Molecular epidemiology and characteristics of respiratory syncytial virus among hospitalized children in Guangzhou, China.

BACKGROUND: Human respiratory syncytial virus (RSV) is a leading cause of acute lower respiratory tract infection and hospitalization, especially in children. Highly mutagenic nature and antigenic diversity enable the RSV to successfully survive in human population. We conducted a molecular epidemiological study during 2017-2021 to investigate the prevalence and genetic characteristics of RSV. METHODS: A total of 6499 nasopharyngeal (NP) swabs were collected from hospitalized children at Department of Pediatrics, Guangdong Provincial Hospital of Traditional Chinese Medicine, Guangzhou, Guangdong, China. All NP swab specimens were preliminary screened for common respiratory viruses and then tested for RSV using specific PCR assays. Partial G genes of RSV were amplified for phylogenetic analysis and genetic characterization. RESULTS: The overall detection rate for common respiratory viruses was 16.12% (1048/6499). Among those, 405 specimens (6.20%, 405/6499) were found positive for RSV. The monthly distribution of RSV and other respiratory viruses was variable, and the highest incidence was recorded in Autumn and Winter. Based on the sequencing of hypervariable region of G gene, 93 RSV sequences were sub-grouped into RSV-A (56, 60.2%) and RSV-B (37, 39.8%). There was no coinfection of RSV-A and RSV-B in the tested samples. Phylogenetic analysis revealed that RSV-A and RSV-B strains belonged to ON1 and BA9 genotypes respectively, indicating predominance of these genotypes in Guangzhou. Several substitutions were observed which may likely change the antigenicity and pathogenicity of RSV. Multiple glycosylation sites were noticed, demonstrating high selection pressure on these genotypes. CONCLUSION: This study illustrated useful information about epidemiology, genetic characteristics, and circulating genotypes of RSV in Guangzhou China. Regular monitoring of the circulating strains of RSV in different parts of China could assist in the development of more effective vaccines and preventive measures.

Pollen antigens and atmospheric circulation driven seasonal respiratory viral outbreak and its implication to the Covid-19 pandemic.

The patterns of respiratory virus illness are expressed differently between temperate and tropical climates. Tropical outbreaks often peak in wet seasons. Temperate outbreaks typically peak during the winter. The prevailing causal hypotheses focus on sunlight, temperature and humidity variations. Yet no consistent factors have been identified to sufficiently explain seasonal virus emergence and decline at any latitude. Here we demonstrate close connections among global-scale atmospheric circulations, IgE antibody enhancement through seasonal pollen inhalation, and respiratory virus patterns at any populated latitude, with a focus on the US. Pollens emerge each Spring, and the renewed IgE titers in the population are argued to terminate each winter peak of respiratory illness. Globally circulated airborne viruses are postulated to subsequently deposit across the Southern US during lower zonal geostrophic winds each late Summer. This seasonally refreshed viral load is postulated to trigger a new influenza outbreak, once the existing IgE antibodies diminish to a critical value each Fall. Our study offers a new and consistent explanation for the seasonal diminishment of respiratory viral illnesses in temperate climates, the subdued seasonal signature in the tropics, the annually circulated virus phenotypes, and the northerly migration of influenza across the US every year. Our integrated geospatial and IgE hypothesis provides a new perspective for prediction, mitigation and prevention of the outbreak and spread of seasonal respiratory viruses including Covid-19 pandemic.

Pediatric Asthma Health Care Utilization, Viral Testing, and Air Pollution Changes During the COVID-19 Pandemic.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic caused dramatic changes in daily routines and health care utilization and delivery patterns in the United States. Understanding the influence of these changes and associated public health interventions on asthma care is important to determine effects on patient outcomes and identify measures that will ensure optimal future health care delivery. OBJECTIVE: We sought to identify changes in pediatric asthma-related health care utilization, respiratory viral testing, and air pollution during the COVID-19 pandemic. METHODS: For the time period January 17 to May 17, 2015 to 2020, asthma-related encounters and weekly summaries of respiratory viral testing data were extracted from Children's Hospital of Philadelphia electronic health records, and pollution data for 4 criteria air pollutants were extracted from AirNow. Changes in encounter characteristics, viral testing patterns, and air pollution before and after Mar 17, 2020, the date public health interventions to limit viral transmission were enacted in Philadelphia, were assessed and compared with data from 2015 to 2019 as a historical reference. RESULTS: After March 17, 2020, in-person asthma encounters decreased by 87% (outpatient) and 84% (emergency + inpatient). Video telemedicine, which was not previously available, became the most highly used asthma encounter modality (61% of all visits), and telephone encounters increased by 19%. Concurrently, asthma-related systemic steroid prescriptions and frequency of rhinovirus test positivity decreased, although air pollution levels did not substantially change, compared with historical trends. CONCLUSIONS: The COVID-19 pandemic in Philadelphia was accompanied by changes in pediatric asthma health care delivery patterns, including reduced admissions and systemic steroid prescriptions. Reduced rhinovirus infections may have contributed to these patterns.

