Am Fam Physician. 2008;78(8):996-999
Guideline source: Centers for Disease Control and Prevention, Advisory Committee on Immunization Practices
Literature search described? No
Evidence rating system used? No
Published source:MMWR Recommendations and Reports, August 8, 2008
Available at:http://cdc.gov/mmwr/preview/mmwrhtml/rr5707a1.htm
In the United States, annual epidemics of influenza occur typically during the late fall through early spring. Rates of infection are highest among children, and rates of serious illness and death are highest among persons 65 years and older, children younger than two years, and persons with medical conditions that put them at increased risk of complications from influenza. The Advisory Committee on Immunization Practices of the Centers for Disease Control and Prevention (CDC) has released updated recommendations for influenza control for the 2008–09 season.
Recommendations
The primary updates to this year's recommendations include the following:
Beginning this year, all children five to 18 years of age should be vaccinated annually. Vaccination should begin as soon as vaccine is available for the 2008–09 influenza season, but no later than during the 2009–10 season.
Annual vaccination of all children six months to four years of age should remain a focus of vaccination efforts because this group is at higher risk of complications.
Either trivalent inactivated influenza vaccine (TIV) or live, attenuated influenza vaccine (LAIV) should be used when vaccinating healthy persons two to 49 years of age (the previous recommendation was to administer LAIV to persons five to 49 years of age). Tables 1 and 2 list the available vaccines for the 2008–09 season and compare LAIV and TIV.
Vaccines containing the trivalent vaccine virus strains A/Brisbane/59/2007 (H1N1)-like, A/Brisbane/10/2007 (H3N2)-like, and B/Florida/4/2006-like antigens should be used during the 2008–09 influenza season.
Healthy, nonpregnant persons two to 49 years of age can choose to receive TIV or LAIV. Some TIV formulations are licensed for use in children as young as six months; TIV also is licensed for use in persons with high-risk conditions. LAIV is licensed for use only in persons two to 49 years of age, and the safety of LAIV has not been established in persons with certain medical conditions. All children six months to eight years of age who have not previously been vaccinated with at least one dose of LAIV or TIV should receive two doses of vaccine in the same season, with a single dose during subsequent seasons.
Influenza vaccine should be provided to all persons who want to reduce their risk of infection or of transmitting influenza to others. However, an emphasis should be placed on vaccinating patients at higher risk of influenza infection or complications, including children six months to 18 years of age, persons 50 years and older, and other adults at risk of medical complications from influenza or more likely to require medical care (Table 3). Persons who live with or care for persons at high risk of influenza-related complications, including health care professionals and caregivers for children younger than six months, should receive influenza vaccine annually.
Antiviral Agents
Four influenza antiviral agents are licensed in the United States: amantadine (Symmetrel), rimantadine (Flumadine), zanamivir (Relenza), and oseltamivir (Tamiflu). Oseltamivir-resistant influenza A (H1N1) strains have been identified in the United States and some other countries. However, oseltamivir and zanamivir continue to be the recommended agents for treatment of influenza because other virus strains remain sensitive to zanamivir, and resistance levels to other antiviral agents remain high.
Oseltamivir is licensed for treatment and chemoprophylaxis of influenza in persons one year and older, and zanamivir is licensed for treatment of influenza in persons seven years and older and for chemoprophylaxis in persons five years and older (for complete dosing information, see the CDC recommendations at http://cdc.gov/mmwr/preview/mmwrhtml/rr5707a1.htm). Antiviral treatment should be initiated within two days of illness onset; benefits are greater if treatment is started earlier. Although chemoprophylaxis is not a substitute for vaccination, it is a critical adjunct in preventing and controlling influenza. To be maximally effective as chemoprophylaxis, the drug must be taken each day for the duration of influenza activity in the community.
