Immunization Against Influenza 2007-2008

Board Chair Approved: July 18, 2007

The American Academy of Family Physicians has adopted the following recommendations for immunizing persons against influenza which are consistent with those of the Advisory Committee on Immunization Practices to the Centers for Disease Control and Prevention (CDC) as reported in the June 29, 2007 Morbidity and Mortality Weekly Report (MMWR). The American Academy of Family Physicians recommends for the 2007-08 influenza season that all individuals in the categories listed below be immunized against influenza. Additionally, providers should offer influenza vaccine and immunization clinics throughout the influenza season. Recommendations for Using Inactivated and Live, Attenuated Influenza Vaccines Both the trivalent inactivated influenza vaccine (TIV) and the live attenuated influenza vaccine (LAIV) can be used to reduce the risk for influenza. LAIV is approved for use among non-pregnant healthy people aged 5—49 years. TIV is approved for persons aged ≥6 months, including those who are healthy and those with chronic medical conditions. (See following sections on TIV and LAIV).

All children aged 6 months to 8 years who have not been previously vaccinated at any time with either LAIV or TIV should receive 2 doses of vaccine. Those children aged 6 months to 8 years who receive TIV should have a booster dose of TIV administered ≥ 4 weeks after the initial dose, before the onset of influenza season, if possible. Those children aged 5 years to < 9 years who receive LAIV should have a second dose of LAIV ≥ 6 weeks after the initial dose, before the influenza season, if possible. If a child aged 6 months to 8 years received influenza vaccine for the first time during a previous season but did not receive a second dose of vaccine within the same season, it is recommended that two doses of vaccine be administered this season followed by single doses in subsequent years.

Target Groups for Vaccination

A. Persons at Risk for Medical Complications from influenza
Vaccination with TIV is recommended for the following persons who are at increased risk for severe complications from influenza, or at higher risk for influenza-associated clinic, emergency department, or hospital visits:

Children aged 6-59 months (i.e., 6 months-4 years);
Persons aged ≥ 50 years;
Women who will be pregnant during the influenza season;
Children and adolescents (aged 6 months-18 years) who are receiving long-term aspirin therapy and, therefore, might be at risk for experiencing Reye syndrome after influenza infections;
Adults and children who have chronic disorders of the pulmonary (including asthma), cardiovascular (except hypertension), renal hepatic, hematological or metabolic disorders (including diabetes mellitus):
Adults and children who have required regular medical follow-up or hospitalization during the preceding year because of chronic metabolic disease (including diabetes mellitus), renal dysfunction, hepatic or hematological disorders, or immunosuppression (including immunosuppression caused by medications or by human immunodeficiency virus);
Adults and children who have immunosuppression (including immunosuppression caused by medications or by HIV);
Adults and children who have any condition (e.g., cognitive dysfunction, spinal cord injuries, seizure disorders, or other neuromuscular disorders) that can compromise respiratory function or the handling of respiratory secretions, or that can increase the risk for aspiration; and
Residents of nursing homes and other chronic-care facilities that house persons of any age who have chronic medical conditions.

B. Persons Who Live With or Care for Persons at High Risk for Influenza-Related Complications

To prevent transmission to persons identified above, vaccination with TIV or LAIV (unless contraindicated) also is recommended for the following persons:
Health Care Professionals;
Healthy household contacts (including children) and caregivers of children aged ≤59 months (i.e., aged < 5 years) and adults ≥ 50 years; and
Healthy household contacts (including children) and caregivers of persons with medical conditions that put them at higher risk for severe complications from influenza.

C. Children

Any child aged ≥6 months may be vaccinated. However, vaccination is specifically recommended for certain children, including all children aged 6-59 months, children with certain medical conditions, and children who are contacts of persons at higher risk for influenza complications. Because children aged 6-23 months are at substantially increased risk for influenza-related hospitalizations, and children aged 24-59 months (i.e. 2-4 years) are at increased risk for influenza-related clinic and emergency department visits, ACIP recommends that all children aged 6 months – 4 years receive TIV. Influenza vaccines are not approved by the FDA for use among children aged <6 months.

