RSV Infection In Children Research Articles

Infant-derived human nasal organoids exhibit relatively increased susceptibility, epithelial responses, and cytotoxicity during RSV infection

BackgroundRespiratory syncytial virus (RSV) causes significant morbidity and mortality, especially in young children. Why RSV infection in children is more severe compared to healthy adults is not fully understood. MethodsWe used ex-vivo human nasal organoid platforms from infants and adults to investigate the underlying mechanism of this disease disparity at the initial site of RSV replication, the nasal epithelium. ResultsInfant-derived human nasal organoid-air liquid interface (HNO-ALIs) lines were more susceptible to early RSV replication. Moreover, infant-derived HNO-ALIs elicited a statistically significant greater overall cytokine response, enhanced mucous production, and greater cellular damage compared to their adult counterparts. Furthermore, the adult cytokine response was associated with a superior regulatory cytokine response, which could explain less cellular damage than in infant lines. ConclusionsOur data highlights substantial differences in how infant and adult upper respiratory tract epithelium responds to RSV infection at the cellular level. These differences in epithelial cellular response can lead to impaired mucociliary clearance, a more dysregulated innate immune response predisposing infants to more severe RSV infection compared to adults.

Machine learning clinical decision support systems for surveillance: a case study on pertussis and RSV in children.

We tested the performance of a machine learning (ML) algorithm based on signs and symptoms for the diagnosis of RSV infection or pertussis in the first year of age to support clinical decisions and provide timely data for public health surveillance. We used data from a retrospective case series of children in the first year of life investigated for acute respiratory infections in the emergency room from 2015 to 2020. We collected data from PCR laboratory tests for confirming pertussis or RSV infection, clinical symptoms, and routine blood testing results, which were used for the algorithm development. We used a LightGBM model to develop 2 sets of models for predicting pertussis and RSV infection: for each type of infection, we developed one model trained with the combination of clinical symptoms and results from routine blood test (white blood cell count, lymphocyte fraction and C-reactive protein), and one with symptoms only. All analyses were performed using Python 3.7.4 with Shapley values (Shap values) visualization package for predictor visualization. The performance of the models was assessed through confusion matrices. The models were developed on a dataset of 599 children. The recall for the pertussis model combining symptoms and routine laboratory tests was 0.72, and 0.74 with clinical symptoms only. For RSV infection, recall was 0.68 with clinical symptoms and laboratory tests and 0.71 with clinical symptoms only. The F1 score for the pertussis model was 0.72 in both models, and, for RSV infection, it was 0.69 and 0.75. ML models can support the diagnosis and surveillance of infectious diseases such as pertussis or RSV infection in children based on common symptoms and laboratory tests. ML-based clinical decision support systems may be developed in the future in large networks to create accurate tools for clinical support and public health surveillance.

The Long-Term Healthcare Utilization and Economic Burden of RSV Infection in Children ≤5 Years in Japan: Propensity Score Matched Cohort Study.

The objective of this study was to estimate the long-term healthcare utilization and cost burden of RSV by chronological age of diagnosis (Year 1, Year 2 and Years 3-5 cohorts) as well as by gestational age at birth in Japan. The JMDC database was used to retrospectively identify RSV and control patients between February 1, 2011 and January 31, 2016 and follow them through December 31, 2017. Infants with RSV infection (n = 9028 in Year 1; n = 4929 in Year 2; n = 2004 in Years 3-5) were matched to controls (n = 17,886; n = 9351; n = 3655, respectively) based on gestational age and year and quarter of birth; controls were assigned the index date (ie, diagnosis) of their respective match. Covariate-balancing propensity score weights were employed adjusting for remaining imbalances between cohorts. The main outcomes were average cumulative rates for all-cause, asthma/wheezing, and respiratory-related hospitalizations, physician and urgent care/emergency visits and associated costs (reported as 2018 ¥JPY) over 36-months of follow-up since index. Healthcare utilization was significantly higher among RSV cases for most comparisons. All-cause average differential cost burden was higher for RSV, compared to controls, among the following cohorts: Year 1 full-term (¥277,727); Year 2 preterm (¥530,302), late preterm (¥270,797), full-term (¥238,832); Years 3-5 preterm (¥110,057), late preterm (¥486,670), full-term (¥289,986). While all-cause costs were similar for preterm and late preterm children in the Year 1 cohort, respiratory- and asthma/wheezing-related attributable costs were substantially higher for RSV. RSV infection had a significant long-term health and economic burden among children infected during their first year of life and later in life. Study findings have import for prevention strategies, currently directed at maternal immunization and monoclonal antibodies for preventing primary RSV infections in the first six months of life and beyond but also for older age not targeted currently.