Neonatal outcomes following new reimbursement limitations on palivizumab in Italy.

OBJECTIVE: To evaluate the impact of new reimbursement decisions for palivizumab treatment on respiratory syncytial virus (RSV) hospitalisations and the concomitant number of palivizumab prescriptions for infants aged <2 years. DESIGN: We compared the RSV hospitalisation rates in infants before and after implementation of new limitations during three RSV seasons 2014-2017. SETTING: Population aged <2 years at the beginning of each RSV seasons extracted from regional health systems (Lazio region, 2016, 5 898 124 inhabitants and 47 595 births). PATIENTS: Out of 70 323 infants, 5895 (8.4%) premature babies (gestational age (GA) <37 weeks) were followed before-after Italian Medicines Agency (AIFA)-2016 limitations. INTERVENTION: In 2016, AIFA, following the American Academy of Pediatrics guidelines, decided to limit coverage of palivizumab prophylaxis (GA ≤29 weeks). MAIN OUTCOMES MEASURES: Trend of hospitalisations by months and rate of RSV before-after new restrictions were analysed. Palivizumab prescriptions and costs for National Health Service (NHS) were considered. RESULTS: In a population of 284 902 aged <2 years, the number of hospitalisations due to RSV infection was 1729. Following AIFA-2016 limitations, a reduction in the number of RSV infection-based hospitalisations from 6.3/1000 (95% CI 6.0 to 6.7) to 5.5/1000 (95% CI 5.0 to 5.9) was observed. Palivizumab showed a concomitant reduction of 48% in the number of prescriptions (saving €750 000 for the NHS). No differences of GA, age on admission or severity of RSV infection were observed. CONCLUSIONS: Implementation of the new palivizumab reimbursement criteria was not associated with an increase in the RSV hospitalisation rate for children aged <2 years despite a significant reduction in the number of palivizumab prescriptions.

Vaccines for the Paramyxoviruses and Pneumoviruses: Successes, Candidates, and Hurdles.

Human parainfluenza viruses (family Paramyxoviridae), human metapneumovirus, and respiratory syncytial virus (family Pneumoviridae) infect most infants and children within the first few years of life and are the etiologic agents for many serious acute respiratory illnesses. These virus infections are also associated with long-term diseases that impact quality of life, including asthma. Despite over a half-century of vaccine research, development, and clinical trials, no vaccine has been licensed to date for the paramyxoviruses or pneumoviruses for the youngest infants. In this study, we describe the recent reclassification of paramyxoviruses and pneumoviruses into distinct families by the International Committee on the Taxonomy of Viruses. We also discuss some past unsuccessful vaccine trials and some currently preferred vaccine strategies. Finally, we discuss hurdles that must be overcome to support successful respiratory virus vaccine development for the youngest children.

Effectiveness of Respiratory Syncytial Virus Immunoprophylaxis in Reducing Bronchiolitis Hospitalizations Among High-Risk Infants.

We sought to determine the real-world effectiveness of respiratory syncytial virus (RSV) immunoprophylaxis in a population-based cohort to inform policy. The study population included infants born during 1996-2008 and enrolled in the Kaiser Permanente Northern California integrated health-care delivery system. During the RSV season (November-March), the date of RSV immunoprophylaxis administration and the following 30 days were defined as RSV immunoprophylaxis protected period(s), and all other days were defined as unprotected period(s). Numbers of bronchiolitis hospitalizations were determined using International Classification of Diseases, Ninth Revision, codes during RSV season. We used a proportional hazards model to estimate risk of bronchiolitis hospitalization when comparing infants' protected period(s) with unprotected period(s). Infants who had ever received RSV immunoprophylaxis had a 32% decreased risk of bronchiolitis hospitalization (adjusted hazard ratio = 0.68, 95% confidence interval: 0.46, 1.00) when protected periods were compared with unprotected periods. Infants with chronic lung disease (CLD) had a 52% decreased risk of bronchiolitis hospitalization (adjusted hazard ratio = 0.48, 95% confidence interval: 0.25, 0.94) when protected periods were compared with unprotected periods. Under the new 2014 American Academy of Pediatrics (AAP) guidelines, 48% of infants eligible for RSV immunoprophylaxis on the basis of AAP guidelines in place at birth would no longer be eligible, but nearly all infants with CLD would remain eligible. RSV immunoprophylaxis is effective in decreasing hospitalization. This association is greatest for infants with CLD, a group still recommended for receipt of RSV immunoprophylaxis under the new AAP guidelines.

