Respiratory viral infections after hematopoietic stem cell transplantation in children

Respiratory viral infections in children with cancer and febrile neutropenia and children undergoing hematopoietic stem cell transplantation

PURPOSE OF REVIEW

The scope of this review is to understand the epidemiology and potential role of respiratory viral infections in children with cancer and febrile neutropenia, as well as in children, undergoing hematopoietic stem cell transplantation. Early detection of respiratory viral infections through molecular diagnostic techniques has allowed recent randomized clinical studies to advance the possibility of more rational use of antimicrobials in this susceptible population.

RECENT FINDINGS

Progress has been made in the early detection of respiratory viruses in episodes of fever and neutropenia in children with cancer. In selected patients who meet specific clinical safety criteria and have negative bacterial cultures, it has been possible to safely and effectively discontinue antimicrobials. This has been validated in recent randomized clinical studies. However, more evidence is still needed for a similar indication in children, undergoing hematopoietic stem cell transplantation with viral respiratory infection episodes.

SUMMARY

Understanding the role of respiratory viral infections in populations of immunocompromised children may contribute to a more rational use of antimicrobials and, in the near future, may help to decrease antimicrobial resistance in this susceptible population.

Respiratory Syncytial Virus Infections in Recipients of Bone Marrow Transplants: A Systematic Review and Meta-Analysis

Human Respiratory Syncytial Virus (RSV) is a common cause of respiratory tract infections. Usually associated with infants and children, an increasing amount of evidence suggests that RSV can cause substantial morbidity and mortality in immunocompromised individuals, including recipients of bone marrow transplantation (BMT). The present systematic review was therefore designed in accordance with the PRISMA guidelines to collect available evidence about RSV infections in BMT recipients. Three medical databases (PubMed, Embase, and MedRxiv) were therefore searched for eligible observational studies published up to 30 September 2023 and collected cases were pooled in a random-effects model. Heterogeneity was assessed using I2 statistics. Reporting bias was assessed by means of funnel plots and regression analysis. Overall, 30 studies were retrieved, including 20,067 BMT cases and 821 RSV infection episodes. Of them, 351 were lower respiratory tract infections, and a total of 78 RSV-related deaths were collected. A pooled attack rate of 5.40% (95% confidence interval [95%CI] 3.81 to 7.60) was identified, with a corresponding incidence rate of 14.77 cases per 1000 person-years (95%CI 9.43 to 20.11), and a case fatality ratio (CFR) of 7.28% (95%CI 4.94 to 10.60). Attack rates were higher in adults (8.49%, 95%CI 5.16 to 13.67) than in children (4.79%, 95%CI 3.05 to 7.45), with similar CFR (5.99%, 95%CI 2.31 to 14.63 vs. 5.85%, 95%CI 3.35 to 10.02). By assuming RSV attack rates as a reference group, influenza (RR 0.518; 95%CI 0.446 to 0.601), adenovirus (RR 0.679, 95%CI 0.553 to 0.830), and human metapneumovirus (RR 0.536, 95%CI 0.438 to 0.655) were associated with a substantially reduced risk for developing corresponding respiratory infection. Despite the heterogeneous settings and the uneven proportion of adult and pediatric cases, our study has identified high attack rates and a substantial CFR of RSV in recipients of BMT, stressing the importance of specifically tailored preventive strategies and the need for effective treatment options.

Respiratory Viral Infections in the Pediatric Hematopoietic Stem Cell Transplant Population: Progression to Lower Respiratory Tract Disease

BACKGROUND

Respiratory viral infections (RVIs) are important complications in pediatric patients undergoing hematopoietic stem cell transplantation (HSCT); however, risk factors for lower respiratory tract infections (LRTIs) are not well characterized. The aim of this study was to determine risk factors for the progression to LRTIs in pediatric patients with respiratory symptoms who underwent HSCT.

PATIENTS AND METHODS

This retrospective study included 87 pediatric patients with respiratory symptoms who underwent HSCT. Respiratory viral polymerase chain reaction samples were obtained from all patients. The evaluated data included risk factors to progression to LRTIs, long-term pulmonary complications, transplantation-related mortality, and overall survival.

