The Centers for Disease Control and Prevention, the Healthcare Infection Control Practices Advisory Committee (HICPAC), and the Advisory Committee on Immunization Practices (ACIP) have released recommendations on the influenza vaccination of health care professionals. The full report was published in the February 24, 2006, issue of Morbidity and Mortality Weekly Report and is available athttp://www.cdc.gov/mmwr/preview/mmwrhtml/rr5502a1.htm.

Influenza transmission between health care professionals and patients is well documented. Influenza vaccination has positive effects on patient outcomes, work absences, and infection rates. By attaining and sustaining higher rates of influenza vaccination, health care professionals and patients will be better protected, and disease burden and health care costs will be reduced.

Background

There is limited evidence regarding the incidence of influenza in health care settings. In a randomized trial, 13 percent of health care professionals who were given placebo instead of vaccination were infected with influenza. In a cross-sectional survey, 37 percent of health care professionals reported one influenza-like illness in eight months, and nine percent reported more than one such illness. Length of illness (range = one to 10 days) and the number of days absent from work (range = zero to 10 days) varied.

Evidence shows that approximately 70 to 90 percent of healthy persons younger than 65 years do not get ill when vaccinated with trivalent inactivated influenza vaccine. Vaccination of healthy adults also decreases the number of work days missed and reduces the use of health care resources. Similar benefits have been found when live, attenuated influenza vaccine (LAIV) is given to healthy working adults 18 to 64 years of age. One study showed that vaccination with LAIV reduced prescription antibiotic use, work absences, physician visits, and rates of severe febrile and upper respiratory tract illnesses. Vaccination of health care professionals also has been shown to reduce transmission of influenza in health care environments, staff illness and work days missed, and influenza-related morbidity and mortality in persons at increased risk of severe influenza.

Transmission

Outbreaks of influenza in hospitals and long-term care facilities have been associated with low vaccination rates in staff. One study on the relationship between vaccination of health care professionals and annual incidence of nosocomial influenza from 1987 to 2000 showed that there was a significant and inverse relationship between vaccination rates and illness rates among patients. These results suggest that staff vaccination was a factor in the decline in influenza rates.

STAFF ILLNESS

Two randomized, placebo-controlled, double-blind trials studied the impact of influenza vaccination on staff sickness and number of work days missed. One trial showed that vaccinated health care professionals had 28 percent fewer work absences from respiratory infection compared with unvaccinated staff (1.0 and 1.4 days, respectively; P = .02). The other trial showed that vaccinated staff also had a lower incidence of influenza compared with the control group (1.7 percent compared with 13.4 percent), had fewer total respiratory illnesses (28.7 per 100 persons compared with 40.6 per 100 persons, P = .57), and missed fewer days of work (9.9 per 100 persons compared with 21.1 per 100 persons, P = .41). A cross-sectional survey showed that overall, vaccinated staff had 23 percent fewer influenza-like illnesses and 27 percent fewer days of illness compared with their unvaccinated coworkers.

PATIENT OUTCOMES

Decreasing transmission of influenza from health care professionals to patients at high risk for influenza complications could reduce influenza-related deaths. Long-term care residents are especially susceptible to influenza, and during outbreaks as many as 25 to 60 percent of residents will contract influenza; 10 to 20 percent of those infections will be fatal. In a randomized controlled trial (RCT) studying the impact of influenza vaccination in health care professionals on the outcomes of nursing home residents, staff vaccination resulted in a 43 percent decrease in the incidence of influenza-like illness (odds ratio [OR] = 0.6; 95% confidence interval [CI], 0.3 to 0.9) and a 44 percent decrease in overall mortality rates. Another RCT showed that compared with control facilities, crude mortality rates were 42 percent lower in residents who lived in facilities with higher staff vaccination rates (OR = 0.6; 95% CI, 0.4 to 0.8; P = .014).

COST EFFECTIVENESS

In adults younger than 65 years, vaccination can reduce direct costs (e.g., medical) and indirect costs (e.g., work absenteeism). Studies have shown a 13 to 44 percent reduction in health care visits, an 18 to 45 percent reduction in work absences, an 18 to 28 percent reduction in reduced productivity, and a 25 percent reduction in antibiotic use for influenza-like illness in vaccinated persons. In persons 18 to 64 years of age, vaccination has been shown to save approximately $60 to $4,000 per illness, depending on effectiveness, cost, and infection rates.

BARRIERS

Barriers to influenza vaccination in health care professionals include fear of side effects and needles, not having enough time or being inconvenienced, medical contraindication, perceived vaccine ineffectiveness, reliance on homeopathic medications for treatment, and avoidance of medication.

Side Effects and Adverse Reactions

When providing education about potential side effects of vaccination, physicians should emphasize that inactivated influenza vaccine contains noninfectious killed virus and cannot cause influenza, but that unrelated and coincidental respiratory disease can occur. Soreness at the vaccination site, the most commonly reported reaction, affects 10 to 64 percent of patients. After administration of inactivated vaccine, fever, malaise, myalgia, and other systemic symptoms can occur, usually in persons with no previous exposure to influenza virus antigens. Presumed allergic reactions such as hives and angioedema rarely occur; these types of reactions typically are the result of hypersensitivity to vaccine components (e.g., residual egg protein).

