Respiratory Syncytial Virus Admissions Research Articles

Nirsevimab effectiveness against hospital admission for respiratory syncytial virus bronchiolitis in infants

Respiratory syncytial virus (RSV) bronchiolitis is the leading cause of hospitalization in infants. This season, a long half-life monoclonal antibody (Nirsevimab) is available to prevent this disease for all infants born from 1 April-30 September to 2023 and all those born during RSV season (October2023- March 2024). The aim of this study was to evaluate the impact of the implementation of this antibody on RSV admissions in a tertiary hospital. Observational, retrospective and analytical study. All patients <6 months in October admitted for bronchiolitis at 2 time points were included: T1 or Pre-nirsevimab time: 1 September 2015-30 September 2023 and T2 or Nirsevimab time: 1 October-31 December 2023. Total admissions due to any cause of infants <6 months in the same period were used as the reference population. To assess the impact of the implementation of nirsevimab, we calculated the reduction in the percentage of admissions due to RSV with respect to total admissions in both periods, and also in the 2023-2024 season we calculated the double negative test to calculate the effectiveness of the intervention (1-Odds ratio) x 100. In infants under 6 months of age, we found significant differences in the number of admissions for RSV bronchiolitis between the last season and the previous 7 seasons [574/1195 (48%) vs 6/138 (4.3%); p<0.01, RPI: 91%). In the 2023/2024 season, the effectiveness of nirsevimab in preventing admission for RSV bronchiolitis in children under 6 months of age was 85% (CI 95%: 32-97%). The implementation of nirsevimab has had an important impact on the number of hospital admissions for RSV bronchiolitis. There were no differences in the severity of bronchiolitis.

Unraveling the Role of Viral Interference in Disrupting Biennial RSV Epidemics in Northern Stockholm.

Respiratory syncytial virus (RSV) primarily impacts infants and older adults, with seasonal winter outbreaks in temperate countries. Biennial cycles of RSV activity have also been identified in Northern Europe and some states in the United States. Delayed RSV activity was reported worldwide during the 2009 influenza pandemic, and a disrupted biennial pattern of RSV activity was observed in northern Stockholm following the pandemic. Biennial patterns shifted to early/large outbreaks in even-numbered years and late/small outbreaks in odd-numbered years. However, the mechanisms underpinning this change in pattern remain unknown. In this work, we constructed an age-stratified mechanistic model to explicitly test three factors that could lead to the change in RSV transmission dynamics: 1) birth rates, 2) temperatures, and 3) viral interference. By fitting the model to weekly RSV admission data over a 20-year period and comparing different models, we found that viral interference from influenza was the only mechanism that explained the shifted biennial pattern. Our work demonstrates the complex interplay between different respiratory viruses, providing evidence that supports the presence of interactions between the H1N1 pandemic influenza virus and RSV at the population level, with implications for future public health interventions.

Epidemiology of respiratory syncytial virus in Central Queensland, Australia.

Respiratory syncytial virus (RSV) is the leading cause of bronchiolitis and pneumonia in infants. Little is known about the epidemiology, burden, and seasonality of RSV in subtropical regions of Australia like Central Queensland. This information is important to plan prevention strategies, including therapeutics, future vaccines, and health system preparedness. We collected data on laboratory-confirmed RSV cases and admissions in Central Queensland for the period 1 July 2021 to 31 December 2022. From July 2021, RSV was listed as a nationally notifiable condition on laboratory-confirmed diagnosis. During the study period, 1,142 laboratory-confirmed cases of RSV (50.0% female sex) were reported, with 169 cases (14.8%) requiring hospital admission, 12 of which (7.1%) required intensive care unit/high dependency unit admissions; two deaths occurred. Of cases requiring hospital admission, RSV was listed as the primary diagnosis in 113/169 cases (66.9%); 63/169 admitted cases (37.3%) had a major comorbidity. Of all cases, 55.4% were in children < 5 years of age (20.9% hospitalised); 35.7% in children < 2 years of age (24.3% hospitalised), and 19.1% in children < 12 months of age (27.5% hospitalised). Children under five years of age made up 78.1% of admissions, a rate of 9.0 admissions per 1,000 children over the 18-month study period, with an average age of 15.8 months (standard deviation, SD: 13.1 months) in this cohort. Indigenous children aged < 5 years were over-represented in cases (rate ratio, RR: 1.6; 95% confidence interval [95% CI]: 1.3-1.9) and admissions (RR: 1.6; 95% CI: 1.0-2.4). Antibiotics were prescribed to 48.5% of admitted cases under two years of age, despite documented bacterial infection in only 26.3% of these cases; antibiotic prescription was significantly higher in those who received a chest X-ray (p < 0.001). Of all cases, 33.5% occurred in July 2022 alone, with greater than 75.0% of cases occurring during June-August 2022. RSV showed year-round activity with a distinctive winter peak in 2022; however, this season was likely affected by coronavirus disease 2019 (COVID-19) restrictions and behaviours. Ongoing surveillance is required to better understand the epidemiology and seasonality of RSV in Central Queensland.

