On June 29, 2007 the Advisory Committee on Immunization Practices (ACIP) of the Centers for Disease Control and Prevention (CDC) released updated recommendations on the prevention and control of influenza. Some principal updates and changes include:
- Highlighting the previous recommendation that all persons who want to reduce the risk of becoming ill with influenza or transmitting it to others should be vaccinated;
- Emphasizing that immunization providers should offer the vaccine and schedule immunization clinics throughout the influenza season;
- Recommending that healthcare facilities consider the level of vaccination coverage among health care professionals (HCP) to be a measure of a patient safety quality program and implement policies to encourage HCP vaccination (e.g., obtaining signed statements from HCP who decline influenza vaccination); and
- Using the 2007-2008 vaccine virus strains A/Solomon Islands/3/2006 (H1N1)-like (new for this season), A/Wisconsin/67/2005 (H3N2)-like, and B/Malaysia/2506/2004-like antigens.
Types of Vaccine
The two types of vaccine reviewed in the guidelines are trivalent inactivated influenza vaccine (TIV) and live, attenuated influenza vaccine (LAIV). As was stated in the 2006 document, TIV may be used for any person aged 6 months or older, including those with high-risk conditions. LAIV currently is approved only for use among healthy, non-pregnant persons aged 5–49 years. Therefore, most nursing and assisted living facility residents would be immunized with TIV, whereas individuals in community based settings (e.g., group homes) who may be younger could receive LAIV if appropriate. Although not specifically mentioned in the guidelines, residents of intermediate care facilities (for mental retardation, etc.) should also be evaluated for immunization. Because influenza viruses undergo frequent changes, it is necessary to be vaccinated annually against the influenza viruses currently in circulation.
Antiviral medications are an adjunct to vaccination and are effective when administered as treatment and when used for chemoprophylaxis after an exposure to influenza virus. Oseltamivir and zanamivir are the only antiviral medications currently recommended for use in the United States; resistance to oseltamivir or zanamivir remains rare. Amantadine or rimantidine should not be used for the treatment or prevention of influenza in the United States until evidence of susceptibility to these antiviral medications has been reestablished among circulating influenza A viruses. Table 6 of the guidelines provides more information about the administration of antiviral medications.
Influenza Vaccine Supply Considerations
The annual supply of influenza vaccine and the timing of its distribution cannot be guaranteed in any year. During the 2006–07 influenza season, over 100 million doses of influenza vaccine were distributed in the United States; similar rates are expected for the 2007–08 season, depending on demand and production yields. If TIV supply is limited, priority is typically assigned to high risk individuals including all persons 50 years or older, residents of nursing homes and other chronic care facilities, and health care personnel aged 50 years or older. Specific guidance for tiered use of TIV during prolonged distribution delays or supply shortfalls is available at http://www.cdc.gov/flu/professionals/vaccination/vax_priority.htm.
As previously mentioned, TIV can be used for all persons 6 months of age and older, while LAIV is only appropriate for non-pregnant people and/or those between 5 and 49 years old. Therefore, shortage of TIV is especially problematic. Therefore, during shortages of TIV, LAIV should be used preferentially when feasible for all appropriate persons (including HCP) who desire or are recommended for vaccination to increase the availability of TIV for persons at high risk.
Timing of Vaccination
Vaccination efforts should be structured to promote the vaccination of as many persons as possible before influenza activity begins in the community. In general, health care providers should begin offering vaccination soon after vaccine becomes available, if possible, by October. The majority of adults have antibody protection against influenza virus infection within 2 weeks after vaccination.
Vaccination programs should be scheduled through December, and later if feasible, with attention to settings that serve high risk groups, including persons in long term care facilities, persons aged <50 years at increased risk for influenza-related complications, persons aged >50 years, and HCP. During a vaccine shortage or delay, substantial proportions of TIV doses may not be released and distributed until November and December, or later. When the vaccine is substantially delayed or disease activity has not subsided, organizations should consider offering vaccination into January and beyond as long as vaccine supplies are available. Campaigns using LAIV also may extend into January and beyond. Residents admitted after completion of the vaccination program at the facility should be vaccinated at the time of admission through March.
Strategies for Implementing Vaccination Recommendations in Health Care Settings
Successful vaccination programs combine publicity and education for potential vaccine recipients, including HCP and patients; a plan for identifying persons recommended for vaccination; use of reminder/recall systems; assessment of practice-level vaccination rates with feedback to staff; and efforts to remove administrative and financial barriers that prevent persons from receiving the vaccine, including use of standing orders programs.
