Influenza Outbreaks in Long-Term Care Practical Approaches to Prevention and Control © Alloy Photography/Veer
Dear Colleague: Influenza remains the leading infectious cause of death from a virus for older adults in the United States. Many long-term care facilities experience outbreaks of respiratory illness but fail to recognize influenza as a source of additional hospitalizations, exacerbations of heart failure or emphysema, or heart attacks and strokes because the laboratory tests to prove they’re secondary to influenza typically aren’t ordered. In 2012, for example, outbreaks of influenza were occurring as late as May and early June, but would have been overlooked if such testing had not been done. Influenza vaccine can reduce the severity of outbreaks. The combined reduction in heart attacks and strokes realized by those vaccinated may be even greater than the reduced incidence of pneumonia. Getting nursing home residents vaccinated has become easier as long-term care facility policies have included influenza vaccination as part of the current standard of care. Continued on page 2
Faculty Reviewer Stefan Gravenstein, MD, MPH Professor of Medicine and Health Services Policy and Practice Alpert Medical School of Brown University Clinical Director, Healthcentric Advisors Providence, Rhode Island
A
ccording to the National Nursing Home Survey, there are 16,000 certified nursing homes and other long-term care facilities (LTCFs) in the United States, in which approximately 1.5 million older adults reside.1 The majority (88.3%) of nursing home and LTCF residents are 65 years of age and older; 45.2% are 85 years of age and older.1 By the year 2030, it is anticipated that 20% of the United States population will be 65 years of age or older,2 and almost 30 million of these persons will have functional limitations that may require long-term care.3 The impact of influenza is particularly severe among the elderly. Although adults 65 years of age and older represent only 13% of the total US population,4 they account for 63% of influenza-related hospitalizations due to bacterial infections and pulmonary, cardiovascular, and cerebrovascular complications5; 90% of annual influenza-related deaths6; and 64% of the total economic burden of influenza.7 Influenza illness is thought to be the cause of excess mortality due to ischemic heart disease, cerebrovascular disease, and diabetes in adults 70 years of age and older during the winter months.8 The disproportionate burden of influenza in the elderly is due at least in part to immunosenescence, the age-related decline in the immune system that leads to a reduced capacity to fight infection and to develop an adequate protective immune response to vaccine.9-11 The phenomenon of immunosenescence is the rationale for development of a more immunogenic influenza vaccine specifically for people 65 years of age and older. The vaccine, first available in the 2010-2011 influenza season, has 4 times the amount of antigen compared to previously available vaccines and was licensed on the basis of its ability to generate a more robust immune response among people in the 65-and-older age group.12,13
Residents of LTCFs Are Especially Vulnerable Elderly residents of LTCFs may experience even higher morbidity and mortality secondary to influenza and influenza-like illness (ILI) than community-dwelling elderly persons.14 The elderly living in LTCFs often suffer not only from immunosenescence but also from debilitating chronic medical conditions that place them at higher risk of infection and complications. In addition, they are more likely to be exposed to influenza and ILI in the institutional setting. Viruses can be easily introduced and spread via exposure to newly admitted residents, shared caregivers, health care personnel, volunteers, and visitors who circulate between the community and the facility. 3,14,16,17 The closed environment and limited mobility of residents within the facility also contribute to the spread of infection.3,14,15,16 Seasonal attack rates of ILI among residents of LTCFs vary considerably: During years in which no influenza epidemic occurs, an attack rate of 5%-20% is typical. In epidemic years, up to 70% of residents may become ill, and casefatality rates may be as high as 30%.16,17 Before an Outbreak Occurs: Vaccination is Key! Annual vaccination of all residents and staff in LTCFs is the most effective method currently available for reducing the morbidity and mortality associated with influenza infection.9,16 Vaccinated residents of LTCFs who develop ILI often have milder illness of shorter duration than unvaccinated residents, and they are less likely to develop secondary complications or die as a result of their illness.14,17 Even influenza vaccine that is a bad match for the circulating strain can attenuate symptoms, such as fever.18 Vaccinating the staff against influenza can help prevent deaths in residents (Figure 1)19-22 as well