Respiratory syncytial virus: host genetic susceptibility and factors associated with disease severity in a cohort of pediatric patients.

Respiratory syncytial virus (RSV) infections are the leading cause of hospitalization in young children. We assessed the epidemiology, severity, clinical characteristics, molecular profile and genetic factors of RSV infections compared to acute respiratory illness (ARI) caused by other respiratory viruses. Prospective cohort study was conducted from 2017 to 2018 with children under 2 years old hospitalized with ARI. Detection of respiratory viruses was carried out using RT-PCR. RSVs were genotyped via nucleotide sequencing, and host interleukin 28B (IL28B) single nucleotide polymorphisms (SNPs) were determined using SNP TaqMan® Genotyping Assays. A total of 468 children were included; 288 (61.5%) had an infection by a single virus: 202 (70.1%) cases by RSV followed by rhinovirus 36 (12.5%) and influenza 16 (5.6%). Of the RSV cases, 36% were genotyped with a higher prevalence of RSV B (62.1%). The RSV group presented median age of 2.7 months (1.6-6.8), higher frequency in: intensive care unit admission (p = 0.004), mechanical ventilation use (p = 0.018), wheezing (p < 0.001), antimicrobial use (p < 0.001) and low oxygen saturation (p < 0.001). Prematurity (27.2%) was the most frequent comorbidity. RSV patients without comorbidities demonstrated a higher frequency in the combination of IL28B rs12979860 CT/IL28B rs8099917 TG and IL28B rs12979860 TT/IL28B rs8099917 TT genotypes. Viral coinfection was detected in 27 (5.7%) children, with the most frequent being RSV and rhinovirus (14.2%). This study highlighted the burden of RSV infection in children under 2 years of age, without comorbidities, with a higher need for pediatric ICU admission. Some IL28B allele combinations had a significant association with RSV frequency of infections.

Burden of respiratory syncytial virus-associated lower respiratory infections in children in Spain from 2012 to 2018

BackgroundRespiratory syncytial virus (RSV) is a major cause of acute lower respiratory tract infection (ALRI) leading to infant hospitalization, morbidity and postnatal mortality in children younger than 5 years of age worldwide. The aim of this study was to collect data on hospitalizations for RSV-related ALRI in children in Spain from 2012 to 2018.MethodsWe used the discharge reports from the Minimum Basic Data Set (MBDS) to retrospectively analyze hospital discharge data in children ≤ 14 years of age with a diagnosis of acute lower respiratory tract infection, based on the ICD-9-CM and ICD-10-CM diagnosis codes, from 2012 to 2018.ResultsA total of 190,474 children, 58.1% boys and 41.9% girls, were admitted for lower respiratory tract infections in Spain, including 118,731 cases of bronchiolitis, 53,972 cases of bronchitis, 3710 cases of RSV-positive pneumonia, and 14,061 cases of RSV infections. Of these, 92,426 children (48.5%) had laboratory-confirmed RSV infection. The mean case fatality rate was almost 6 times higher for pneumonia (0.6%) than for bronchiolitis (0.1%) or bronchitis (0.1%). A significant linear increase in the mean annual hospitalization rate for pneumonia of almost 15% per year was found, with no changes in the trend over the study period.ConclusionsRSV-related respiratory infections remain a leading cause of infant hospitalization in Spain. Effective antiviral treatments and preventive vaccines are urgently needed for the management of RSV infection in children, especially for those aged 6 to 12 months.