RESULTS

Viral pathogens were detected in 31 (48.4%) patients with upper respiratory tract infections and 13 (56.5%) patients with LRTIs. There was a statistically significant difference between the groups in engraftment delay and lymphocytopenia. Also it was determined that engraftment delay (odds ratio: 7.46 [95% CI, 1.99 to 27.86]; P = 0.003) and COVID-19 infection had statistically significant effects on overall survival in general (odds ratio: 8.06 [95% CI, 2.63 to 24.64]; P <0.001]).

CONCLUSION

Not only host and transplant-related factors but also viral agent type were found to be effective in progression to LRTIs. As the available therapy for respiratory viral infections remains limited, the focus should be on the prevention of infection.

A biomarker panel for risk of early respiratory failure following hematopoietic cell transplantation

This study identified and validated ST2, WFDC2, IL-6, and TNFR1 as risk biomarkers for RF and related mortality post-HCT.

Plasma biomarkers associated with respiratory failure (RF) following hematopoietic cell transplantation (HCT) have not been identified. Therefore, we aimed to validate early (7 and 14 days post-HCT) risk biomarkers for RF. Using tandem mass spectrometry, we compared plasma obtained at day 14 post-HCT from 15 patients with RF and 15 patients without RF. Six candidate proteins, from this discovery cohort or identified in the literature, were measured by enzyme-linked immunosorbent assay in day-7 and day-14 post-HCT samples from the training (n = 213) and validation (n = 119) cohorts. Cox proportional-hazard analyses with biomarkers dichotomized by Youden’s index, as well as landmark analyses to determine the association between biomarkers and RF, were performed. Of the 6 markers, Stimulation-2 (ST2), WAP 4-disulfide core domain protein 2 (WFDC2), interleukin-6 (IL-6), and tumor necrosis factor receptor 1 (TNFR1), measured at day 14 post-HCT, had the most significant association with an increased risk for RF in the training cohort (ST2: hazard ratio [HR], 4.5, P = .004; WFDC2: HR, 4.2, P = .010; IL-6: HR, 6.9, P < .001; and TFNR1: HR, 6.1, P < .001) and in the validation cohort (ST2: HR, 23.2, P = .013; WFDC2: HR, 18.2, P = .019; IL-6: HR, 12.2, P = .014; and TFNR1: HR, 16.1, P = .001) after adjusting for the conditioning regimen. Using cause-specific landmark analyses, including days 7 and 14, high plasma levels of ST2, WFDC2, IL-6, and TNFR1 were associated with an increased HR for RF in the training and validation cohorts. These biomarkers were also predictive of mortality from RF. ST2, WFDC2, IL-6 and TNFR1 levels measured early posttransplantation improve risk stratification for RF and its related mortality.

Hyperglycemia results in decreased immune cell infiltration and increased viral load in the lung in a mouse model of RSV infection

Respiratory Syncytial virus (RSV) infection is a feared disease in vulnerable populations with impaired immune responses. There is currently no vaccine against RSV and young children along with elderly people are at increased risk of severe or sometimes life-threatening RSV infection. Hyperglycemia with immunomodulatory patterns can impact on infectious disease outcomes and immune system responses in diabetic patients. Even though research continues to uncover the complex mechanisms underlying RSV immunopathogenesis and diabetes mellitus disease separately, limited information is available about interaction between these two phenomena. Here, we evaluated the influence of hyperglycemia as the hallmark of diabetes mellitus disease on the pathogenesis and immunopathogenesis of RSV in a mouse model. In this experiment, hyperglycemia was induced by intraperitoneal injection of Streptozotocin (STZ), and after diabetes confirmation, mice were infected with RSV-A2, and the immune responses were followed for 5 days until the mice were sacrificed. Analyses on airway immune cell influx, T-Lymphocyte subtypes, cytokines secretion, lung histopathology, and viral load were conducted. Our results showed that hyperglycemia resulted in reduced lung immune cells infiltration totally and it was associated with decreased pathological damage of the lung. Following RSV infection in hyperglycemic mice, the ratio of CD4/CD8 T-Lymphocytes due to CD8+ depletion, increased. Furthermore, the level of IFN-γ and IL-17A cytokines decreased, whereas IL-10 showed an upward trend and the viral load increased in hyperglycemic mice compared with normoglycemic mice. In conclusion, these findings indicate that hyperglycemia can ameliorate and downregulate RSV-induced inflammatory and antiviral responses, and result in increment of viral load.