Evolving Epidemiology of Pediatric Respiratory Syncytial Virus (RSV) Cases Around COVID-19 Pandemic: Impact and Clinical Insights, Retrospective Cohort Study

BackgroundThe burden of respiratory syncytial virus (RSV) in high-risk pediatric patients remains unclear. Therefore, this study aims to characterize pediatric RSV cases from January 2019 to December 2022 and assess the impact of the COVID-19 pandemic on RSV burden and RSV-related outcomes. In addition, examining factors influencing RSV-related hospitalization.MethodsThis is a retrospective study that included pediatric patients (aged 14 and below) who presented at King Faisal Specialist Hospital and Research Centre (KFSHRC) in Riyadh, Saudi Arabia with RSV infection identified using real-time reverse-transcriptase polymerase chain reaction assays. Statistical analyses were performed using STATA.ResultsA total of 885 RSV cases were reported; (56.05%) were males and (43.95%) were females with a median age of 24 months [interquartile range (IQR): 11–60]. 534 (60.34%) required hospitalization. As for RSV seasonality, there was a significant increase in RSV prevalence following the COVID-19 pandemic, escalating from 205 cases in 2019 to 425 cases in 2022. The increase in 2022 was evident in January and persisted from September to December, reaching its peak during the months of October (20.70% − 88 cases) and November (32.00% − 136 cases). About (27.12%) of RSV infected children were medically free patients. Symptomatic patients exhibited various clinical manifestations, with ventilation necessary in (13.11%) of cases. Further analysis revealed significant changes in RSV-related outcomes post-COVID-19, including a decrease in hospitalization rates, an increase in medically free patients, and a lower need for ventilation (p < 0.05). Notably, a significant proportion of RSV admissions occurred within the first 6 months of life, with (77.69%) in the age group of 0 to 5 months. In addition, previous RSV infection, prematurity, low birth weight, renal disease, congenital heart disease, endocrine/metabolic disease, neuro/neuromuscular diseases, and genetic disorders were positively associated with hospitalization (P < 0.05). Interestingly, asthma and bone marrow transplantation were negatively associated with hospitalization (P < 0.05). The mortality rate in this study is (2.37%) (21/885).ConclusionThis study provides a comprehensive understanding of the demographic and clinical factors influencing RSV outcomes, highlighting the impact of the COVID-19 pandemic and shedding light on potential risk factors for RSV-related hospitalization. The highest prevalence of RSV during (September to January), aligning with global patterns and emphasizing the importance of timing in preventive strategies.

Resurgence of Respiratory Syncytial Virus in the Summer of 2021 in Denmark-a Large out-of-season Epidemic Affecting Older Children.

When coronavirus disease 2019 (COVID-19) restrictions were lifted in Denmark in the spring of 2021, a surge in respiratory syncytial virus (RSV) cases followed, causing a large out-of-season epidemic. This study aims to investigate the summer epidemic compared with 3 typical pre-COVID-19 RSV winter seasons using Danish registers to identify RSV cases, RSV-related admissions, and use of intensive care treatment. Incidence rates (IR) per 1000 person-years for RSV cases, RSV-related admissions, and intensive care treatment were calculated with 95% confidence interval (CI) for each season, stratified by age groups and incidence rate ratios (IRR) with 95% CI were calculated to compare the summer epidemic with the winter season for 2019-2020. In the summer epidemic, the IR of RSV cases and admissions exceeded previous winter seasons for all age groups. The highest increases in IRs were seen among children aged 2 to 3 years and 4 to 5 years. The IRR of cases were 4.6 (95% CI, 4.1-5.2) and 3.3 (2.6-4.2) and the IRR of admissions were 3.3 (2.7-4.2) and 3.8 (2.3-6.5) in the 2 age groups, respectively, when compared with the winter season 2019-2020. Likely because of immunity debt following COVID-19 restrictions, the summer epidemic was significantly larger than previous winter seasons, most markedly among children aged 2 to 3 and 4 to 5 years but had a similar disease severity spectrum.

