A prospective study on the epidemiology and clinical significance of viral respiratory infections among pediatric oncology patients

Influenza Vaccination Coverage Rates and Determinants in Greek Children until the Age of Ten (2008-2019), the Rhea Mother-Child Cohort

BACKGROUND

In Greece, influenza vaccination is currently recommended for children with high-risk conditions. There are limited data on influenza vaccination uptake among Greek children with and without high-risk conditions. We aim to describe the annual influenza vaccination uptake until the age of ten in a population-based mother-child cohort and identify the factors influencing vaccination rates.

METHODS

Immunization data from the child's health cards at 4 and 10 years were available for 830 and 298 children participating in the Rhea cohort (2008-2019). We calculated vaccination coverage by age, winter season and among children with asthma and obesity for whom the vaccine is indicated. Univariable and multivariable stepwise logistic regression models were utilized to identify the association between several sociodemographic, lifestyle and health-related variables and vaccine uptake by age four.

RESULTS

By the ages of four and ten, 37% and 40% of the children, respectively, had received at least one influenza vaccination. Only 2% of the children were vaccinated for all winter seasons during their first four years of life. The vaccination rate was highest at the age of two and during the 2009-2010 season. Vaccination rates for children with asthma and obesity were 18.2% and 13.3% at age four and 8.3% and 2.9% at age ten. About 10% of all vaccines were administered after December and 24% of the children received only one dose upon initial vaccination. Children with younger siblings and those who had experienced more respiratory infections were more likely to be vaccinated by the age of four, while children exposed to smoking were less likely to be vaccinated.

CONCLUSIONS

Children in our study were more likely to be vaccinated against influenza at an early age with the peak occurring at the age of two. Nonetheless, annual vaccination uptake was uncommon. Vaccination rates of children with asthma and obesity were well below the national target of 75% for individuals with chronic conditions. Certain groups may merit increased attention in future vaccination campaigns such as children raised in families with unfavourable health behaviours.

Impact of COVID-19 Related Restrictions on Infections in Children with Cancer or after Hematopoietic SCTA

BACKGROUND

Infections are a major concern for immunocompromised children. We investigated whether non-pharmaceutical interventions (NPIs) implemented in the general population during the coronavirus disease 2019 (COVID-19) pandemic in Germany had an impact on frequency, type and severity of infections in these patients.

PATIENTS AND METHODS

We analyzed all admissions to the clinic of pediatric hematology, oncology and stem cell transplantation (SCT) with (suspected) infection or fever of unknown origin (FUO) from 2018 to 2021.

RESULTS

We compared a 27-month period before NPIs (Pre-COVID: 01/2018-03/2020; 1041 cases) with a 12-month period with underlying NPIs (COVID: 04/2020-03/2021; 420 cases). During the COVID period the number of in-patient stays with FUO or infections decreased (38,6 cases/month vs. 35,0 cases/month), the median duration of hospital stays was longer (8 d (CI95: 7-8 d) vs. 9 d (CI95: 8-10 d) P=0,02)), the mean number of antibiotics per case increased (2,1 (CI95: 2,0-2,2) vs. 2,5 (CI95: 2,3-2,7); P=0,003)) and a substantial reduction of viral respiratory and gastrointestinal infections per case was seen (0,24 vs. 0,13; P<0,001). Notably, there was no detection of respiratory syncytial virus, influenza and norovirus, between May 2020 and March 2021. Based on need of intensive care measures and further parameters we conclude that severe (bacterial) infections were not significantly reduced by NPIs.

CONCLUSIONS

Introduction of NPIs in the general population during the COVID-pandemic substantially reduced viral respiratory and gastrointestinal infections in immunocompromised patients, while severe (bacterial) infections were not prevented.