Multiple Reactivations of Viral Infections Followed by Cerebral Toxoplasmosis After Allogeneic Hematopoietic Stem Cell Transplantation in an Adolescent With Ph(+) Acute Lymphoblastic Leukemia: A Case Report

After allogeneic hematopoietic stem cell transplantation (allo-HSCT), especially from an unrelated donor, infectious complications are frequent and severe, sometimes with fatal outcomes. Despite using highly sensitive molecular techniques for close monitoring in the early post-transplant period for early diagnosis, not every viral infection or reactivation can be detected adequately early, even with highly sensitive methods. Particularly after toxic and deeply immunosuppressive treatment, multiple infections or reactivations, uncommon infections, or infections in unusual locations can occur. Here, we present a case of multiple viral infections or reactivations and cerebral toxoplasmosis in a 17-year-old youth with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) treated with allo-HSCT who suffered multiple viral infections followed by cerebral toxoplasmosis.

Respiratory Syncytial Virus Prophylaxis in Immunocompromised Children: Outcomes From the Canadian RSV Evaluation Study of Palivizumab Registry Over Twelve Seasons (2005-2017)

BACKGROUND

Immunocompromised children are at increased risk for respiratory syncytial virus (RSV) infection with associated morbidity and mortality. Prophylaxis is usually provided to these children on a case-by-case basis.

METHODS

Immunocompromised children who received ≥1 injection of palivizumab were prospectively enrolled across 32 Canadian sites, between 2005 and 2017, during the RSV season. We assessed respiratory illness hospitalization (RIH) and RSV-related hospitalization (RSVH) hazard ratios (HRs) in immunocompromised children versus infants' prophylaxed for standard indications (SI: prematurity ≤35 weeks' gestation, bronchopulmonary dysplasia, and congenital heart disease) and complex medical disorders (CMD). Data were analyzed using t-tests, χ and Cox proportional hazards adjusted for confounders.

RESULTS

A total of 25,003 infants were recruited; 214 immunocompromised, 4283 CMD, 20,506 SI. On average, children received 4.4 ± 1.3 injections. A total of 16,231 children were perfectly adherent (58.4% immunodeficiency, 68.9% CMD, 64.2% SI; P < 0.0005). A higher proportion of immunocompromised children were aboriginal and exposed to smoking compared with CMD and SI. Immunocompromised children also had a higher median; gestational and enrollment age and birth weight compared with CMD and SI. Immunodeficient children had a higher RIH risk compared with SI (HR = 2.4, 95% confidence interval, 1.3-4.7, P = 0.009) but were similar to CMD (HR = 1.7, 95% confidence interval, 0.9-3.4, P = 0.118). RSVH in prophylaxed, immunocompromised children was similar to CMD (HR < 0.005, P = 0.955) and SI (HR < 0.005, P = 0.953).

CONCLUSIONS

Immunocompromised children who received palivizumab had an increased RIH hazard compared with the SI group. Similar RSVH hazard between the 3 groups suggests that immunocompromised children may benefit from palivizumab during the RSV season.

Epidemiology, Outcome and Risk Factors Analysis of Viral Infections in Children and Adolescents Undergoing Hematopoietic Cell Transplantation: Antiviral Drugs Do Not Prevent Epstein-Barr Virus Reactivation

Objective

The analysis of epidemiology, risk factors and outcome of viral infections in children and adolescents after hematopoietic cell transplantation (HCT).

Methods

In this multicenter nationwide study a total of 971 HCT procedures (741 allo-HCT; 230 auto-HCT) over a period of 6 years were analyzed.