| Vaccine | Brand name | Manufacturer | Presentation | Mercury content (mcg Hg per 0.5-mL dose) | Approved ages | Number of doses required | Route of administration |
|---|---|---|---|---|---|---|---|
| TIV* | Fluzone | Sanofi Pasteur | 0.25-mL prefilled syringe | 0 | 6 to 35 months | 1 or 2† | IM‡ |
| 0.5-mL prefilled syringe | 0 | ≥ 36 months | 1 or 2† | IM‡ | |||
| 0.5-mL vial | 0 | ≥ 36 months | 1 or 2† | IM‡ | |||
| 5.0-mL multidose vial | 25 | ≥ 6 months | 1 or 2† | IM‡ | |||
| TIV* | Fluvirin | Novartis Vaccines | 5.0-mL multidose vial | 24.5 | ≥ 4 years | 1 or 2† | IM‡ |
| 0.5-mL prefilled syringe | < 1.0 | ≥ 4 years | 1 or 2† | IM‡ | |||
| TIV* | Fluarix | GlaxoSmithKline | 0.5-mL prefilled syringe | < 1.0 | ≥ 18 years | 1 | IM‡ |
| TIV* | Flulaval | GlaxoSmithKline | 5.0-mL multidose vial | 25 | ≥ 18 years | 1 | IM‡ |
| TIV* | Afluria | CSL Biotherapies | 0.5-mL prefilled syringe | 0 | ≥ 18 years | 1 | IM‡ |
| 5.0-mL multidose vial | 25 | ≥ 18 years | 1 | IM‡ | |||
| LAIV§ | Flumist‖ | Medimmune | 0.2-mL sprayer | 0 | 2 to 49 years | 1 or 2¶ | Intranasal |
| Factor | LAIV | TIV |
|---|---|---|
| Route of administration | Intranasal spray | Intramuscular injection |
| Number of included virus strains | 3 (2 influenza A, 1 influenza B) | 3 (2 influenza A, 1 influenza B) |
| Frequency of updates to vaccine virus strains | Annually | Annually |
| Frequency of administration | Annually* | Annually* |
| Approved ages | 2 to 49 years † | 6 months and older |
| Interval between doses for children 6 months to 8 years of age who are receiving vaccine for the first time | 4 weeks | 4 weeks |
| Can be administered to persons at risk of influenza-related complications† | No | Yes |
| Can be administered to children with asthma or children 2 to 4 years of age with a history of wheezing during the preceding year‡ | No | Yes |
| Can be administered to close contacts of immunosuppressed persons who do not require a protective environment | Yes | Yes |
| Can be administered to close contacts of immunosuppressed persons who require a protective environment (e.g., hematopoietic stem cell transplant recipients) | No | Yes |
| Can be administered to close contacts of persons at high risk, but who are not severely immunosuppressed | Yes | Yes |
| Can be simultaneously administered with other vaccines | Yes§ | Yes‖ |
| If not simultaneously administered, can be administered within 4 weeks of another live vaccine | Prudent to space 4 weeks apart | Yes |
| If not simultaneously administered, can be administered within 4 weeks of an inactivated vaccine | Yes | Yes |
Data are limited about the effectiveness of zanamivir and oseltamivir in preventing serious influenza-related complications (e.g., bacterial or viral pneumonia, exacerbation of chronic disease), or for preventing influenza in persons at high risk of serious complications from the disease.
| Children and adolescents |
| Children six months to four years of age |
| Children who are receiving long-term aspirin therapy (increases the risk of Reye syndrome after influenza infection) |
| Adults |
| Adults 50 years and older |
| Health care professionals |
| Any age |
| Household contacts and caregivers for persons with medical conditions that put them at higher risk of complications from influenza |
| Household contacts and caregivers for children younger than five years (especially for those younger than six months), and for adults 50 years and older |
| Persons with any condition that may compromise respiratory function or increase the risk of aspiration (e.g., cognitive dysfunction, spinal cord injuries, seizure disorders) |
| Persons with chronic pulmonary disorders (including asthma), or renal, hepatic, hematologic, or metabolic disorders (including diabetes mellitus) |
| Persons with immunosuppression (including immunosuppression caused by medications or human immunodeficiency virus) |
| Residents of nursing homes or chronic-care Facilities |
| Persons who are pregnant during influenza season |