Post-transplant Viral Respiratory Infections in the Older Patient: Epidemiology, Diagnosis, and Management

Abstract

Organ and stem cell transplantation has been one of the greatest advances in modern medicine, and is the primary treatment modality for many end-stage diseases. As our population ages, so do the transplant recipients, and with that comes many new challenges. Respiratory viruses have been a large contributor to the mortality and morbidity of solid organ transplant (SOT) and hematopoietic stem cell transplant (HSCT) recipients. Respiratory viruses are generally a long-term complication of transplantation and primarily acquired in the community. With the emergence of molecular methods, newer respiratory viruses are being detected. Respiratory viruses appear to cause severe disease in the older transplant population. Influenza vaccine remains the mainstay of prevention in transplant recipients, although immunogenicity of current vaccines is suboptimal. Limited therapies are available for other respiratory viruses. The next decade will likely bring newer antivirals and vaccines to the forefront. Our goal is to provide the most up to date knowledge of respiratory viral infections in our aging transplant population.

Respiratory Viruses Cause Late Morbidity in Recipients of Hematopoietic Stem Cell Transplantation

“…Common respiratory viral infections (CRVIs) contribute to significant morbidity and mortality following hematopoietic stem cell transplantation (HSCT) [1][2][3][4]. T cell-mediated immune responses, including cytotoxic and helper T-lymphocyte activity, are the primary defense against viral infections.…”

“…Factors contributing to the development and severity of a CRVI include type of HSCT (auto versus allo), the specific virus isolated, underlying hematologic malignancy, conditioning regimen, and the stem cell source for allo-HSCT recipients [2,[7][8][9][10]. The apparent increase in incidence of CRVI over the past 10 to 15 years could be attributed to widespread use of sensitive multiplex PCR to detect multiple viral (and bacterial) respiratory tract pathogens [3].…”

Respiratory Viruses in Solid Organ Transplant Recipients

“…In a study of 93 LTRs, 5/93 had respiratory viruses identified in bronchoalveolar lavage using viral culture and DFA staining, whereas 48/93 had respiratory viruses identified by NAT on the same samples [6]. Using multiplex NAT allows testing for several viruses simultaneously with a turnaround time of only 12-24 h [4]. Rapid antigen tests, allowing results within minutes, are clinically available for influenza and RSV only and suffer from low sensitivity [8].…”

“…Parainfluenza virus (PIV) is a single-stranded RNA virus of the Paramyxoviridae family. There are four serotypes of PIV (1-4); serotype 3 is the most common and shows no seasonality and has been associated with outbreaks, whereas serotypes 1 and 2 appear in the fall and winter [4,71]. As with other respiratory viruses, PIV infection was mainly studied in LTRs, where it accounts for 3.6-20.9% of the respiratory viruses isolated [1,2,6].…”

“…In organ transplant recipients, the incidence of respiratory viral infections in transplant ranges between 0.76-0.91 episodes per patient-year [1][2][3], although part of the studies also included asymptomatic infections. The incidence appears to be higher among lung transplant recipients (LTRs) [4], but is not affected by time from transplant [1]. Respiratory viruses are present throughout the year, but there is a higher incidence in the autumn and winter, and patterns differ between viruses [2].…”