All children aged 6 months – 8 years who have not received vaccination against influenza previously should receive 2 doses of vaccine the first year they are vaccinated. Children aged 5-8 years who receive TIV should have a booster dose of TIV administered ≥1 month after the initial dose, if possible before the onset of influenza season. LAIV is not currently licensed for children aged <5 years. Children aged 5-8 years who receive LAIV should have a second dose of LAIV 6 or more weeks after the initial dose. If possible, both doses should be administered before onset of the influenza season. However, vaccination, including the second dose, is recommended even after influenza virus begins to circulate in a community.

An algorithm for determining recommended influenza immunization actions for children can be accessed at: http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5606a1.htm?s_cid=rr5606a1_e

D. Any person who wishes to reduce the likelihood of becoming ill with influenza

Use of the Live, Attenuated Influenza Vaccine (LAIV)

Live, Attenuated Influenza Vaccine (LAIV) is an option for vaccination of healthy, non-pregnant persons aged 5-49 years who want to avoid influenza, and those who might be in close contact with persons at high risk for severe complications, including healthcare workers. During periods when inactivated vaccine is in short supply, use of LAIV is encouraged when feasible for eligible person (including health-care workers) because use of LAIV by these persons might increase availability of inactivated vaccine for persons in groups at high risk. Possible advantages of LAIV include its potential to induce a broad mucosal and systemic immune response, its ease of administration, and the acceptability of an intranasal rather than intramuscular route of administration.

The following populations should NOT be vaccinated with LAIV:

Persons aged <5 years or those ≥ 50 years;*
Persons with asthma, reactive airways disease or other chronic disorders of the pulmonary or cardiovascular systems; persons with other underlying medical conditions, including such metabolic diseases as diabetes, renal dysfunction, and hemoglobinopathies; or persons with known or suspected immunodeficiency diseases or immunosuppressed states;*
Children or adolescents receiving aspirin or other salicylates (because of the association of Reye syndrome with wild-type influenza infection);*
Persons with a history of GBS (Guillain-Barré Syndrome);
Pregnant women;* or
Persons with a history of hypersensitivity, including anaphylaxis, to any of the components of LAIV or to eggs.

*These persons should receive TIV.
Information regarding influenza surveillance, prevention, detection, and control is available at http://www.cdc.gov/flu/weekly/fluactivity.htm or by calling the CDC Immunization hotline at 800-232-2522 (English) or 800-232-0233 (Spanish).

Recommendations for Using Antiviral Agents for Influenza

Antiviral drugs for influenza are an adjunct to influenza vaccine for controlling and preventing influenza. However, these agents are not a substitute for vaccination. Four licensed influenza antiviral agents are available in the United States: amantadine, rimantadine, zanamivir, and oseltamivir.

Influenza A virus resistance to amantadine and rimantadine can emerge rapidly during treatment. ACIP recommends that neither amantadine nor rimantadine be used for the treatment or chemoprophylaxis of influenza A in the United States during the 2007-08 influenza season.

Oseltamivir or zanamivir can be prescribed if antiviral treatment of influenza is indicated. Osltamivir is approved for treatment of persons aged ≥ 1 year, and zanamivir is approved for treatment of persons aged ≥ 7 years. Oseltamivir and zanamivir can be used for chemoprophylaxis of influenza; oseltamivir is licensed for use in persons aged ≥ 1 year, and zanamivir is licensed for use in persons aged ≥ 5 years.

Detailed information regarding amantadine and rimantadine is available in the previous publication of the ACIP influenza recommendations. http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5606a1.htm?s_cid=rr5606a1_e

Influenza Vaccine Supply and Timing of Annual Influenza Vaccination

The annual supply of influenza vaccine and the timing of its distribution cannot be guaranteed in any year. Influenza vaccine distribution delays and vaccine shortages remain possible in part because of the inherent critical time constraints in manufacturing the vaccine given the annual updating of the influenza vaccine strains. To ensure optimal use of available doses of influenza vaccine, health-care clinicians, those planning organized campaigns, and state and local public health agencies should:

Develop plans for expanding outreach and infrastructure to vaccinate more persons than last year and;
Develop contingency plans for the timing and prioritization of administering influenza vaccine, if the supply is delayed and/or reduced.

These recommendations are provided only as assistance for physicians making clinical decisions regarding the care of their patients. As such, they cannot substitute for the individual judgment brought to each clinical situation by the patient's family physician. As with all reference resources, they reflect the best understanding of the science of medicine at the time of publication, but they should be used with the clear understanding that continued research may result in new knowledge and recommendations.