Recent advances in the development of subunit-based RSV vaccines.

Respiratory syncytial virus (RSV) is a major cause of lower respiratory tract infections causing pneumonia and bronchiolitis in infants. RSV also causes serious illness in elderly populations, immunocompromised patients and individuals with pulmonary or cardiac problems. The significant morbidity and mortality associated with RSV infection have prompted interest in RSV vaccine development. In the 1960s, a formalin-inactivated vaccine trial failed to protect children, and indeed enhanced pathology when naturally infected later with RSV. Hence, an alternative approach to traditional killed virus vaccines, which can induce protective immunity without serious adverse events, is desired. Several strategies have been explored in attempts to produce effective vaccine candidates including gene-based and subunit vaccines. Subunit-based vaccine approaches have shown promising efficacy in animal studies and several have reached clinical trials. The current stage of development of subunit-based vaccines against RSV is reviewed in this article.

Natural history and epidemiology of respiratory syncytial virus infection in the Middle East: Hospital surveillance for children under age two in Jordan.

UNLABELLED: Respiratory syncytial virus (RSV) is the leading cause of bronchiolitis and viral pneumonia in infants and young children worldwide. In the Middle East and Arab countries, the burden of RSV-associated hospitalizations is not well characterized. We sought to determine the burden and clinical/epidemiological characteristics of RSV hospitalization in young children in Amman, Jordan. We investigated risk factors for severity including vitamin D levels. METHODS: We conducted viral surveillance with clinical and demographic data in children <2 years admitted with respiratory symptoms and/or fever at the Al-Bashir Government Hospital from March16, 2010 to March 31, 2013. Nasal/throat swabs were obtained and placed into lysis buffer, and frozen at -80°C until testing by real-time RT-PCR for 11 respiratory viruses. Heel stick blood or sera samples for 25-hydroxyvitamin D [25(OH)D] levels were obtained and sent to a central laboratory for mass spectrometry. RESULTS: Of the 3168 children, >80% testing positive for one virus, with RSV the most common virus detected (44%). The RSV-associated hospitalization rate was highest in children <6 months with an annual range of 21.1-25.9 per 1000, compared to 6.0-8.0 in 6-11-month-olds and 1.6-2.5 in 12-23-month-olds. RSV-positive children compared with RSV-negative were more likely to be previously healthy without underlying medical conditions, less likely to be born prematurely, had a higher frequency of supplemental oxygen use, and had lower median vitamin D levels. Risk factors for oxygen use in RSV-positive children included underlying medical conditions, lack of breastfeeding, younger age, and higher viral load. CONCLUSION: RSV is a major cause of illness in hospitalized Jordanian children and is associated with increased severity compared to other respiratory viruses. Children with RSV in the Middle East would benefit from future RSV vaccines and antiviral therapy.

Surveillance for healthcare-acquired febrile respiratory infection in pediatric hospitals participating in the Canadian Nosocomial Infection Surveillance Program.

OBJECTIVE: To determine the rates of healthcare-acquired febrile respiratory infection (HA-FRI) in Canadian pediatric hospitals and to determine the vaccination status of patients with healthcare-acquired respiratory syncytial virus (RSV) infection, influenza, or pneumococcal infection who were also eligible for immunoprophylaxis. METHODS: Prospective surveillance was conducted in 8 hospitals from January 1 to April 30, 2005. All hospitalized patients less than 18 years of age were eligible, except for patients housed in standard newborn nurseries or psychiatric units. Infection control professionals reviewed laboratory reports, conducted ward rounds, and reviewed medical records to identify case patients. Descriptive analyses were completed, as well. RESULTS: A total of 96 case patients were identified; 52 (54%) were male, and 48 (50%) were aged 1 year or less. Seventy-two patients (75%) had chronic medical conditions. Respiratory viruses accounted for 72 (71%) of 101 pathogens identified, and RSV was the virus most frequently identified. Of these 96 patients, 9 (9%) died, and 3 (3%) of the deaths were related to the patient's HA-FRI. The mean incidence rate was 0.97 infections/1,000 patient-days (range, 0.29-1.50 infections/1,000 patient-days). Only 2 (15%) of 13 influenza vaccine-eligible children who acquired influenza while hospitalized were reported to have been vaccinated, but influenza vaccination status was unknown for most children. However, 4 (80%) of 5 RSV prophylaxis-eligible children who had healthcare-acquired RSV infection had received immunoprophylaxis with anti-RSV monoclonal antibody. CONCLUSIONS: HA-FRI is mainly caused by viruses such as RSV, and it primarily affects children under 1 year of age and those with chronic medical conditions.

