provider. Individuals with a past history of Guillain Barre Syndrome should discuss vaccination with their healthcare provider.
Are There Side Effects to the Vaccine?
Typically, there are no side effects to the influenza vaccine. However, some people may experience mild side effects such as low-grade fever, tiredness, and soreness at the injection site. The vaccine does not cause the flu.
How is Influenza Spread?
Influenza viruses are present in the respiratory secretions of sick people and can be spread when a sick person coughs or sneezes and the next person breathes in the air that may contain droplets from the cough or sneeze. The virus can persist in dried mucous, so hand washing, not sharing towels with people, and disposing of used tissues, etc. is very important in reducing spread. You can also reduce the risk of spreading the flu by following these healthy habits:
- Cover your mouth and nose when you cough
- Clean your hands often; use hand sanitizers if soap and water is not available
- Avoid touching your eyes, nose and mouth
- Visit the CDC's website for more tips on avoiding spreading illness
What Should I Do if I Get the Flu?
Most people who get influenza will have a fairly mild illness with fever, body aches, and cough. If you have these symptoms, we recommend you take acetaminophen (Tylenol is a brand name of acetaminophen) or one of the over-the-counter brands of ibuprofen. These medications will reduce fever and lessen the body aches. Cough medicine, throat lozenges, or gargling with salt water may be useful for the cough and sore throat. Drink plenty of fluids which will help keep the throat secretions loose and will keep you from becoming dehydrated. If you develop a fever above 101 degrees, chest pain, shortness of breath, severe ear pain, or the material you cough up becomes brown or rusty, you should seek advice from a health care provider. If you are a smoker, it is very important not to smoke while you are ill. Of course, we recommend stopping smoking altogether since smoking increases your chances of getting a cold or lung infection and can make any lung infection more severe.
There are medications that may be taken to prevent or treat influenza. Unlike the vaccine, the medication is taken once an epidemic has started or within 48 hours of symptoms. The medication can either prevent the infection or decrease the severity of the symptoms. Your healthcare provider can advise you about the use of these antiviral medications.