1497. Epidemiology of RSV infection in Japan: A nationwide claims database analysis

BackgroundRespiratory syncytial virus (RSV) is the major global cause of hospitalization for bronchiolitis and pneumonia in infancy around the globe. In Japan, the occurrence of RSV infection is monitored under the national pediatric sentinel surveillance system. However, this system does not provide detailed information about patient distribution by month of birth and clinical features. We aimed to describe the national epidemiology and clinical features of RSV infection in children < 24 months of age utilizing a nationwide healthcare claims database in Japan.MethodsWe retrospectively analysed anonymized claims data from the Japan Medical Data Center (JMDC) of medical insurance beneficiaries who had at least one confirmed RSV-related diagnosis by ICD10 codes between January 2017 and December 2018. In children < 24 months of age, the number of patients by age in Japan was estimated using the prevalence of patients in the database and national population data by age.ResultsIn the JMDC database, 9,711 and 8,509 children < 24 months of age had an RSV-related diagnosis in 2017 and 2018, respectively. Of which, 2,473 (25%) and 2,083 (24%) were hospitalized. When extrapolated to the entire Japanese population, an estimated 138,059 and 119,205 RSV-related diagnoses and 33,355 and 27,339 RSV-associated hospitalizations occurred in Japan in 2017 and 2018, respectively. Infants < 6 months of age accounted for between 39% and 42% of total hospitalisations for RSV. A peak in RSV hospitalization was observed at age 2 months. Only 10% of all children < 24 months of age who were hospitalised with an RSV infection had a specific underlying medical condition (preterm infant, bronchopulmonary dysplasia, Down syndrome, chronic heart disease, immunodeficiency). The estimated rate of RSV-associated hospitalization was 35.4 per 1000 population per year among infants < 6 months of age.ConclusionIn conclusion, 3 to 4 out of every 100 Japanese children aged < 6 months were hospitalized for RSV. Ninety percent of children < 24 months of age hospitalised with RSV infection did not have a recognised underlying medical condition. The peak of hospitalization for RSV infection occurred at 2 months of age. Thus, broad-based prevention strategies targeting young infants are needed.DisclosuresYasuhiro Kobayashi, MS, Pfizer (Employee, Shareholder) Kanae Togo, PhD, Pfizer (Employee) Yasmeen Agosti, MD, Pfizer (Employee, Shareholder) John M. McLaughlin, PhD, Pfizer (Employee, Shareholder)

Cold Weather Viruses.

1. Asif Noor, MD* 2. Theresa Fiorito, MD* 3. Leonard R. Krilov, MD*,† 1. *Department of Pediatrics, Children's Medical Center, NYU Winthrop Hospital, Mineola, NY 2. †Department of Pediatrics, State University of New York, Stony Brook School of Medicine, Stony Brook, NY * Abbreviations: AAP: : American Academy of Pediatrics Adv: : adenovirus CDC: : Centers for Disease Control and Prevention FDA: : Food and Drug Administration hMPV: : human metapneumovirus PCR: : polymerase chain reaction PIV: : parainfluenza virus RSV: : respiratory syncytial virus RV: : rhinovirus Clinicians must learn to identify viral infections in children during the winter months and must practice caution with the use of unnecessary medications in such cases. Recognition of the clinical pattern of viral infection (eg, bronchiolitis) in conjunction with judicious use of viral tests (either office-based immunoassays or newer molecular tests) may assist in epidemiological monitoring, cohorting patients in the hospital, withholding unnecessary therapies, and providing a definitive diagnosis. After completing this article, readers should be able to: 1. Review the epidemiological aspects and clinical signs and symptoms of common cold weather viruses. 2. Recognize situations in which viral testing is indicated. 3. Recognize situations in which treatment is indicated. In early November you are evaluating a 9-month-old boy born at 33 weeks of gestation. The infant presents with 2 days of fevers (101°F–102°F [38.3°C–38.8°C]), copious rhinorrhea, and 1 day of coughing with difficulty breathing. He is otherwise feeding well and has had adequate urination. His 4-year-older sister has an upper respiratory tract infection. On physical examination, the infant has a respiratory rate of 45 breaths/min without chest wall retractions. On auscultation there is good air entry with scattered rhonchi bilaterally. What is the most appropriate next step in management? 1. Obtain respiratory syncytial virus (RSV) and influenza antigen testing. 2. Obtain a chest radiograph to look for focal infiltrate. 3. Provide supportive care with nasal …

