Flu Influenza Risk

Different people have different risks of catching viruses—particularly the flu. This risk depends on a variety of factors, including your proximity to others who could be sick, your age and your current health.

During this 2009 flu season, the influenza H1N1 virus (“swine flu”) is affecting many people around the world, along with the normal influenza strains. Anyone can get the flu, but who is the most at risk of getting the flu and having flu complications?

Groups with Greatest Flu Risk of Complications

The Centers for Disease Control (CDC) recommends certain groups of people get flu shots as early as possible, because they are at high risk of becoming infected. These groups include:

  • Children aged 6 months to 5 years old
  • Health care workers
  • Household contacts of person at high risk for complications from influenza
  • Household contacts and out-of-home caregivers of children less than 6 months of age
  • People 50 years of age and older
  • People of any age with certain chronic health conditions (such as asthma, diabetes, or heart disease)
  • People who live in nursing homes and other long-term care facilities
  • Pregnant women.

The list above includes groups that may come into contact with the influenza virus often or groups that have weaker immune systems. However, the CDC warns against giving the vaccine to the following groups:

  • Children less than 6 months of age
  • People who have a severe allergy to chicken eggs
  • People who have had a severe reaction to an influenza vaccination
  • People who have a moderate to severe illness with a fever (they should wait until they recover first).

Complications of the Flu

Having the flu makes one weak and vulnerable to a number of complications. If you don’t have a sufficient immune system to combat against these complications—either because of your age or your health—you’re at high risk for both catching and becoming very sick from the flu. The most common complications of the flu include:

  • Bacterial or viral pneumonia
  • Central nervous system infections
  • Dehydration
  • Myositis
  • Pericarditis
  • Side effects from flu medications.

Pneumonia, caused by bacteria or viruses, is probably the most common and serious flu complication.

Age, Pneumonia and Influenza Risk

In past flu seasons, most serious cases of flu and flu-related pneumonia occurred in those 65 years or older. Experts recommend that those in this age group have an additional pneumococcal vaccine.

However, this flu season, those younger than 65 years of age are much more vulnerable to H1N1. This means that they are now more susceptible to having pneumonia complications. H1N1 influenza is linked to the recent rise in bacterial pneumonia cases. The CDC is now urging adults in the high-risk groups (as described earlier) to get vaccinations for the seasonal flu, H1N1 flu, and pneumococcus.


Centers for Disease Control and Prevention staff. (2009). Seasonal flu (influenza)- Vaccination: Summary for clinicians. Retrieved November 30, 2009, from the CDC Web site: http://www.cdc.gov/Flu/professionals/vaccination/vax-summary.htm.

CNN staff. (n.d.) H1N1/Bacterial pneumonia. Retrieved November 30, 2009, from the CNN Web site: http://www.cnn.com/2009/HEALTH/11/26/h1n1. bacterial.pnuemonia/index.html.

WebMD staff. (2009). Cold and flu complications. Retrieved November 30, 2009, from the WebMD Web site: http://www.webmd.com/cold-and-flu/flu-guide/flu-complications.