Since October 2005, the Centers for Medicare and Medicaid Services (CMS) has required nursing homes participating in the Medicare and Medicaid programs to offer all residents influenza and pneumococcal vaccines and to document the results (for more information, see documents under the bullet entitled "New F tag 334 and Survey Guidance on Influenza and Pneumococcal Vaccination." According to these requirements, each resident is to be vaccinated unless contraindicated medically, the resident or a legal representative refuses vaccination, or the vaccine is not available because of shortage. This information is to be reported as part of the CMS Minimum Data Set, which tracks nursing home health parameters.
The use of standing orders programs by long term care facilities (e.g., nursing homes and skilled nursing facilities), hospitals, and home health agencies ensures that vaccination is offered. Standing orders programs for both influenza vaccinations should be conducted under the supervision of a licensed practitioner according to a physician-approved facility or agency policy by HCP trained to screen patients for contraindications to vaccination, administer vaccine, and monitor for adverse events. CMS has removed the physician signature requirement for the administration of influenza and pneumococcal vaccines to Medicare and Medicaid patients in hospitals, long-term–care facilities, and home health agencies. Payment for influenza vaccine under Medicare Part B is available. Other settings (e.g., outpatient and assisted living facilities,) are encouraged to introduce standing orders programs as well. In addition, physician reminders (e.g., flagging charts) and patient reminders are recognized strategies for increasing rates of influenza vaccination.
Health Care Personnel
Health care facilities should offer influenza vaccinations to all HCP, including night, weekend, temporary staff and students with patient contact. Particular emphasis should be placed on providing vaccinations to workers who provide direct care for persons at high risk for influenza complications. Efforts should be made to educate HCP regarding the benefits of vaccination and the potential health consequences of influenza illness for their patients, themselves, and their family members (see http://www.cdc.gov/vaccines/pubs/vis/default.htm#flu for Vaccine Information Statements). All HCP should be provided convenient access to influenza vaccine at the work site, free of charge, as part of employee health programs.
As previously stated, healthcare administrators should consider the level of vaccination coverage among HCP to be one measure of a patient safety quality program and should obtain signed declinations from personnel who decline influenza vaccination for reasons other than medical contraindications. Influenza vaccination rates among HCP within facilities should be regularly measured and reported, and it may be useful to evaluate ward-, unit-, and specialty-specific immunization rates of staff.
Sources of Information Regarding Influenza and Its Surveillance
Information regarding influenza surveillance, prevention, detection, and control is available at http://www.cdc.gov/flu. During October–May, surveillance information is updated weekly. In addition, periodic updates regarding influenza are published in the MMWR Weekly Report at http://www.cdc.gov/mmwr and information can also be obtained by calling 1-800-CDCINFO (1-800-232-4636). State and local health departments should be consulted concerning availability of influenza vaccine, access to vaccination programs, information related to state or local influenza activity, and advice concerning outbreak control.
Responding to Adverse Events After Vaccination
HCPs should report all clinically significant adverse events after influenza vaccination promptly to the Vaccine Adverse Event Reporting System (VAERS), even if the HCP is not certain that the vaccine caused the event. Clinically significant adverse events that follow vaccination should be reported at http://www.vaers.hhs.gov. Reports may be filed securely online or by telephone at 1-800-822-7967 to request reporting forms or other assistance.
Pandemic Avian Influenza
To date, highly pathogenic H5N1 influenza viruses have not been identified in wild or domestic birds or in humans in the United States. Current seasonal influenza vaccines provide no protection against human infection with avian influenza viruses, including H5N1. However, reducing seasonal influenza risk through influenza vaccination of persons who might be exposed to nonhuman influenza viruses (e.g., H5N1 viruses) might reduce the theoretical risk for recombination of an avian influenza virus and a human influenza virus by preventing seasonal influenza virus infection within a human host. The Occupational Safety and Health Administration (OSHA) also has recommended that HCP involved in the care of patients with documented or suspected avian influenza should be vaccinated with the most recent seasonal human influenza vaccine to reduce the risk for co-infection with human influenza viruses. Human infection with novel influenza virus strains, including influenza viruses that cause avian influenza, is now a nationally notifiable disease.
The influenza recommendations can be viewed in their entirety at http://www.cdc.gov/mmwr/pdf/rr/rr56e629.pdf.