Results

During this period 801 episodes of viral infections were diagnosed in 442 patients. The incidence of viral infections was 57.9% in allo-HCT and 4.8% in auto-HCT patients. The most frequent infections after allo-HCT were caused by cytomegalovirus (CMV), polyoma BK virus (BKV) and Epstein-Barr virus (EBV). The majority of infections occurred within the first 4 months after allo-HCT and over 80% required pharmacotherapy or symptomatic therapy. The median time of treatment of specific viral infection ranged from 7 (for EBV) to 24 (for CMV) days. The highest mortality was observed in case of CMV infection. The risk factors for viral infections were allo-HCT, acute leukemia, acute and chronic graft versus host disease (a/cGVHD), and matched unrelated donor (MUD)/mismatched unrelated donor (MMUD)-HCT. The risk factor for death from viral infection were CMV-IgG seropositivity in acute lymphoblastic leukemia recipient, and MUD/MMUD-HCT. The incidence of EBV infection requiring pre-emptive treatment with rituximab in allo-HCT children was 19.3%. In 30.8% cases of EBV infection, these episodes were preceded by other viral infection and treated with antivirals, which did not prevent development of EBV-DNA-emia with need of rituximab treatment in 81.5% cases. In 47.7% of these cases, GVHD was a factor enabling development of significant EBV-DNA-emia during antiviral therapy of other infection.

Conclusion

We have shown that antiviral drugs do not prevent EBV reactivation in allo-HCT pediatric patients.

Use of whole-genome sequencing in the molecular investigation of care-associated HCoV-OC43 infections in a hematopoietic stem cell transplant unit

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HCoV−OC43 is involved in healthcare–associated infections.

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HCoV−OC43 genotypes B, E, F and G are identified.

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Asian and European strains of HCoV−OC43 circulate among patients.

Background

While respiratory viral infections are recognized as a frequent cause of illness in hematopoietic stem cell transplantation (HSCT) recipients, HCoV−OC43 infections have rarely been investigated as healthcare-associated infections in this population.

Objectives

In this report, HCoV−OC43 isolates collected from HSCT patients were retrospectively characterized to identify potential clusters of infection that may stand for a hospital transmission.

Study design

Whole-genome and S gene sequences were obtained from nasal swabs using next-generation sequencing and phylogenetic trees were constructed. Similar identity matrix and determination of the most common ancestor were used to compare clusters of patient’s sequences. Amino acids substitutions were analysed.

Results

Genotypes B, E, F and G were identified. Two clusters of patients were defined from chronological data and phylogenetic trees. Analyses of amino acids substitutions of the S protein sequences identified substitutions specific for genotype F strains circulating among European people.

Conclusions

HCoV−OC43 may be implicated in healthcare-associated infections.

Are Community Acquired Respiratory Viral Infections an Underestimated Burden in Hematology Patients?

Despite a plethora of studies demonstrating significant morbidity and mortality due to community-acquired respiratory viral (CRV) infections in intensively treated hematology patients, and despite the availability of evidence-based guidelines for the diagnosis and management of respiratory viral infections in this setting, there is no uniform inclusion of respiratory viral infection management in the clinical hematology routine. Nevertheless, timely diagnosis and systematic management of CRV infections in intensively treated hematology patients has a demonstrated potential to significantly improve outcome. We have briefly summarized the recently published data on CRV infection epidemiology, as well as guidelines on the diagnosis and management of CRV infections in patients intensively treated for hematological malignancies. We have also assessed available treatment options, as well as mentioned novel agents currently in development.

Antigenic Site-Specific Competitive Antibody Responses to the Fusion Protein of Respiratory Syncytial Virus Were Associated With Viral Clearance in Hematopoietic Cell Transplantation Adults

