High-risk groups for the flu

(Updated 11/19/09)

Defining high-risk groups
Who is at most risk for seasonal flu
Who is at most risk for H1N1 flu

Flu viruses can infect anyone, whether it is the current seasonal flu strain, novel influenza A H1N1 (swine flu) or another variety.

However, some groups of people are more at risk for serious complications than other groups are. Different strains of flu viruses may affect certain groups more adversely than other groups.

Two of the more serious strains of flu viruses are the seasonal flu and H1N1 flu. The seasonal flu virus is different each year and the H1N1 may change over time.

High-risk groups for the flu are people that may have more severe complications than the general population. These groups should strongly consider taking steps such as vaccinations to prevent infection.

High-risk groups for H1N1 flu

The virus that causes H1N1 flu is different from the virus that causes seasonal flu. High-risk groups for H1N1 flu differ from the seasonal flu risk groups.

The vaccination recommendations for the H1N1 flu virus are somewhat different from those for the seasonal flu.

The Centers for Disease Control and Prevention's (CDC) Advisory Committee on Immunization Practices (ACIP) has defined the groups of at-risk people who can receive vaccination based on vaccine availability. The Wisconsin Department of Health Services distributes vaccine throughout Wisconsin and expands the high risk groups to include more people when more vaccine is available.

As of 11/23/09, the current high risk groups will receive vaccinations before those at lower risk. These groups include:

Pregnant women
People who live with or care for infants less than 6 months old (examples: parents, siblings, daycare providers)
People 6 months through 24 years of age
Adults ages 25-64 years with underlying medical conditions that put them at risk for influenza-related complications
Health care and emergency medical services personnel who have direct patient care contact

These medical conditions include:

Chronic pulmonary (including asthma) disorders; cardiovascular (except hypertension) disorders; renal (kidney) disorders; hepatic (liver) disorders; cognitive disorders; neurologic and neuromuscular disorders; hematological or metabolic disorders (including diabetes mellitus); immunosuppression (including immunosuppression caused by medications or by human immunodeficiency virus); or receiving long-term aspirin therapy.
Individuals who are obese, particularly those who are morbidly obese, are at increased risk for H1N1- related complications and should be vaccinated as part of the target group. Obesity is defined as body-mass index (BMI) > 30 and morbid obesity is defined as BMI > 40.

People under age 65 not in the target groups will be vaccinated after more vaccine becomes available in the coming weeks.

If a member of your family is in this target group, you should contact your doctor or a Marshfield Clinic location near you.

Current studies indicate the risk for infection among persons age 65 or older is less than the risk for younger age groups. Therefore, as vaccine supply and demand for vaccine among younger groups is being met, vaccination will be offered to people over the age of 65.

This priority list may change as the vaccine supply fluctuates. The CDC continues to stress that there will be adequate H1N1 vaccine supplies available for everyone who wants it. It may take longer than previously projected for adequate supplies to become available.

High risk groups for seasonal flu

The seasonal flu causes more than 36,000 deaths in a typical flu season (roughly fall through spring). In addition, some 200,000 people are hospitalized each year due to complications.

According to the Centers for Disease Control and Prevention (CDC), people who are at the highest risk each year for seasonal flu are:

Children aged 6 months up to their 19th birthday
Pregnant women
People 50 years of age and older
People of any age with certain chronic medical conditions
People who live in nursing homes and other long-term care facilities
People who live with or care for those at high risk for complications from flu, including:

Health care workers
Household contacts of persons at high risk for complications from the flu
Household contacts and out of home caregivers of children less than 6 months of age (these children are too young to be vaccinated)

These individuals may be at greater risk for becoming ill with the flu or may suffer more severe complications.

Who should not be vaccinated for flu

Some people should not be vaccinated without first consulting a physician.

These include:

People who have a severe allergy to chicken eggs
People who have had a severe reaction to an influenza vaccination
People who developed Guillain-Barré syndrome (GBS) within 6 weeks of getting an influenza vaccine
Children less than 6 months of age (influenza vaccine is not approved for this age group)
People who have a moderate-to-severe illness with a fever should wait until they recover to be vaccinated.