Feature Stories

Flu Vaccine Facts

Two UM experts address flu vaccine benefits, prevention tips, common misconceptions and much more

Ask the Expert

Get answers to your H1N1 (Swine) flu questions.

Note: This is for informational purposes only. Doctors cannot provide a diagnosis or individual treatment advice via e-mail. Please consult your physician about your specific health care concerns.

Related Content

Every winter it's a fact of life--the headache, dry cough, body aches, fever and sore throat that signal the onset of the flu. Each year 5 to 20 percent of the population gets hit with the influenza virus and more than 200,000 people are hospitalized with flu complications, according to the Centers for Disease Control and Prevention (CDC). But preventive measures can be taken in the simple form of a flu vaccine.

"One of the most important public health measures in preparation for the winter season is influenza vaccination. In effect, you can protect yourself and possibly the people around you," said Wilbur Chen, M.D., a flu vaccine expert and assistant professor of medicine at the University of Maryland School of Medicine.

According to the CDC, flu vaccine manufacturers are projecting that as many as 143 to 146 million doses of influenza vaccine will be produced in the U.S. during the 2008-09 flu season. This is an all-time high supply of vaccine making it possible for more people than ever to seek protection from the flu. The Centers for Disease Control and Prevention has designated the week of December 8-14, as National Influenza Vaccination Week. This event is designed to highlight the importance of flu vaccination, as well as encourage greater use of flu vaccine through the months of December, January and beyond.

In addition to the standard flu shot, FluMist, a nasal flu vaccine, is now available for healthy people between the ages of 2 and 49. But children under 24 months of age, children with asthma, and children under the age of 5 years with recurrent wheezing should not get FluMist.

Who Should be Vaccinated?

According to the CDC, anyone who wants to reduce their chances of getting the flu can get vaccinated. However, certain people should get vaccinated each year--either people who are at high risk of having serious flu complications or people who live with or care for those at high risk. The updated recommendations for vaccination are:

All persons, including school-aged children, who want to reduce the risk of becoming ill with influenza or of transmitting influenza to others.
All children aged 6–59 months (i.e., 6 months–4 years)
All adults 50 years of age or older
Pregnant women
Children and adolescents (aged 6 months–18 years) receiving long-term aspirin therapy
Adults and children who have chronic pulmonary (including asthma), cardiovascular (except hypertension), renal, hepatic,
hematological or metabolic disorders (including diabetes).
Adults and children who have immunosuppression (including immunosuppression caused by medications or by HIV).
Adults and children who have any condition (e.g., cognitive dysfunction, spinal cord injuries, seizure disorders, or other
neuromuscular disorders) that can compromise respiratory function or the handling of respiratory secretions or that can increase the risk for aspiration.
Residents of nursing homes and other chronic-care facilities
Health-care personnel
Healthy household contacts (including children) and caregivers of children under 5 years and adults over 50 years, with
particular emphasis on vaccinating contacts of children under 6 months old.
Healthy household contacts (including children) and caregivers of persons with medical conditions that put them at higher
risk for severe complications from influenza.

But even those who don't fall within these risk groups also benefit from the vaccine.

"People not in the risk groups tend to have milder or shorter duration of illness with influenza. But, vaccination may prevent a person from being a spreader of the flu to others. So when you add up the benefits, people can protect themselves and those around them, especially if they (other people in frequent contact with the person vaccinated) are in the high risk groups," said Chen.

Robert Edelman, M.D., associate director for clinical research at the University of Maryland Center for Vaccine Development and professor of medicine and pediatrics at the University of Maryland School of Medicine, agrees. "With the flu shot you keep yourself protected. It's an insurance policy."

Flu Dangers

If you fall into one of the high-risk groups outlined above, the importance of getting an annual flu shot cannot be overstated. Although most people recover, the CDC estimates that in the U.S., more than 200,000 people are hospitalized and more than 36,000 die from the flu and its complications every year. For the elderly and people with certain chronic illnesses, the flu and its complications can be life threatening.

"The flu in the elderly and people with respiratory conditions puts a tremendous stress into their systems. Some patients can develop respiratory failure and die," Edelman said.

