The burden of illness due to a variety of viral respiratory pathogens in the elderly population is increasingly being recognized. Influenza and respiratory syncytial virus (RSV), in particular, have most commonly been found to be the leading culprits of viral lower respiratory illness (LRI). However, through the use of novel diagnostic methods, other viruses have been added to the list of significant pathogens in older adults, including parainfluenza (PIV), human rhinoviruses, coronaviruses, and human metapneumovirus (hMPV). Overall, viruses have been implicated in 13% to 31%1, 2
of LRI in elderly adults. Influenza and RSV alone have been estimated to cause approximately 53,800 deaths3
each year in the Unites States. Older adults may not present with the typical “common cold” symptoms that are associated with viral infections.1, 2, 4-13
Rather, the clinical picture may be dominated by lower respiratory tract symptoms or decompensation of chronic medical conditions. Illness in this age group represents reinfection since all were infected as children and hence, many have partial immunity. Due to preexisting mucosal antibodies, lower viral loads may present in respiratory secretions making diagnosis challenging is this age group.
The identification of viral infections in older adults is of practical importance for a number of reasons. First and foremost, isolation of subjects with highly contagious viral infections, such as influenza, is crucial in the inpatient and long term care settings to prevent transmission of disease to frail and debilitated patients, as well as to healthcare workers. Secondly, the diagnosis of influenza can help guide antiviral treatment for individual patients. Prompt diagnosis of influenza is also critical in long term care facilities (LTCF) and other closed populations in the event institutional chemoprophylaxis is needed to limit outbreaks. Although antiviral treatments are not currently available for the other respiratory viruses, diagnosis of these agents may also be increasingly important as more efforts are made to curtail unnecessary antibiotic use.13, 14
Despite recent advances in diagnostic methods, specific viral diagnosis often remains elusive in older populations. This paper will summarize what is known about the diagnosis of viral respiratory diseases in elderly adults with the hope of increasing understanding of the utility and limitations of the currently-available diagnostic tests for viral respiratory pathogens, such as culture, rapid antigen testing, polymerase chain reaction (PCR) test, and serologic analysis. will summarize this review.
Summary of Test Characteristics of Different Diagnostic Tests for Various Respiratory Viral Pathogens in Older Adults