Since the 1976 swine influenza vaccine, there has been no substantial increase in rates of Guillain-Barré syndrome associated with influenza vaccination. If the current vaccine poses a risk, it is only an estimated one additional case per 1 million persons vaccinated. Whether vaccination increases the risk of recurrence of this syndrome is unknown.

The most commonly reported side effects of LAIV in adults are nasal congestion, runny nose, headache, and sore throat. Reactions such as pneumonia, bronchitis, and central nervous system events have not occurred more often in LAIV recipients compared with a placebo group. Less than one percent of healthy adults 18 to 49 years of age who received LAIV have serious adverse effects.

General Influenza Vaccination Recommendations

The ACIP and HICPAC approved the following recommendations regarding influenza vaccination of health care professionals:

• Health care professionals should be educated on the benefits of vaccination and possible consequences of the illness on themselves and their patients. They also should be educated on the epidemiology, transmission, diagnosis, treatment, and nonvaccine infection control strategies in accordance with their level of responsibility in preventing health care–associated influenza.

• Influenza vaccine should be offered annually to health care professionals to help decrease work absences and protect staff, patients, and family members. When inactivated vaccine is in short supply, and when feasible, the use of LAIV is encouraged.

• As a component of employee health programs, vaccination should be provided at no cost. One survey showed that 33 percent of health care professionals said they would not get vaccinated if they had to pay for it. Strategies that have been shown to increase vaccination acceptance also should be implemented (e.g., clinics, mobile carts, modeling and support by managers).

• For persons who decline vaccination for reasons other than medical contraindications, a signed declination should be obtained.

• Rates of vaccination coverage and declination specific to ward, unit, and specialty should be monitored so that feedback can be provided to the staff.

• Level of vaccination coverage should be a measure included in the patient safety quality program.

Strategies for Improving Vaccination Rates

EDUCATION

Educational programs that highlight the benefits of influenza vaccination for staff and patients can help improve vaccination rates. Rates can also be increased by promotional campaigns or efforts to make vaccination more accessible.

ROLE MODELS

Health care professionals have been shown to be more accepting of vaccination if their managers are vaccinated.

ACCESS

Acceptance of vaccination can be increased if administrative barriers (e.g., costs) are removed and if vaccine location and times are easily accessible. A three-year prospective study found that vaccination rates increased four-to fivefold when mobile carts were used for vaccinations.

MEASUREMENT

Influenza vaccination coverage should be monitored. When coverage is less successful in certain areas, interventions can be made. Collecting declination forms can help identify groups to which interventions should be directed.

LEGISLATION

Legislation has had a positive effect on hepatitis B vaccination rates among health care professionals. Thirteen states and the District of Columbia enacted regulations in 2005 regarding the influenza vaccination of staff at long-term care facilities. However, current data are insufficient to determine the effect of these efforts.

Inactivated Influenza Vaccine and LAIV Use Recommendations

INACTIVATED INFLUENZA VACCINE

Inactivated vaccine has been approved for all persons older than six months who do not have contraindications. Persons who have anaphylactic hypersensitivity to eggs or other vaccine components should consult a physician before being vaccinated, and persons with acute febrile illness should not be vaccinated until their symptoms have subsided. Because of declining immunity after one year, health care professionals should be given one vaccine dose per year. Intramuscular injection into the deltoid muscle using a needle longer than one inch is recommended. Inactivated influenza vaccine is the preferred vaccine for health care professionals who work closely with severely immunosuppressed persons.

LAIV

LAIV is approved for use only in nonpregnant healthy persons five to 49 years of age. It should not be used in health care professionals who have immunocompromised patients. Other persons who should not receive LAIV include those with asthma, reactive airway disease, or other chronic disorders of the pulmonary or cardiovascular systems; those with underlying medical conditions such as diabetes, renal dysfunction, or hemoglobin-opathies; those with immunodeficiency diseases or those receiving immunosuppressive therapies; and those with a history of Guillain-Barré syndrome or hypersensitivity. Children taking aspirin or other salicylates should not be given LAIV.

Eligible persons should be given one dose intranasally while sitting upright. Approximately 0.25 mL is sprayed into the first nostril, and another 0.25 mL into the second nostril. The dose should not be repeated if the recipient sneezes. If the recipient has nasal congestion, administration should be done at a later date when symptoms have cleared and the spray can be easily delivered to the nasopharyngeal mucosa. Inactivated vaccine can be used simultaneously with or any time before or after LAIV administration.

TIMING

The best time to administer the vaccination is during October and November. Although influenza seasons vary across the country, November is the most beneficial vaccination time in most areas. To improve coverage, vaccination should continue to be offered throughout influenza season as long as supplies last. Antibody protection peaks in adults two weeks after vaccination.