Respiratory syncytial virus infection in adults

PURPOSE OF REVIEW: Respiratory syncytial virus has increasingly been recognized as a clinically significant cause of respiratory tract infections in adults, especially among the elderly and the immunocompromised. RECENT FINDINGS: Advances in molecular diagnostic methods have enabled rapid diagnosis of respiratory syncytial virus for clinical and epidemiological studies. Recent reports focus on clinical, immunological, and/or radiographic characterizations of respiratory syncytial virus infection in adults, particularly in hospitalized patients and those with underlying chronic obstructive pulmonary disease, and therapeutic and prophylactic use of antiviral agents in immunocompromised adults. Respiratory syncytial virus vaccine development remains a high priority, with the testing of genetically engineered live attenuated vaccines leading to further insights into the pathogenesis of respiratory syncytial virus in adults. SUMMARY: Further studies are necessary to elucidate the pathogenesis and immune response against respiratory syncytial virus in adults. The significant burden of respiratory syncytial virus-induced disease in adults and the limited number of approved antiviral agents reinforce the need to develop a respiratory syncytial virus vaccine.     

Respiratory syncytial virus infection in adults

Respiratory syncytial virus (RSV), an enveloped RNA virus in the Paramyxovirus family, is the most important cause of lower respiratory tract infection in infants and young children, accounting for ~100,000 pediatric hospitalizations and 250 deaths annually in the United States. Despite primarily being recognized as a pediatric pathogen, RSV reinfection causes substantial disease in all adult populations, including healthy young persons, old and frail individuals, those with chronic obstructive pulmonary disease and immunocompromised patients. Most illnesses are mild in adults, but significant morbidity and mortality can develop. In contrast to infants, diagnosis of RSV infections is difficult due to low virus shedding, and optimal diagnosis requires molecular tests. Unfortunately, antiviral therapy is of limited benefit. Ribavirin and palivizumab are the only approved pharmacological agents for RSV treatment and prophylaxis, respectively, and are primarily used in infants; data regarding their usefulness in adults are limited. Currently, specific antiviral therapy is generally reserved for severely immunocompromised patients or severe respiratory failure. The greatest promise for reducing the impact of RSV in adults may be through immunization. However, an effective vaccine for RSV is not currently available.     

Respiratory syncytial virus infection in immunocompromised adults

Respiratory syncytial virus disease was documented in 11 immunocompromised adults, aged 21 to 50. Underlying conditions included bone marrow transplant (6 patients), renal transplant (3 patients), renal and pancreas transplants (1 patient), and T-cell lymphoma (1 patient). Diagnosis of infection was based on specimens from bronchoalveolar lavage, sputum, throat, sinus aspirate, and lung biopsy. The virus was detected simultaneously by antibody in either an immunofluorescence or enzyme-linked immunosorbent assay in 3 of 4 patients whose culture results were positive for respiratory syncytial virus. The virus was an unexpected finding, despite widespread infection in the community. Clinical symptoms included low-grade fever, nonproductive cough, rhinorrhea or nasal congestion, and radiographic evidence of interstitial infiltrates and sinusitis. Aerosolized ribavirin therapy was used in the 6 recipients of bone marrow transplants, 3 of whom required assisted ventilation but died. Death caused by virus infection was documented in 4 of 11 patients. Respiratory syncytial virus disease must be considered in the differential diagnosis of fever and pulmonary infiltrates in immunocompromised adults.     

Respiratory syncytial virus infection in bone marrow transplantation: a case report (syncytial virus infection)

The authors describe the case of a patient receiving a second bone marrow transplantation for acute lymphoblastic leukemia who developed, in the early post transplant period, an interstitial pneumonia caused by respiratory syncytial virus. The patient promptly recovered, but radiological findings of interstitial pneumonia lasted for three months.     

Respiratory syncytial virus infection in tropical and developing countries

Little is known about the epidemiology of respiratory syncytial virus (RSV) infection in tropical and developing countries; the data currently available have been reviewed. In most studies, RSV was found to be the predominant viral cause of acute lower respiratory tract infections (ALRI) in childhood, being responsible for 27– 96% of hospitalised cases (mean 65%) in which a virus was found. RSV infection is seasonal in most countries; outbreaks occur most frequently in the cold season in areas with temperate and Mediterranean climates and in the wet season in tropical countries with seasonal rainfall. The situation on islands and in areas of the inner tropics with perennial high rainfall is less clear-cut. The age group mainly affected by RSV in developing countries is children under 6 months of age (mean 39% of hospital patients with RSV). RSV-ALRI is slightly more common in boys than in girls. Very little information is available about the mortality of children infected with RSV, the frequency of bacterial co-infection, or the incidence of further wheezing after RSV. Further studies on RSV should address these questions in more detail. RSV is an important pathogen in young children in tropical and developing countries and a frequent cause of hospital admission. Prevention of RSV infection by vaccination would have a significant impact on the incidence of ALRI in children in developing countries.     