Background: Recent studies of human sera showed that the majority of the respiratory syncytial virus (RSV) neutralizing antibodies are directed against pre-fusion conformation of the fusion (F) protein of RSV and revealed the importance of pre-fusion antigenic site Ø specific antibodies. However, detailed analysis of multiple antigenic site-specific competitive antibody responses to RSV F protein and their contribution to virus clearance in humans are lacking. Methods: We prospectively enrolled a cohort of RSV infected hematopoietic cell transplantation (HCT) adults (n = 40). Serum samples were collected at enrollment (acute, n = 40) and 14 to 60 days post-enrollment (convalescent, n = 40). Antigenic site-specific F protein antibodies were measured against pre-fusion site Ø, post-fusion site I, and sites II and IV present in both the pre-fusion and post-fusion F protein conformations utilizing four different competitive antibody assays developed with biotinylated monoclonal antibodies (mAb) D25, 131-2A, palivizumab, and 101F, respectively. The lower limit of detection were 7.8 and 1.0 μg/mL for the competitive antibody assays that measured site Ø specific response, as well as sites I, II, and IV specific responses, respectively. Neutralizing antibody titers to RSV A and B subgroups was determined by microneutralization assays. Results: The overall findings in RSV infected HCT adults revealed: (1) a significant increase in antigenic site-specific competitive antibodies in convalescent sera except for site Ø competitive antibody (p < 0.01); (2) comparable concentrations in the acute and convalescent serum samples of antigenic site-specific competitive antibodies between RSV/A and RSV/B infected HCT adults (p > 0.05); (3) significantly increased concentrations of the antigenic site-specific competitive antibodies in HCT adults who had genomic RSV detected in the upper respiratory tract for <14 days compared to those for ≥14 days (p < 0.01); and (4) statistically significant correlation between the antigenic site-specific competitive antibody concentrations and neutralizing antibody titers against RSV/A and RSV/B (r ranged from 0.33 to 0.83 for acute sera, and 0.50-0.88 for convalescent sera; p < 0.05). Conclusions: In RSV infected HCT adults, antigenic site-specific antibody responses were induced against multiple antigenic sites found in both the pre-fusion and post-fusion F conformations, and were associated with a more rapid viral clearance and neutralizing antibody activity. However, the association is not necessarily the cause and the consequence.

Respiratory Virus Infections in Hematopoietic Cell Transplant Recipients

Highly immunocompromised pediatric and adult hematopoietic cell transplant (HCT) recipients frequently experience respiratory infections caused by viruses that are less virulent in immunocompetent individuals. Most of these infections, with the exception of rhinovirus as well as adenovirus and parainfluenza virus in tropical areas, are seasonal variable and occur before and after HCT. Infectious disease management includes sampling of respiratory specimens from nasopharyngeal washes or swabs as well as sputum and tracheal or tracheobronchial lavages. These are subjected to improved diagnostic tools including multiplex PCR assays that are routinely used allowing for expedient detection of all respiratory viruses. Disease progression along with high mortality is frequently associated with respiratory syncytial virus, parainfluenza virus, influenza virus, and metapneumovirus infections. In this review, we discuss clinical findings and the appropriate use of diagnostic measures. Additionally, we also discuss treatment options and suggest new drug formulations that might prove useful in treating respiratory viral infections. Finally, we shed light on the role of the state of immune reconstitution and on the use of immunosuppressive drugs on the outcome of infection.

A multicenter investigation of respiratory syncytial viral infection in children with hematopoietic cell transplantation

BACKGROUND

Hematopoietic cell transplant (HCT) may be a risk factor for morbidity and mortality from respiratory syncytial virus (RSV). Previous studies have been limited by small sample size. We took a multicenter approach with the goal of better understanding the epidemiology, risk factors, treatment, morbidity, and mortality associated with RSV infections among children with HCT in the United States.

METHODS

A retrospective, multicenter, cohort study of pediatric HCT recipients were diagnosed with RSV infection between January 2010 and December 2014.

RESULTS

Of the 1522 HCT, 47 (3%) patients were diagnosed with RSV. Of those with RSV, 9 (19.1%) were admitted to the pediatric intensive care unit (PICU), 6 (12.8%) received invasive mechanical ventilation, and 1 died. Prophylactic palivizumab was uncommon. All who required critical care received ribavirin vs 7.3% of those who did not (P = .004). Cobacterial infections were found in 16 patients and were not associated with the need for critical care. We examined potential risk factors for severity of RSV disease. In those who received invasive ventilation, 100% had one of the preidentified risk factors. Half of those requiring mechanical ventilation were diagnosed with RSV during their conditioning for transplant as opposed to only 2.4% of those that did not require invasive mechanical ventilation (P = .005).

CONCLUSIONS

In this multicenter cohort, RSV was not common in children following HCT. Few children infected with RSV required critical care and mortality was low. Those diagnosed with RSV during conditioning for transplant were at higher risk for invasive mechanical ventilation.