Perfil clínico-epidemiológico de las infecciones por virus respiratorios en adultos hospitalizados durante la estación de influenza 2004 / Clinical and epidemiological characteristics of respiratory virus infections among adults hospitalized during 2004 influenza season

El comportamiento epidemiológico del virus influenza (FLU) en la comunidad se refleja en el hospital, es planteable que la actividad comunitaria de otros virus respiratorios también se traduzca en un alza de las internaciones por estos agentes. Objetivo: describir la presencia y características clínico-epidemiológicas de infecciones por virus respiratorios no-FLU (virus respiratorio sincicial-VRS, parainfluenza y adenovirus-ADV) entre adultos hospitalizados durante la temporada de influenza y establecer una comparación con virus influenza-A (IA) o -B (IB). Pacientes y Método: Adultos internados en Hospital Clínico Universidad Católica, de mayo a julio de 2004, con infección por IA o IB, y VRS, parainfluenza (1-2-3) o ADV demostrada por test rápido o inmunofluorescencia directa. Resultados: Se identificaron 86 casos: 73,5 por ciento FLU (48,2 por ciento, IA y 25,3 por ciento IB) y 26,5 por ciento no-FLU. (15,7 por ciento parainfluenza-2; 8,4 por ciento VRS, 1,2 por ciento parainfluenza-3 y 1,2 por ciento ADV). El grupo con FLU presentó más frecuentemente mialgias, tos, hospitalización por síndrome febril, mayores valores de PCR y porcentaje de baciliformes (p < 0,05). Conclusiones: Durante la temporada de influenza 2004, 26,5 por ciento de las infecciones entre adultos hospitalizados fueron causadas por virus no-FLU. La dificultad en diferenciar infecciones por virus FLU de no-FLU, plantea la necesidad de ampliar el estudio de la etiología viral incluso durante la temporada de FLU.

Populations at risk for developing respiratory syncytial virus and risk factors for respiratory syncytial virus severity: infants with predisposing conditions.

According to National Vital Statistics Reports, premature infants (< 36 weeks gestation) account for approximately 7.4% of all births. During the 8 years from 1989 to 1997, multiple births steadily increased across all categories from twin to quintuplet and higher orders. During that same period low birth weight (< 2500 g) births increased almost 12%, and very low birth weight (< 1500 g) births increased approximately 20%.Attendant to these national trends in multiple and preterm births, overall gestation-specific survival rates have improved substantially. This improved outcome can be attributed in large measure to advances in neonatal care and technology. Despite the encouraging statistics on survival, infants born prematurely, at low or very low birth weights and/or with chronic conditions that predispose to lower respiratory tract illness, continue to incur serious risk of long term morbidity and the consumption of inpatient hospital services. In a recent 2-year study of US children, low and very low birth weights were found to be independent risk factors for bronchiolitis-associated mortality. In the past 14 years what defines bronchopulmonary dysplasia (BPD)/chronic lung disease (CLD) has shifted away from clinical, radiographic and pathologic findings in the preterm infant toward the pathophysiology of arrested lung development and the need for supportive care beyond 36 weeks corrected gestational age. The incidence of BPD/CLD ranges from 14 to 43%, with higher rates observed among infants of lower gestational age and birth weight. The health care team approach to the management of BPD directs its efforts toward minimizing pulmonary vascular resistance, alleviating airway obstruction and improving short term lung mechanics. Measures to prevent BPD/CLD attempt to forestall both acute and chronic lung function abnormalities. To that end researchers have investigated the early use of continuous positive airway pressure, vitamin supplementation and recombinant human copper/zinc superoxide dismutase. Despite significant gains in the survival of infants born at lower gestational ages, prematurity, low birth weight and/or underlying chronic pulmonary disease put the pediatric patient at risk for increased frequency and severity of respiratory syncytial virus lower respiratory tract illness and the potential for its long term sequelae.