Etiological structure of influenza and other ARVI in St. Petersburg during epidemic seasons 2012-2016.

The etiological structure of influenza and other acute respiratory viral infections including their rate of incidence in St. Petersburg and Leningrad region during 4 epidemic seasons has been studied. Seasonality of some respiratory viruses was shown and peaks of circulation of RSV, adenovirus, parainfluenza viruses, rhinovirus, bocavirus, metapneumovirus and coronavirus were marked. The interference of influenza A viruses and RSV, RSV and rhinoviruses was highlighted. A high incidence of adenovirus infection in organized communities and RSV infection in children was revealed.

A Recombinant G Protein Plus Cyclosporine A-Based Respiratory Syncytial Virus Vaccine Elicits Humoral and Regulatory T Cell Responses against Infection without Vaccine-Enhanced Disease.

Respiratory syncytial virus (RSV) infection can cause severe disease in the lower respiratory tract of infants and older people. Vaccination with a formalin-inactivated RSV vaccine (FI-RSV) and subsequent RSV infection has led to mild to severe pneumonia with two deaths among vaccinees. The vaccine-enhanced disease (VED) was recently demonstrated to be due to an elevated level of Th2 cell responses following loss of regulatory T (Treg) cells from the lungs. To induce high levels of neutralizing Abs and minimize pathogenic T cell responses, we developed a novel strategy of immunizing animals with a recombinant RSV G protein together with cyclosporine A. This novel vaccine induced not only a higher level of neutralizing Abs against RSV infection, but, most importantly, also significantly higher levels of Treg cells that suppressed VED in the lung after RSV infection. The induced responses provided protection against RSV challenge with no sign of pneumonia or bronchitis. Treg cell production of IL-10 was one of the key factors to suppress VED. These finding indicate that G protein plus cyclosporine A could be a promising vaccine against RSV infection in children and older people.

O-020 Human Coronaviruses Infection In Acute Lower Respiratory Tract Infection In Children

<h3>Objectives</h3> To explore the effects of HCoVs (including HCoV-OC43, HCoV-229E, HCoV-NL63 and HCoV-HKU1) in acute lower respiratory tract infection (ALRTI) in children and to investigate the clinical features of paediatric ALRTI caused by HCoVs. <h3>Methods</h3> Total 3503 cases with ALRTI from March 2007 to March 2010 in Beijing Children’s Hospital Affiliated to Capital Medical University were enrolled into this study. One nasopharyngeal aspirate specimen was collected from each patient. PCR (or RT-PCR) were used to detect respiratory viruses including respiratory syncytial virus, human rhinovirus, influenza virus type A, B and C, parainfluenza virus type 1–4, adenovirus, enterovirus, human coronavirus, human metapneumovirus and human bocavirus. Clinical manifestation and laboratory findings of patients with HCoVs were analysed by using SPSS 19.0 for Windows (SPSS Inc., USA). <h3>Results</h3> The overall positive rate of HCoVs infection was 3.77%. Most cases with HCoVs infection were under 3 years old. The ratio between male and female were 2.3:1, and the rate of co-infection with other respiratory virus in patient infected HCoVs was 65.2%. The positive rate of HCoV-OC43 and HCoV-229E were higher than that of HCoV-NL63 and HCoV-HKU1. There were no significant differences of clinical manifestation, laboratory findings and severity between ALRTIs caused by HCoVs and RSV. <h3>Conclusions</h3> The overall infection rate of HCoVs in ALRTI in children was low. The clinical manifestations, laboratory findings and severity of ALRTI caused by HCoVs were comparable to that of ALRTI with RSV infection in children.

