HIV (human immunodeficiency virus) is the virus that causes AIDS (Acquired Immune Deficiency Syndrome). HIV kills or damages cells in the body's immune system, gradually destroying the body's ability to fight infection and certain cancers. An estimated 850,000 to 950,000 people are infected with HIV in the United States.

People with HIV/AIDS are considered at increased risk from serious influenza-related complications. Studies have shown an increased risk for heart- and lung-related hospitalizations in people infected with HIV during influenza season as opposed to other times of the year, and a higher risk of influenza-related death in HIV-infected people. Other studies have indicated that influenza symptoms might be prolonged and the risk of influenza-related complications higher for certain HIV-infected people. Vaccination with a flu shot has been shown to produce an immune response against influenza viruses in certain people infected with HIV.

Because influenza can result in serious illness, HIV-infected persons are recommended for vaccination. During the setting of the current vaccine shortage, people with HIV/AIDS are among the priority groups that should get flu shots this season.

This fact sheet provides Questions & Answers to guide both the administration of flu shots and antiviral medications in people with HIV/AIDS.

Should people with HIV/AIDS receive the inactivated influenza vaccine?

People with chronic underlying medical conditions, including HIV/AIDS, should receive inactivated influenza vaccine (the flu shot) during the 2004-05 influenza season. People with HIV/AIDS are considered at increased risk from serious influenza-related complications and should be vaccinated. Persons with advanced HIV disease may have a poor response to immunization. Therefore, chemoprophylaxis (use of antiviral medications for prevention) should be considered for these patients if they are likely to be exposed to people with influenza. (CDC has developed interim recommendations on the use of antiviral medications for the 2004-05 influenza season. These can be found at www.cdc.gov/flu/professionals/treatment/0405antiviralguide.htm.)

Are there people with HIV/AIDS who should NOT receive the inactivated influenza vaccine?

Contraindications to the use of inactivated influenza vaccine (the flu shot) in persons with HIV/AIDS are the same as those for uninfected persons ? a history of severe allergy (i.e., anaphylactic allergic reaction) to hens' eggs, or a history of onset of Guillain-Barre syndrome during the 6 weeks after vaccination.

Can people with HIV/AIDS receive the live attenuated flu vaccine (LAIV, sold commercially as FluMist)?

No. Persons with HIV/AIDS and persons with other medical conditions are not recommended to receive the live influenza vaccine. LAIV contains a weakened form of the live influenza virus. LAIV is approved for use only among healthy persons between the ages of 5 and 49 years.

When should people with HIV/AIDS be prescribed antiviral medications for chemoprophylaxis (prevention)?

Persons at high risk of serious influenza-related complications should be given antiviral medications if they are likely to be exposed to other people with influenza. For example, when a family or household member is diagnosed with influenza, the exposed person with HIV/AIDS should be given chemoprophylaxis for 7 days. Vaccinated and unvaccinated HIV-infected persons who are residents of institutions experiencing an influenza outbreak should be given chemoprophylaxis for the duration of the outbreak or until discharge. People with advanced HIV disease who are not expected to mount an adequate antibody response to influenza vaccination should consider chemoprophylaxis with antiviral medications for the duration of influenza activity in the community, if antiviral medications are available in adequate supply locally. (CDC has developed interim recommendations on the use of antiviral medications for the 2004-05 influenza season. These can be found at www.cdc.gov/flu/professionals/treatment/0405antiviralguide.htm.)

There are no published data on interactions between anti-influenza agents such as amantidine and rimantidine and drugs used in the management of HIV infected persons. Patients should be observed for adverse drug reactions to anti-influenza chemoprophylaxis agents, especially when neurologic conditions or renal insufficiency is present.

Should health-care workers who have contact with HIV/AIDS patients be vaccinated?

Influenza vaccination is recommended for health-care workers who are involved in direct care of HIV- infected patients. More information about vaccination of health-care workers can be found in "Prevention and Control of Influenza Recommendations of the Advisory Committee on Immunization Practices (ACIP)" at www.cdc.gov/mmwr/preview/mmwrhtml/rr5306a1.htm. Health-care workers who are healthy, less than 50 years of age, and are not pregnant may receive the nasal-spray flu vaccine (LAIV/FluMist).

For more information, visit www.cdc.gov/flu or call CDC at (800) CDC-INFO (English), (888) 246-2857 (Español), or (866) 874-2646 (TTY).