When to Call Your Doctor

Some symptoms may indicate a more serious medical problem than just a simple cold or even the flu. Chen said people who experience any of the following symptoms and are concerned should contact their doctor:

high fever
difficulty breathing
inability to take fluids
prolonged illness

Cold or Flu?

So how do you know if you have the flu or just a common cold? The difference is in the severity and duration of the symptoms.

"With the flu you have severe muscle aches, nausea, sore throat, trouble breathing and a high fever," Edelman said. "It will often put you into bed. The flu has a greater propensity to be more severe and spread more easily."

According to the CDC, flu usually comes on suddenly and may include the following symptoms:

Fever
Headache
Body/muscle aches
Extreme tiredness
Dry cough
Sore throat
Runny or Stuffy Nose
Stomach symptoms, such as nausea, vomiting and diarrhea, can occur but are more common in children than adults.

Colds and flu are both highly contagious and intitially, a bad cold and a mild case of the flu might seem alike. However, unlike colds, influenza is a serious illness that can have life-threatening complications.

Common Flu Misconceptions

Despite the benefits of the flu vaccine, several misconceptions persist. The most common myth is that the flu vaccine can actually give you the flu.

"Many people believe the flu shot can cause the flu," Chen said. "There is no live virus in the vaccine so it truly cannot cause the flu. However, some people do experience one of the common fall or winter viruses shortly after vaccination and will simply mistake those infections for the flu."

Some people are concerned that the side effects of the flu shot may be worse than the flu itself. In reality, only a minority of people experience any side effects from the vaccine; these side effects tend to be mild and of very short duration, according to Chen. "Typically the worst side effect is a sore arm as seen with other needle-using vaccines. Nonetheless, the vaccines are manufactured with chicken eggs, so if a person is allergic to eggs they should not receive the vaccine. Otherwise, for most people, the vaccine has no side effects."

Finally, some people might reason that since the influenza vaccine isn't 100 percent effective, they're better off getting the flu. Even if the vaccine doesn't prevent you from getting the flu, you are still likely to be far less sick than you would have been without the shot. The vaccine also greatly reduces the chance of severe complications.

"It cuts down, eliminates the flu or decreases the severity of the illness," Edelman says. "It dampens it [flu] down so much that you don't get very sick."

When to Get Vaccinated

According to the CDC, yearly flu vaccination should begin as soon as the vaccine is available and continue throughout the influenza season, into December, January, and beyond. Influenza season most often peaks in February, but influenza viruses can continue to cause illness into the spring. If you did not receive your flu vaccine in the fall, vaccination in December, January and beyond is beneficial in most years. Flu season can begin as early as October and last as late as May. Keep in mind that it takes one to two weeks for the flu shot to take effect.

Each September, a new flu vaccine is introduced. The vaccine is approximately 70 to 90 percent effective for healthy adults, according to the CDC. High-risk groups, though, usually don't fare as well. Edelman sites the elderly in particular as a group that receives less protection from the vaccine.

Reduce Your Risk

Of course, the main way to prevent the flu is to get the vaccine. But since the flu is a highly contagious viral respiratory tract infection, you can also reduce your risk by avoiding contact with infected people and frequently washing your hands. The flu is spread by airborne transmission -- sneezing and coughing. But the virus can also live on objects, such as doorknobs, telephone receivers and utensils. Viruses can pass through the air and enter your body through your nose or mouth. You are at greatest risk of getting infected in highly populated areas.

If all else fails and you catch the flu anyway, the general treatment includes resting in bed, drinking plenty of fluids and taking over the counter medicines such as aspirin or acetaminophen. However, do not give aspirin to children and adolescents under 18 who have the flu, and avoid antibiotics because they do not work on viruses.

Several prescription antiviral medicines can help both prevent flu infection and reduce its duration and severity. Chen, though, says when it comes to prevention, the vaccine is hard to beat. "The vaccine is inexpensive, works well, and may cut off the spread of influenza to those around you. Preventing a disease from happening or spreading with a simple vaccine is better than treating a disease once it has occurred."

By Michelle W. Murray

This page was last updated on: October 22, 2009.

For patient inquiries, call 1-800-492-5538 or click here to make an appointment.