Human metapneumovirus infections in hematopoietic cell transplant recipients and hematologic malignancy patients: A systematic review

Over the past decade, reported incidence of human metapneumovirus (hMPV) has increased owing to the use of molecular assays for diagnosis of respiratory viral infections in cancer patients. The seasonality of these infections, differences in sampling strategies across institutions, and small sample size of published studies make it difficult to appreciate the true incidence and impact of hMPV infections. In this systematic review, we summarized the published data on hMPV infections in hematopoietic cell transplant recipients and patients with hematologic malignancy, focusing on incidence, hMPV-associated lower respiratory tract infection (LRTI), mortality, prevention, and management with ribavirin and/or intravenous immunoglobulins. Although the incidence of hMPV infections and hMPV-associated LRTI in this patient population is similar to respiratory syncytial virus or parainfluenza virus and despite lack of directed antiviral therapy, the mortality rate remains low unless patients develop LRTI. In the absence of vaccine to prevent hMPV, infection control measures are recommended to reduce its burden in cancer patients.

Parainfluenza virus infections in hematopoietic cell transplant recipients and hematologic malignancy patients: A systematic review

Parainfluenza viral infections are increasingly recognized as common causes of morbidity and mortality in cancer patients, particularly in hematopoietic cell transplant (HCT) recipients and hematologic malignancy (HM) patients because of their immunocompromised status and susceptibility to lower respiratory tract infections. Advances in diagnostic methods, including polymerase chain reaction, have led to increased identification and awareness of these infections. Lack of consensus on clinically significant endpoints and the small number of patients affected in each cancer institution every year make it difficult to assess the efficacy of new or available antiviral drugs. In this systematic review, we summarized data from all published studies on parainfluenza virus infections in HM patients and HCT recipients, focusing on incidence, risk factors, long-term outcomes, mortality, prevention, and management with available or new investigational agents. Vaccines against these viruses are lacking; thus, infection control measures remain the mainstay for preventing nosocomial spread. A multi-institutional collaborative effort is recommended to standardize and validate clinical endpoints for PIV infections, which will be essential for determining efficacy of future vaccine and antiviral therapies.

Respiratory syncytial virus infections in pediatric transplant recipients: A Canadian Paediatric Surveillance Program study

The incidence and spectrum of severity of RSV infections in SOT or HSCT recipients is not known. From September 2010 through August 2013, pediatricians were surveyed monthly by the CPSP for SOT or HSCT recipients with RSV infection within two yr post-transplant. There were 24 completed case report forms that fit the inclusion criteria (10 HSCT and 14 SOT recipients). Six of 24 cases (25%) remained outpatients, and 11 (46%) were managed on an inpatient ward, while seven (29%) required intensive care of which five required mechanical ventilation and two died of RSV infection. Ten of 23 cases (43%) were nosocomial with these data not recorded for one case. Many transplant recipients recover uneventfully from RSV infection in the first two yr post-transplant. However, severe disease and death also occur. Larger studies are required to establish risk factors for poor outcomes. Prevention of nosocomial RSV should be a priority in transplant recipients.

Antiviral T-cell therapy

Serious viral infections are a common cause of morbidity and mortality after allogeneic stem cell transplantation. They occur in the majority of allograft recipients and are fatal in 17–20%. These severe infections may be prolonged or recurrent and add substantially to the cost, both human and financial, of the procedure. Many features of allogeneic stem cell transplantation contribute to this high rate of viral disease. The cytotoxic and immunosuppressive drugs administered pretransplant to eliminate the host hematopoietic/immune system and any associated malignancy, the delay in recapitulating immune ontogeny post‐transplant, the immunosuppressive drugs given to prevent graft versus host disease (GvHD), and the effects of GvHD itself, all serve to make stem cell transplant recipients vulnerable to disease from endogenous (latent) and exogenous (community) viruses, and to be incapable of controlling them as quickly and effectively as most normal individuals.

Respiratory syncytial virus infections in infants affected by primary immunodeficiency

Primary immunodeficiencies are rare inherited disorders that may lead to frequent and often severe acute respiratory infections. Respiratory syncytial virus (RSV) is one of the most frequent pathogens during early infancy and the infection is more severe in immunocompromised infants than in healthy infants, as a result of impaired T- and B-cell immune response unable to efficaciously neutralize viral replication, with subsequent increased viral shedding and potentially lethal lower respiratory tract infection. Several authors have reported a severe clinical course after RSV infections in infants and children with primary and acquired immunodeficiencies. Environmental prophylaxis is essential in order to reduce the infection during the epidemic season in hospitalized immunocompromised infants. Prophylaxis with palivizumab, a humanized monoclonal antibody against the RSV F protein, is currently recommended in high-risk infants born prematurely, with chronic lung disease or congenital heart disease. Currently however the prophylaxis is not routinely recommended in infants with primary immunodeficiency, although some authors propose the extension of prophylaxis to this high risk population.

