What are complications of the flu?

Complications of influenza can include: dehydration, worsening of chronic medical conditions (i.e., asthma, diabetes, congestive heart failure), and bacterial pneumonia. Children may get sinus and ear infections.

Some people, such as older people, young children, and those with certain health conditions are at higher risk for serious influenza complications. Pregnant women are also more susceptible to serious complications.

What should I know about the flu vaccine?

• The influenza vaccine is changed each year to match the currently circulating type of influenza. The influenza vaccine composition to be used in the 2008–2009 season in the United States is identical to that recommended by the World Health Organization. The trivalent influenza vaccine to be used in 2008–2009 has been changed from the previous season, in order to provide as close a match to the known circulating strains of flu viruses in the most recent flu season.
• One needs an influenza vaccine each year to get the latest protection.

How long does it take to work?

The vaccine stimulates production of antibodies that provide protection against the influenza viruses in the vaccine. Influenza vaccine causes your body to generate protective immunity in about two weeks. The ability of the influenza vaccine to protect a person depends on the health status (immune system especially) and age of the individual, and the “match” or similarity between the virus strains in the vaccine and the circulating influenza strains. Studies have proven that both the influenza shot and the nasal-spray influenza vaccine are effective in preventing the influenza virus.

What about side effects? Can I get the flu from getting a flu shot?

You do not get influenza from the influenza vaccine. Most people will have no side effects from the vaccine. Some people may have coincidental respiratory illness around the time of receiving the influenza vaccine. This is not due to the influenza vaccine, but due to concurrent exposure to other respiratory illness.

Today’s influenza vaccines cause fewer side effects than those used in the past, if any at all. However, some minor side effects can occur: tenderness at the site of the shot may occur and last for several days. Some people (more likely to be people who have not received the influenza vaccine before or who have had no previous exposure to the influenza antigens in that season’s influenza vaccine) may have low grade fever, chills, headache, malaise, or muscle aches within the first 48 hours. These reactions begin 6–12 hours after vaccination and can persist for one to two days. These symptoms are minor compared with influenza and the complications that can accompany influenza. Almost all people who receive influenza vaccine have no serious problems from it.

What else can I do to protect myself and others from the flu?

• Cover your nose and mouth with a tissue when you cough or sneeze, and dispose of the tissue afterward.
• If you do not have a tissue, cough or sneeze into your upper sleeve.
• Clean your hands after you cough or sneeze with soap and warm water or an alcohol-based hand rub, even if your hands are not visibly soiled.
• If you get sick from the influenza virus, avoid exposing others. Stay home from work or school until your fever is gone and you feel ready to resume normal activites.