Respiratory syncytial virus infection following hematopoietic stem cell transplantation

Respiratory syncytial virus, one of the most common causes of respiratory infections in immunocompetent individuals, is frequently spread to recipients of HSCT by family members, other patients, and health care workers. In immunosuppressed individuals, progression from upper respiratory tract disease to pneumonia is common, and usually fatal if left untreated. We performed a retrospective analysis of RSV infections in recipients of autologous or allogeneic transplants. The incidence of RSV following allogeneic or autologous HSCT was 5.7% and 1.5%, respectively. Of the 58 patients with an RSV infection, 16 of 21 patients identified within the first post-transplant month, developed pneumonia. Seventy-two percent of patients received aerosolized ribavirin and/or RSV-IGIV, including 23 of 25 patients diagnosed with RSV pneumonia. In this aggressively treated patient population, three patients died of RSV disease, each following an unrelated HSCT.     

Respiratory syncytial virus infection in an adult with Wegener's granulomatosis.

Respiratory syncytial virus (RSV) has been documented as a pathogen in adults who are immunocompromised because of various underlying conditions. To our knowledge, this is the first report of a patient with Wegener's granulomatosis (WG) and RSV infection resulting in a fatal outcome.     

Viral infection and asthma: Respiratory syncytial virus and wheezing illness

A strong link between bronchiolitis and asthma has been indicated. Bronchiolitis that occurs in infants is manifested physiologically by a widespread narrowing of the air passages and, clinically, by asthma-like symptoms.The major cause of bronchiolitis is respiratory syncytial virus infection. While the precise pathophysiologic sequences of infection are incomplete, many observations have suggested that there is an infiltration of eosinophils in the airways. Current studies have shown that the respiratory syncytial virus penetrates the pulmonary defenses and initiates immunologic responses. The histamine and leukotriene mediators that are released produce an inflammatory reaction and the chemotactic factors bring eosinophils to the site of the reaction. Degranulation of eosinophils can release eosinophil cationic protein into the airways. Our finding that chemoattractants for eosinophils, interleukin-8 and RANTES (regulated upon activation, normal T cell expressed and presumably secreted) were detected in nasopharyngeal aspirates of infants with bronchiolitis suggests that such chemokines from epithelial cells may induce an eosinophil infiltration in the airway. Similar allergic inflammatory changes have been observed in asthma and in epithelial cells infected with respiratory viruses. Future investigation of the mechanism by which bronchiolitis can induce asthma will provide benefits in the treatment and prevention of asthma in sensitive individuals.     

呼吸道合胞病毒与支气管哮喘

支气管哮喘是严重危害人类健康的呼吸系统疾病之一,研究表明,呼吸道合胞病毒(RSV)是成人及婴幼儿下呼吸道感染最常见的病原体之一;近年来研究显示,RSV感染是儿童支气管哮喘发生的重要危险因素之一,并可引起成人哮喘喘息症状加重,鉴于RSV感染在支气管哮喘发生、发展中的重要作用,本人将从RSV感染及其由此导致的免疫功能失常、AHR、黏液分泌等方面加以综述。     

Respiratory syncytial virus infections in adults

In a retrospective 10-year study of 57 adult patients admitted to Orebro Medical Center Hospital, Sweden, with RS virus infections, pneumonia was diagnosed in 36. A primary episode of obstructive airway symptoms was observed in 20% of the patients with pneumonia. Several patients had a long period of fever and a protracted stay in the hospital. No fatal cases or serious complications were registered. Compromised hosts did not appear to be overrepresented in the material, nor did patients with impaired immune responses seem to be more seriously ill. Laboratory findings indicated that the RS virus pneumonia in adults was in some cases due to a mixed bacterial and RS virus infection, but in a few cases it was caused by the RS virus alone. Positive epidemiologic findings were found only in a few cases. The length of the period between the seasonal peak incidences of RS virus infection varied. A tendency to recurrent long and short intervals between the peak incidences was observed. An IgM antibody response to RS virus was common, and IgM detection was found to be a useful complement in the diagnosis of RS virus disease.