Efficacy of palivizumab prophylaxis among infants with congenital heart disease: A case control study.

Palivizumab prophylaxis for RSV has been consistently reported to reduce the risk of hospital admissions related to RSV infection in children with symptomatic cardiac disease. This study was designed to investigate the efficacy of palivizumab prophylaxis among infants with congenital heart disease (CHD) in Turkey. A total of 91 infants with CHD who received palivizumab prophylaxis and 96 infants with CHD without prophylaxis (0-12 months:52; 12-24 months:44) were included in this single-center retrospective case control study. Data on patient characteristics, household environment, and LRTIs were evaluated. In patients without prophylaxis, the rate of overall lower respiratory tract infections (LRTIs) (P < 0.001), complicated LRTIs (P = 0.006), LRTI-related hospitalization (P < 0.001) and ICU admission (P = 0.008) were significantly higher than control patients. Weight <10th percentile (odds ratio (OR) 5.78, 95% confidence interval (CI):1.37; 24.4, P < 0.001) and concomitant chromosome abnormality (OR 4.01, 95% CI:1.01;16.45, P < 0.001) in patients with prophylaxis, while presence of a sibling <11 years of age (OR 3.38, 95% CI: 1.21; 9.46, P < 0.001) and congestive heart failure (OR 8.63, 95% CI: 2.81; 26.6, P < 0.001) in the control group were the significant correlates of LRTI-related hospitalization. Our findings revealed significantly lower rate of overall and complicated LRTIs, LRTI-related hospitalization and ICU admissions in infants with CHD via palivizumab prophylaxis.

Increased Risk of RSV Infection in Children with Down's Syndrome: Clinical Implementation of Prophylaxis in the European Union

Prospective cohort studies show that Down's syndrome (DS) is an independent risk factor for hospitalization for RSV bronchiolitis. It is unknown whether this observation has been translated into specific management for DS children. The primary goal was to assess the knowledge of healthcare providers in the European Union about RSV infection in DS children and to determine whether it influenced the implementation of prophylaxis. DS caregivers were surveyed using a standardized questionnaire, and country-specific guidelines were obtained. Fifty-three caregivers participated. Thirty-nine (86.7%) had knowledge of the increased risk of severe RSV infection in DS children, and 30 (71.4%) graded that it was important to have a statement on the use of RSV prophylaxis in existing guidelines. Twenty-eight participants had a local DS guideline; hard copies of twelve unique guidelines were obtained. Only one (8.3%) contained a statement on RSV prophylaxis for DS, and five considered such a statement for the next version. Conclusion. Most pediatricians had knowledge that DS children have an increased risk of severe RSV infection. Despite the lack of a specific RSV prophylaxis trial in DS, they felt that a statement on RSV prophylaxis in DS guidelines was important, but this was rarely present in current guidelines.

Clinical manifestation of acute otitis media associated with RSV infection in children

Clinical manifestation of acute otitis media associated with RSV infection in children

Epidemiology of respiratory syncytial virus in children ≤2 years of age hospitalized with lower respiratory tract infections in the Russian Federation: a prospective, multicenter study.

