The Full-Court Press for Influenza Prevention in Elderly Persons

Influenza causes an average of 36,000 deaths and 114,000 hospitalizations annually in the Unites States [1]. Over 90% of these deaths and ∼50% of hospitalizations occur among persons ⩾65 years of age, with persons ⩾85 years of age having substantially higher rates of death than any other age group [2]. Nursing home residents are particularly vulnerable to high influenza illness rates and complications when influenza is introduced into a facility. During uncontrolled outbreaks of influenza in nursing homes, illness rates as high as 60% and mortality rates of >10% have been reported [3, 4]. Such outbreaks may be particularly severe when influenza type A (H3N2) viruses or viruses that have drifted from vaccine strains predominate. In the years when the study by Monto et al. [5] was conducted, influenza activity was mild, compared with other recent years. However, even in these milder influenza seasons, 8 (26%) of 31 homes in the second year of the study had documented circulation of influenza, despite vaccination rates of ⩾80% among residents. Although vaccination is an essential component of influenza prevention in the elderly population, it is by no means sufficient for the protection of nursing home populations. One of the major challenges for limiting severe health consequences of influenza is that elderly individuals, and particularly those in nursing homes, may also have suboptimal antibody response to influenza vaccination, the primary means of prevention. Information from studies on the effectiveness of the vaccine has, in general, shown diminished effectiveness in older persons, compared with younger healthy persons [1]. This less-robust protection from influenza in elderly persons after vaccination is likely due to immune senescence and/or the presence of chronic medical conditions and the increasingly common use of immunosuppressive medications [6, 7]. Although the effectiveness of the vaccine in preventing influenza respiratory illness in nursing home residents has been estimated to be 30%–40% when the vaccine and circulating virus strains are well matched, the vaccine can provide 47%–95% protection against influenza-related hospitalization and death [3]. Thus, the vaccine provides substantial benefit. In addition to providing protection to vaccinated individuals, vaccination of ⩾80% of nursing home residents in a facility has been shown to provide herd immunity protection and reduced risk of influenza outbreaks [3, 8]. However, despite the well-known benefits of influenza vaccination, only 57%–61% of nursing homes in this study vaccinated >80% of residents (the goal set by Healthy People 2000); the mean vaccination rates (76%–79%) were well below the Healthy People 2010 goal of 90% [5]. Vaccination of health care workers is another essential component of influenza prevention in nursing homes. In reports of influenza outbreaks in health care settings, unvaccinated health care workers are often implicated as the source of influenza introduction to and/or spread within facilities. Thus vaccination of nursing home staff and other health care workers is a long-standing recommendation [1]. The influenza vaccine is likely to be much more effective in health care workers than in the elderly, and, indeed, vaccination of health care workers has been associated with reductions in deaths among nursing home residents [9]. Despite the known benefits of influenza vaccination in preventing illness among patients and health care workers, the vaccination rates among health care workers are as dismal nationally (38%) [1] as they were among health care workers in these informed nursing homes studied by Monto et al. [5]. Because the vaccine is not 100% effective, vaccination rates among residents and health care workers are suboptimal, and the consequences of influenza infection in elderly persons are often severe: additional measures are needed to protect nursing home patients from influenza. The Centers for Disease Control and Prevention [1] and other organizations recommend a coordinated approach to influenza prevention and control in nursing homes that, in addition to influenza vaccination of staff and residents, includes (1) educating health care workers about the signs and symptoms of influenza in residents, (2) surveillance for respiratory illness among residents, (3) early testing for influenza when a cluster of respiratory illness is identified, (4) use of droplet precautions for persons with suspected influenza, (5) cohorting of persons with respiratory illness, (6) cancellation of group activities during respiratory illness outbreaks to minimize transmission, (7) limiting the “floating” of nursing staff between affected and unaffected wards to prevent spread of influenza by health care workers, (8) use of influenza antiviral medications for the prophylaxis and treatment of residents regardless of their vaccination status, (9) restricting ill staff from patient contact, and (10) continued monitoring for respiratory illness and antiviral medication side effects among residents during the course of the outbreak. When appropriately implemented, the combined use of rapid diagnosis, antiviral drugs, and other infection-control measures to reduce contact between ill and non-ill residents can rapidly halt the spread of influenza during nursing home outbreaks, as demonstrated by Monto et al. [5] and others [10], but the partial initiation of efforts is often not successful. For example, use of cohorting alone for influenza may not be sufficient to prevent the spread of influenza, probably because these efforts may not be strictly adhered to and because persons (i.e., patients and staff) without symptoms or with mild symptoms that may not increase suspicion for influenza may be shedding virus and spreading influenza to other persons. Approximately 50% of persons infected with influenza may have very mild or no symptoms of influenza, making it difficult to rely solely on isolation of symptomatic persons as an effective control measure [1]. As another example, administration of influenza antiviral medications only to residents on affected wards and not to those in the entire facility as recommended is often followed by further spread. In addition, because resistance to antiviral medication may develop in ∼30% of infected persons taking either rimantadine or amantadine for influenza type A and in 1.3%–8.6% of those taking oseltamivir for influenza types A or B, cohorting of ill persons receiving treatment is essential to prevent the spread of antiviral-resistant virus [1]. A full-court press to prevent, detect, and control influenza in nursing homes, however, requires preplanning and coordination. How many nursing homes are able to accomplish such feats in addition to their many other demands? In the study by Monto et al. [5], even after nursing home staff had been educated about influenza prevention recommendations, only 1 of the 8 nursing homes with confirmed influenza both rapidly recognized the outbreak and administered antiviral prophylaxis to all residents. A survey of nursing homes in 9 states, which was conducted in 1998, also found low rates of compliance with the recommendations [11]. In this survey, 99% of nursing homes offered influenza vaccine to residents, but only 86% offered influenza vaccine to their staff. Two-thirds of homes had access to rapid influenza testing, and only 19% had a written policy for using antiviral medications in the event of an influenza outbreak. Of those states included in the survey, nursing homes from New York reported higher vaccination rates of residents and were more likely to report that they offered influenza vaccine to staff. In addition, a higher proportion of these nursing homes had a policy for the use of antiviral medications, had access to rapid influenza testing, and reported high rates of influenza outbreaks among patients. One of the reasons for the differences in use of influenza prevention and control measures was hypothesized to be the involvement of the health department and infection-control professional groups in educational programs at New York nursing homes over many years about influenza and outbreak recognition and response. In support of this hypothesis, New York homes were also more likely to report suspected influenza outbreaks to the health department when they occurred. But even in these New York homes or those enrolled in the Monto et al. [5] study, noncompliance with recommended influenza-prevention strategies was substantial. What can be done to improve the implementation of current influenza prevention and control recommendations in nursing homes? First, yearly, sustained efforts by public health officials in partnership with other medical professional organizations, such as quality improvement organizations, to improve awareness of influenza prevention, detection, and control recommendations and their implementation is likely to be of benefit, on the basis of the New York experience. In addition, implementation of standing orders programs can substantially improve vaccination coverage and help operationalize vaccination programs in nursing homes [12]. Furthermore, some state legislatures have enacted legal remedies to improve vaccination of both residents and staff, and influenza vaccination of residents has been proposed as a quality performance measure by the National Quality Forum. It has now been >10 years since Medicare began to cover the cost of influenza vaccination for the elderly population, and substantial progress has been made in improving vaccination rates among persons aged ⩾65 years. Now the challenge is in completing the task of optimizing protection of nursing home residents from a preventable disease with high mortality. Conflict of interest. C.B.B. and S.H.: No conflict.