Outcomes for paediatric acute leukaemia patients admitted to the paediatric intensive care unit

Children with acute leukaemia (AL) are a high-risk population for infections and life-threatening conditions requiring paediatric intensive care unit (PICU) admission, presenting an increased mortality rate. A few literature exists about PICU outcomes in this kind of patients, especially with haematopoietic stem cell transplant (HSCT) background. We investigated the clinical and epidemiological characteristics of these patients as well as their outcomes. A retrospective, single-centre analytical/observational study was conducted from January 2011 to December 2018 in the PICU of a tertiary care hospital. AL patients from 28 days to 18 years old admitted to the PICU were included, excluding those with histories of HSCT or CAR T-cell therapy. We collected epidemiological and clinical characteristics, laboratory and microbiology results and outcomes. Forty-three patients with AL required urgent admission (35 lymphoblastic and 8 myeloblastic) for 63 different episodes. The main reasons were sepsis (21, 33.3%), hyperleukocytosis (12, 19%), respiratory failure (11, 17.5%) and seizures (8, 12.7%). Nineteen (30.2%) required inotropic support, and fifteen (23.8%) required mechanical ventilation. Three patients died at the hospital (3/43, 6.9%). Sixty-day mortality was 9.3%, and 1-year mortality was 13.9%. There was no differences regarding the type of AL and 60-day mortality (log-rank 2.652, p = 0.103).Conclusion: In our study, the main cause of admission for AL patients was infection, which was associated to more severity and longer hospital admission. What is Known: • Acute leukaemia is the most common childhood cancer. Admission to a paediatric intensive care unit is required in 30% of children with acute leukaemia. • Regarding the outcomes of children with acute leukaemia that require admission to the intensive care unit data are scarce. What is New: • Mortality in acute leukaemia patients admitted to the paediatric intensive care unit is lower than that of patients with a history of stem cell therapy but higher than that of patients with solid tumours. • The main reason for admission was sepsis, which is related in literature to more severity and long length of stay.

Admissions due to vaccine preventable diseases in a large paediatric intensive care unit in Greece over a 10-year period

AIM

Childhood immunisation is an important preventive measure. However, care givers may delay routine immunisations or seek exemptions from state vaccine mandates. Vaccine refusal creates barriers on vaccine coverage and leads to morbidity and mortality.

METHODS

Our study reviews morbidity and mortality from vaccine preventable diseases (VPDs) in a large paediatric intensive care unit in Greece over a 10-year period.

RESULTS

During the study period, 73 cases of VPDs were recorded, corresponding to 3.5% of total paediatric intensive care unit admissions. Influenza was the most prevalent VPD, followed by pneumococcal disease, measles, pertussis and meningococcal disease. Most patients (83.3%) were unvaccinated for the admission's VPD. Outcome was unfavourable for 31.9% of the patients (17 children died, 6 developed chronic impairment).

CONCLUSION

Absent or incomplete vaccination may result in serious morbidity and mortality from preventable diseases. Strengthening vaccination strategies are needed to improve individual protection as well as herd immunity.

Viral Respiratory Infections in Hematological Patients

Viral infections of the respiratory system represent one of the most important complications in hematological patients in terms of both the severity of the clinical picture and its related impact on the duration of hospitalization, and of mortality. The most implicated viruses are those that commonly cause community-based respiratory diseases: respiratory syncytial virus, Influenza virus and rhinovirus. However, in some cases the clinical picture may be triggered by first infection with or reactivation of pathogens normally not responsible for clinically relevant diseases in immunocompetent subjects. This issue is currently being taken into greater consideration within the scientific community. However, the strong heterogeneity in the epidemiology and clinical expression of these infections and the lack of adequate therapeutic options imply that there is currently no uniform consensus on the best management of these patients. The main purpose of this review is to highlight which viruses are currently most implicated in the onset of these infections, what is their incidence in so heterogeneous and fragile patients and the factors that lead to disease's onset and evolution. Possible or available clinical management options, diagnostic and therapeutic tools, and preventive and prophylaxis measures are also discussed.