1743. Health Care Resource Utilisation (HCRU) Due to Respiratory Syncytial Virus (RSV) Before the Age of Two in England

Abstract Background RSV is responsible for 33 million lower respiratory tract infections (LRTI) worldwide. The highest burden occurs in infants &amp;lt; 1 year of age during RSV season, which is from October to February in England. Due to lack of routine laboratory testing, its true disease burden is unknown. This study aimed to estimate the respiratory related primary and secondary care healthcare resource utilisation (HCRU) of RSV admissions before the age two in England. Methods This retrospective cohort study used Clinical Practice Research Datalink (CPRD)-Hospital Episode Statistics (HES) linked data to establish a birth cohort of all infants born between 01/03/2015 and 28/02/2017 (n=449,591). Case cohorts included infants under two with a hospital admission of: 1) confirmed RSV (n=4,813), 2) bronchiolitis (n=22,913), 3) any RTI (n=56,871). Each case cohort was compared with all birth cohort infants without the corresponding admission (comparative cohorts). Respiratory related HCRU (primary care, outpatient, accident and emergency [A&amp;E], and inpatient admissions) were estimated in the month prior to and up to 24 months following the first admission in each cohort. Results The RSV-coded cohort had the highest HCRU overall, mean (SD) of 5.1 (4.8) admissions vs. 1.5 (2.4) in its comparative cohort (71% difference). This difference was largely due to A&amp;E and inpatient admissions. Comparable results were found for bronchiolitis-coded and RTI-coded cohorts. The highest rates of inpatient admissions were observed for the RSV-coded case cohort, and these occurred during the calendar months of November and December. Inpatient admissions were largely among infants up to 12 months of age and included infants that were born both before and during the season (Figure 1). Conclusion Infants with an RSV admission had higher HCRU than infants without. Most hospitalisations occurred in November and December when services are at their most stretched. During the first year of life, the HCRU rates observed for infants born before and in the season were equally very high, emphasizing the need for preventative strategies to all infants entering their first RSV season. Funding: This research was funded by collaborative agreement with Sanofi / AstraZeneca and is part of the RODEO research program for RSV disease. Disclosures Maria João Fonseca, n/a, Sanofi: Advisor/Consultant Mathieu Bangert, PhD, Sanofi: Staff member Rolf Kramer, n/a, Sanofi: Stocks/Bonds Richard Hudson, n/a, Sanofi: I am an employee of Sanofi|Sanofi: Stocks/Bonds

Respiratory syncytial virus outbreak during the COVID-19 pandemic. How has it changed?

IntroductionThe epidemiology of respiratory syncytial virus (RSV) infection has changed during the COVID-19 pandemic. Our objectives were to describe the RSV epidemic in 2021 and compare it with the previous years to the pandemic. MethodsRetrospective study performed in Madrid (Spain) in a large pediatric hospital comparing the epidemiology and clinical data of RSV admissions during 2021 and the two previous seasons. Results899 children were admitted for RSV infection during the study period. During 2021, the outbreak peaked in June and the last cases were identified in July. Previous seasons were detected in autumn-winter. The number of admissions in 2021 was significantly lower than in previous seasons. There were no differences between seasons regarding age, sex or disease severity. ConclusionRSV hospitalizations during 2021 in Spain moved to summer with no cases in autumn and winter 2020–2021. Unlike other countries, clinical data were similar between epidemics.

RSV causes more severe respiratory illness than influenza in admitted children under 2‐years‐old

Both respiratory syncytial virus (RSV) and influenza-associated lower respiratory tract infections (LRTI) cause serious respiratory infections in infants and toddlers. We aimed to assess the frequency of complex hospital courses among patients admitted with influenza versus RSV LRTI. A retrospective cohort study was performed on admissions of children <2 years who were admitted for LRTI and tested positive for influenza or RSV from 2016 to 2019. The primary outcome, complex hospital course, was a composite including: intensive care unit admission, respiratory support, nasogastric tube feeds, prolonged length of stay, and death. Secondary outcomes included 7-day readmission and time to respiratory support. Differences between RSV and influenza groups were assessed and unadjusted and adjusted regression models and competing risks time to event models were developed. There were 1094 (89%) RSV admissions and 134 (11%) influenza admissions. Children admitted for influenza were significantly older (336 vs. 165 days, p < 0.001), more likely to present with an abnormal heart rate for age (84.3% vs. 73.5%, p < 0.01) and a fever (27.6% vs. 18.9%, p = 0.02). Admissions with RSV were significantly more likely to experience a complex hospital course (ORadj = 3.5, 95% CI: 2.2-5.6). In time to event analysis, RSV admissions had a significantly higher rate of respiratory support (HRadj = 3.2, 95% CI: 2.0, 5.2). Readmission rates were similar. RSV admissions were associated with a higher risk for a complex hospital course and required higher rates of respiratory support than influenza admissions. This information may help in evaluating hospital resources and admissions.