BackgroundRespiratory syncytial virus (RSV) is the leading cause of severe lower respiratory tract infections among infants and young children, and is responsible for an estimated four million deaths per year globally. A monthly injection of palivizumab has been used for prophylaxis of serious RSV infections among high-risk children in 71 countries since 1998 and approval for use in the Russian Federation was obtained in February 2010. A recommendation for RSV prophylaxis in the Russian Federation would require knowledge of the prevalence and seasonality of RSV in that country.MethodsIn a prospective, multicenter, epidemiological study of the prevalence, seasonality, and peak occurrence of RSV infection, children aged ≤2 years hospitalized for lower respiratory tract infections in three regions of the Russian Federation, from September 2008 through April 2009, were screened and tested for RSV using rapid immunochromatography of nasopharyngeal lavage. For subjects who were tested positive, hospitalization data were collected.ResultsOf 519 children aged ≤2 years enrolled from September 11, 2008 through April 26, 2009, 197 tested positive for RSV (38.0%, 95% CI: 33.8, 42.3). The onset of the 2008–2009 RSV season in the Russian Federation occurred in late October 2008, similar to what is observed in other northern temperate zones. Peak activity occurred in early April 2009, when 62% of children enrolled tested positive for RSV.ConclusionThe prevalence of serious RSV infections in the Russian Federation is similar to the prevalence previously identified in other temperate zones of the northern hemisphere. The seasonality of disease shifted towards early spring, with peak activity later in the season, within a range reported in other countries. These data provide further evidence of serious RSV infection in children in the Russian Federation, as well as guidance for timing of seasonal RSV prophylaxis, especially among individuals at high risk for serious RSV infection.

Polymorphisms of interferons and their receptors in the genetics of severe RSV-associated diseases

Because of their important role in the pathophysiology of severe RSV infection, IFNs represent an ideal group of candidate genes for determining RSV disease severity. We studied 14 polymorphisms within 7 genes involved in IFNs signalling. Our study populations consisted of 156 infants with severe RSV infection and 296 healthy control children. None of the genes showed association with severe RSV infection in children. Thus, despite the involvement of different IFNs in the pathophysiology of RSV infection, genetic variants in IFNG and related genes might not alter the risk for the development of severe RSV-associated diseases.

Cost Effectiveness of Palivizumab for Respiratory Syncytial Virus Prophylaxis in High-Risk Children

To assess the cost effectiveness of palivizumab (a preventative treatment against severe respiratory syncytial virus [RSV] infection) in children at high risk of hospitalisation, i.e. preterm infants < or = 35 weeks gestation, children with bronchopulmonary dysplasia (BPD) and children with congenital heart disease (CHD). A decision tree model was developed employing data sources from the published literature, palivizumab clinical trials, official UK price/tariff lists and national population statistics. The comparator was no prophylaxis. The primary perspective of the study was that of the UK NHS. In a societal perspective scenario analysis, the future lost productivity of a child resulting from RSV-related mortality (indirect costs) was also included. The cost of administration of palivizumab, hospital care for RSV infections and the cost of asthma treatment were included. The analysis was based on a lifetime follow-up period in order to capture the impact of palivizumab on long-term morbidity and mortality resulting from an RSV infection. The primary efficacy outcome in the palivizumab clinical trials was the number of RSV hospitalisations avoided, which was extrapolated to effectiveness outcomes, i.e. number of life-years gained and number of QALYs. Costs and effects were discounted by 3.5%. In preterm infants and children with BPD, prophylaxis with palivizumab compared with no prophylaxis had an incremental cost-effectiveness ratio (ICER) of 7042 pounds/QALY without discounting outcomes, increasing to 16,720 pounds/QALY after discounting. In babies with CHD, the use of palivizumab resulted in an ICER of 2427 pounds/QALY without discounting outcomes and 6664 pounds/QALY after discounting. One-way sensitivity analyses and probabilistic sensitivity analyses confirmed the robustness of the model. A scenario analysis showed that the inclusion of indirect costs leads to further improvement in the cost-effectiveness outcomes for palivizumab. This study suggests that palivizumab prophylaxis against severe RSV infection in children at high risk may be cost effective from the NHS perspective (vs no prophylaxis), and that the positive clinical and economic benefits may persist beyond one RSV season.