Frequency of asymptomatic and symptomatic respiratory virus detection in pediatric hematopoietic cell transplant patients

Respiratory viral infections are common and can cause significant morbidity and mortality in pediatric patients undergoing hematopoietic cell transplantation (HCT). The prevalence of disease has been primarily identified from retrospective studies using standard-of-care specimens. The incidence of both asymptomatic respiratory viral detection and symptomatic respiratory viral detection in this high-risk population is not well described. We performed longitudinal, active, prospective surveillance in pediatric HCT patients. Subjects underwent weekly midturbinate swabs (MTSs) for the detection of 18 respiratory viruses and subtypes peri-HCT and 100 days post-HCT. Clinical data were obtained from the medical record. From September 2015 to February 2017, 24 children underwent 29 HCT, and 284 MTSs were collected. Forty-two (15%) specimens were virus-positive from 10 (42%) subjects. Specimens from children undergoing allogeneic HCT were more likely to have a virus detected (17% vs 8%, P = .04) compared with specimens from children undergoing autologous HCT. Sixteen (38%) detections were not associated with symptoms. Almost half (8/17) of the unique viral infections occurred during the HCT hospitalization after a negative specimen, suggesting nosocomial acquisition, and preceded detection from a clinical specimen. Rhinovirus, the most common virus detected, was the only virus detected in 33 (81%) virus-positive specimens; only 11 (33%) rhinovirus detections were asymptomatic. Asymptomatic detection of coronavirus and bocavirus occurred. Asymptomatic respiratory virus detection occurred in more than one-third of the children undergoing HCT. The acquisition of respiratory viruses during HCT hospitalization suggests nosocomial acquisition. Early detection of respiratory viruses during asymptomatic periods could have infection prevention and treatment implications.

Role of Human Bocavirus Respiratory Tract Infection in Hematopoietic Cell Transplant Recipients

BACKGROUND

Limited data exist regarding the impact of human bocavirus (BoV) in hematopoietic cell transplant (HCT) recipients.

METHODS

In a longitudinal surveillance study among allogeneic HCT recipients, pre-HCT and weekly post-HCT nasal washes and symptom surveys were collected through day 100, then at least every 3 months through 1 year post-HCT at the Fred Hutch (2005-2010). Samples were tested by multiplex semi-quantitative PCR for 12 viruses. Plasma samples from BoV+ subjects were analyzed by PCR. Separately, we conducted a retrospective review of HCT recipients with BoV detected in lower respiratory tract specimens.

RESULTS

Among 51 children and 420 adults in the prospective cohort, 21 distinct BoV respiratory tract infections (RTIs) were observed by 1 year post-HCT in 19 patients. Younger age and exposure to children were risk factors for BoV acquisition. Univariable models among patients with BoV RTI showed higher peak viral load in nasal samples (p=0.04) and presence of respiratory copathogens (p=0.03) were associated with presence of respiratory symptoms but BoV plasma detection was not. Only watery eyes and rhinorrhea were associated with BoV RTI in adjusted models. With additional chart review, we identified 6 HCT recipients with BoV detected in lower respiratory tract specimens [incidence rate of 0.4% (9/2509) per sample tested]. Although all cases presented with hypoxemia, 4 had respiratory copathogens or concomitant conditions that contributed to respiratory compromise.

CONCLUSIONS

BoV RTI is infrequent in transplant recipients and associated with mild symptoms. Our studies did not demonstrate convincing evidence that BoV is a serious respiratory pathogen.

HMPV in Immunocompromised Patients: Frequency and Severity in Pediatric Oncology Patients

Cancer is the first cause of death by disease in childhood globally. The most frequent types of cancers in children and adolescents are leukemias, followed by brain and central nervous system tumors and lymphomas. The recovery rate of cancer in children is around 80% in developed countries and up to 30% in developing countries. Some of the main causes of complications in children and adolescents with cancer are respiratory viral infections, mainly in bone marrow-transplanted patients. Respiratory viruses have been detected in the bronchoalveolar lavage or nasal wash specimens from cancer patients with or without respiratory illness symptoms. Human metapneumovirus (HMPV) is within the ten most common viruses that are encountered in samples from pediatric patients with underlying oncology conditions. In most of cases, HMPV is found as the only viral agent, but co-infection with other viruses or with bacterial agents has also been reported. The discrepancies between the most prevalent viral agents may be due to the different populations studied or the range of viral agents tested. Some of the cases of infection with HMPV in cancer patients have been fatal, especially in those who have received a hematopoietic stem cell transplant. This review seeks to show a general view of the participation of HMPV in respiratory illness as a complication of cancer in childhood and adolescence.