Influenza is a debilitating viral infection which can be fatal in high risk populations. Vaccination can prevent or reduce the severity of the infection.



(1) in the United States the influenza peak is between late December and early March

(2) in the tropics transmission is year round

(3) in the Southern hemisphere activity is from April through September


Potentially serious complications:

(1) severe primary influenza pneumonia

(2) secondary bacterial pneumonia

(3) exacerbation of underlying disease



(1) prepared from inactivated virus grown in eggs

(2) formulations include whole virus, split virus and purified surface antigen

(3) usually contains 3 viral strains, with two type A and one type B



(1) children < 9 years receiving the vaccine for the first time should receive 2 doses at least 1 month apart

(2) a dose of 0.5 mL is given IM to children 3 years or older and to adults

(3) a dose of 0.25 mL is given IM to children from 6 to 35 months of age

(4) The optimum time for vaccination in the United States is from October through mid-November, but may be given from September to the end of the flu season.


Recommended vaccine recipients: Groups at increased risk for influenza-related complications:

(1) persons >= 65 years of age or from 6 months to 19 years of age

(2) residents of chronic care facilities with chronic medical conditions

(3) adults and children with chronic pulmonary disorders, including asthma

(4) adults and children with chronic cardiovascular disorders

(5) adults and children with chronic metabolic diseases, including diabetes mellitus

(6) adults or children who are immunosuppressed

(7) adults or children with sickle cell disease or other hemoglobinopathies

(8) adults or children with chronic renal dysfunction

(9) adults or children with chronic hepatic disease

(10) children and adolescents ages 6 months to 18 years taking long-term aspirin, due to risk of Reye's syndrome after influenza

(11) women who will be in the second or third trimester of pregnancy during the influenza season

(12) many persons with HIV infection

(13) adults or children with a neuromuscular disorder associated with a risk of aspiration and/or inability to manage respiratory secretions


Recommended vaccine recipients - Groups that can transmit influenza to persons at high risk for influenza-related complications:

(1) physicians, nurses and other health care providers

(2) employees of nursing homes and chronic care facilities

(3) providers of home care to persons at high risk

(4) household members, including children, of persons in high risk groups

(5) caregivers of children less than 5 years old


Recommended vaccine recipients - Other groups:

(1) overseas travelers to regions having influenza activity

(2) persons who provide essential community services (police, fire fighters, others)

(3) students or other persons in institutional settings

(4) any person who wishes to reduce the likelihood of becoming ill with influenza



(1) persons with anaphylactic hypersensitivity to eggs or other components of the influenza vaccine

(2) persons with acute febrile illness should not be vaccinated until symptoms have abated

(3) an infant less than 6 months of age

(4) someone with a history of Guillain-Barre syndrome within 6 weeks of receiving the influenza vaccine

(5) someone who has had a severe reaction to the influenza vaccine


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