Human rhino- and enteroviruses in children with respiratory symptoms in Luanda, Angola

OBJECTIVES

The role of human rhinoviruses (HRV) and human enteroviruses (HEV) in common colds, as well as their seasonality, remains largely unknown in tropical environments. The study aimed to define the frequency and clinical features of HRV and HEV in children with respiratory symptoms in tropical Africa during autumn and winter.

METHODS

Clinical data and PCR assays of nasopharyngeal swabs (NPS) were collected from 67 (66%) children with and 35 (34%) children without chronic illnesses who were attending different outpatient clinics at a paediatric tertiary-care hospital in Luanda, Angola.

RESULTS

Thirty-six (35%) children had HIV infection, and 27 (26%) were malnourished. Thirty-seven (36%) out of 102 NPS specimens were virus-positive: 34 (33%) for HRV and 10 (10%) for HEV. Seven (7%) had co-infection. The highest HRV-positivity rate (47%) occurred in July (P = 0·02), a mid-winter month with high relative humidity but no precipitation. Virus positivity was associated with younger age (median 36 vs 52 months, P = 0·02) but not with specific symptoms or findings.

CONCLUSIONS

HRVs play a major role in young children's respiratory infections in urban tropical Angola during autumn and winter. A better understanding is required of the seasonality and clinical outcomes of these viruses in children living in resource-poor tropical countries.

North-South divide: distribution and outcome of respiratory viral infections in paediatric intensive care units in Cape Town (South Africa) and Nottingham (United Kingdom)

AIM

This study aims to describe and compare the spectrum, course, seasonality and outcome of children with virus-associated respiratory symptoms (VARS) admitted to two paediatric intensive care units (PICUs) in the United Kingdom (UK) and South Africa (SA).

METHODS

Cross-sectional study of routinely collected data on subjects admitted to PICU with respiratory symptoms and positive respiratory viral polymerase chain reaction between July 2009 and July 2011.

RESULTS

Six hundred forty-six samples yielding 765 viral isolates (74% from SA) from 599 patients (53% male; median (interquartile range) age 6.0 (2.3-16.5) months) were included. Rhinovirus, respiratory syncytial virus and adenovirus were most commonly isolated. Adenovirus was more prevalent in SA (24.3% vs. 16.8%, P = 0.03). Possible or likely nosocomial viral acquisition occurred in 78% of isolates in SA versus 48% in the UK (P < 0.0001).Total mortality was 13.5%; 17% in SA versus 4% in the UK (P < 0.0001). Mortality for community acquired VARS was 8.4% versus 16.1% in those with possible nosocomial viral acquisition (P = 0.009). Factors independently associated with mortality were: SA study site (adjusted odds ratio (OR) 3.4, 95% confidence interval (CI) 1.4-8.5; P = 0.008); age (months) (OR 1.0, 95% CI 1.0-1.02; P = 0.001); Paediatric Index of Mortality 2 score (%) (OR 1.0, 95% CI 1.01-1.03; P = 0.0002) and isolation of adenovirus (OR 3.0, 95% CI 1.8-5.0; P < 0.0001).

CONCLUSIONS

The outcome of children with VARS was worse in SA compared with the UK PICU. Nosocomial VARS was highlighted as an important concern and requires further investigation.

Prolonged respiratory viral shedding in transplant patients

Respiratory viral infections are frequent causes of morbidity in transplant patients. We screened symptomatic adult transplant recipients for respiratory viruses in a cohort of patients attending a referral medical center in Brazil. The duration of viral shedding and the prevalence of viral codetections were also determined. During a 1‐year period (2011–2012), swabs were obtained from 50 patients. An in‐house polymerase chain reaction panel designed to detect 10 viruses was used. Viruses were identified in 19 (38%) patients, particularly parainfluenza III (32%) and the respiratory syncytial virus (20%); multiple viruses were identified in 26% of patients. Prolonged viral shedding was observed with 60% of individuals excreting viruses for >10 days. The clinical and epidemiologic relevance of prolonged viral shedding remains to be determined.