RSV infection in children has effects for up to two months

RSV infection in children has effects for up to two months

Respiratory Syncytial Virus: Old Challenges and New Approaches

Better therapies and prevention strategies are needed to decrease the burden of acute RSV disease in all age populations worldwide. Furthermore, we can hypothesize that those improved measures also would likely have an effect on the chronic consequences of RSV infection in children and will reduce the incidence of recurrent wheezing and persistent pulmonary function abnormalities caused by RSV LRIs.

Regional impact of prophylaxis with the monoclonal antibody palivizumab on hospitalisations for respiratory syncytial virus in infants.

Palivizumab is approved in Switzerland for prevention of hospitalisation for RSV infection in children with one of the following risk factors: (1) history of prematurity < or = 35 weeks and age < or = 6 months or (2) chronic lung disease and age < or = 1 year. Regional data on the expected effectiveness of this monoclonal antibody are not available. (1) Retrospective, descriptive, single-site study on the characteristics of RSV hospitalisations during two consecutive seasons. (2) Extrapolation of data to generate population-based estimates on the impact of palivizumb if used according to the approved indications. Of 242 RSV hospitalisations, 216 (89.3%) and 26 (10.7%) occurred in children without and with risk factors, respectively. Patients without and with risk factors had similar clinical courses with respect to ICU admission rate (11.6 vs. 11.5%) and rate of mechanical ventilation (3.2 vs. 3.8%). Of a total of 28 ICU admissions, 13 (46%) occurred among infants aged < or = 1 month without risk factors. Former premature infants were significantly older than patients with longer gestation (median age 7.5 vs. 3.7 months, p = 0.026). Applying the approved age criteria would have excluded 10 of 26 patients (38.5%) from eligibility for palivizumab. During the 1999/2000 RSV season, 36% of hospitalisations occurred after April 1, 2000. None of them may have been preventable had prophylaxis been started before November 1, 1999 and carried out for 5 months as recommended. In an annual birth cohort of 10,000, palivizumab as indicated would be expected to prevent between 5 and 7 RSV hospitalisations. The impact of palivizumab on the prevention of RSV hospitalisations in the Canton of Bern, Switerland, is expected to be small, and the approved indications may not target infants at greatest risk for severe disease.

Regional impact of prophylaxis with the monoclonal antibody palivizumab on hospitalisations for respiratory syncytial virus in infants.

Palivizumab is approved in Switzerland for prevention of hospitalisation for RSV infection in children with one of the following risk factors: (1) history of prematurity < or = 35 weeks and age < or = 6 months or (2) chronic lung disease and age < or = 1 year. Regional data on the expected effectiveness of this monoclonal antibody are not available. (1) Retrospective, descriptive, single-site study on the characteristics of RSV hospitalisations during two consecutive seasons. (2) Extrapolation of data to generate population-based estimates on the impact of palivizumb if used according to the approved indications. Of 242 RSV hospitalisations, 216 (89.3%) and 26 (10.7%) occurred in children without and with risk factors, respectively. Patients without and with risk factors had similar clinical courses with respect to ICU admission rate (11.6 vs. 11.5%) and rate of mechanical ventilation (3.2 vs. 3.8%). Of a total of 28 ICU admissions, 13 (46%) occurred among infants aged < or = 1 month without risk factors. Former premature infants were significantly older than patients with longer gestation (median age 7.5 vs. 3.7 months, p = 0.026). Applying the approved age criteria would have excluded 10 of 26 patients (38.5%) from eligibility for palivizumab. During the 1999/2000 RSV season, 36% of hospitalisations occurred after April 1, 2000. None of them may have been preventable had prophylaxis been started before November 1, 1999 and carried out for 5 months as recommended. In an annual birth cohort of 10,000, palivizumab as indicated would be expected to prevent between 5 and 7 RSV hospitalisations. The impact of palivizumab on the prevention of RSV hospitalisations in the Canton of Bern, Switerland, is expected to be small, and the approved indications may not target infants at greatest risk for severe disease.