Treatment of RSV pneumonia in adults - Evidence of ribavirin effectiveness?

The literature regarding RSV pneumonitis treatment in adults with aerosolized ribavirin does not include studies that were randomized or controlled but rather involves reports in small groups of treated patients. An RSV pneumonitis diagnosis was usually determined by signs, symptoms, and chest X-rays consistent with pneumonitis and positive RSV antigen tests and/or cultures using endotracheal tube aspirates or BAL specimens. For the case series, the percentage of surviving patients treated with aerosolized ribavirin alone, with aerosolized ribavirin and IVIG, and with intravenous ribavirin ranged from 31% to 50%, 17% to 58%, and 20%, respectively. The percentage of surviving nontreated patients ranged from 0% to 100%, where the survivors generally were reported to be less sick or less immunocompromised than nonsurvivors. Factors that complicate the evaluation of effectiveness of ribavirin therapy include inconsistent reporting of information regarding concomitant infections and the use of other antimicrobial agents. Survival of patients treated with aerosolized ribavirin therapy generally was associated with earlier diagnosis of RSV pneumonitis when compared with nonsurvivors, treatment duration of greater than five days, and treatment initiation prior to respiratory failure. In a Phase I study, the use of intravenous ribavirin in RSV pneumonitis did not appear to be any more beneficial than aerosolized ribavirin in adult bone marrow transplant patients, and the incidence of hemolysis prevents recommendation for its use. Comparison of outcomes between treated and nontreated patients or between the use of aerosolized ribavirin alone and aerosolized ribavirin with IVIG is difficult because of the size and nature of the reports; however, the high mortality associated with RSV pneumonitis in immunocompromised adults in these reports suggest that the benefit of ribavirin therapy, with or without IVIG, is small. Of note is the fact that eradication of the RSV virus did not always guarantee survival, which further complicates the use of ribavirin in adult patients. RSV pneumonitis in adults, especially bone marrow transplant patients, is often fatal. However, because of the questionable effectiveness and issues of noncompliance and nonacceptance of ribavirin in adults, the high cost of therapy, and the known difficulties associated with administration, recommendation for the routine use of aerosolized ribavirin therapy cannot be made for adults with RSV pneumonitis. A subset of patients who may gain benefit from aerosolized ribavirin therapy, with or without IVIG, are those diagnosed relatively quickly from onset of symptoms (i.e., within 4-5 d) and who have not developed respiratory failure. Because RSV pneumonitis continues to produce significant mortality in immunocompromised patients, controlled trials are necessary in order to establish a standard of care for these patients.