An atypical surge in RSV infections among children in Saitama, Japan in 2021

BackgroundIn 2021, atypical seasonal respiratory syncytial virus (RSV) outbreaks were observed in several countries. However, the peak, duration, and severity of these outbreaks have not been assessed. MethodsData were collected from almost all facilities with pediatric wards in Saitama Prefecture, Japan. Variables included the weekly number of patients admitted with RSV infection, their age, and the number of patients who required intubation. The average weekly admission rates (number of patients admitted divided by the number of hospitals) were compared by pre-pandemic year (2018 and 2019) and 2021, using analysis of variance. ResultsIn 2021, 1354 patients were admitted with RSV infection. The median age of the patients was < 12 months. The admission rate peaked around week 30. The slope of the peak in 2021 was markedly steeper than in the previous years. The mean weekly admission rate did not differ significantly between 2018, 2019, and 2021 (p = 0.77). The proportions of intubated patients did not differ significantly over the 4 years (2018­2021, p = 0.68). ConclusionThe overall number of RSV admissions and intubation rate in 2021 were similar to those in pre-pandemic years.

Drivers of respiratory syncytial virus seasonal epidemics in children under 5 years in Kilifi, coastal Kenya.

Respiratory syncytial virus (RSV) causes significant childhood morbidity and mortality in the developing world. The determinants of RSV seasonality are of importance in designing interventions. They are poorly understood in tropical and sub-tropical regions in low- and middle-income countries. Our study utilized long-term surveillance data on cases of RSV associated with severe or very severe pneumonia in children aged 1 day to 59 months admitted to the Kilifi County Hospital. A generalized additive model was used to investigate the association between RSV admissions and meteorological variables (maximum temperature, rainfall, absolute humidity); weekly number of births within the catchment population; and school term dates. Furthermore, a time-series-susceptible-infected-recovered (TSIR) model was used to reconstruct an empirical transmission rate which was used as a dependent variable in linear regression and generalized additive models with meteorological variables and school term dates. Maximum temperature, absolute humidity, and weekly number of births were significantly associated with RSV activity in the generalized additive model. Results from the TSIR model indicated that maximum temperature and absolute humidity were significant factors. Rainfall and school term did not yield significant relationships. Our study indicates that meteorological parameters and weekly number of births potentially play a role in the RSV seasonality in this region. More research is required to explore the underlying mechanisms underpinning the observed relationships.

Developing a prediction model to estimate the true burden of respiratory syncytial virus (RSV) in hospitalised children in Western Australia

Respiratory syncytial virus (RSV) is a leading cause of childhood morbidity, however there is no systematic testing in children hospitalised with respiratory symptoms. Therefore, current RSV incidence likely underestimates the true burden. We used probabilistically linked perinatal, hospital, and laboratory records of 321,825 children born in Western Australia (WA), 2000–2012. We generated a predictive model for RSV positivity in hospitalised children aged < 5 years. We applied the model to all hospitalisations in our population-based cohort to determine the true RSV incidence, and under-ascertainment fraction. The model’s predictive performance was determined using cross-validated area under the receiver operating characteristic (AUROC) curve. From 321,825 hospitalisations, 37,784 were tested for RSV (22.8% positive). Predictors of RSV positivity included younger admission age, male sex, non-Aboriginal ethnicity, a diagnosis of bronchiolitis and longer hospital stay. Our model showed good predictive accuracy (AUROC: 0.87). The respective sensitivity, specificity, positive predictive value and negative predictive values were 58.4%, 92.2%, 68.6% and 88.3%. The predicted incidence rates of hospitalised RSV for children aged < 3 months was 43.7/1000 child-years (95% CI 42.1–45.4) compared with 31.7/1000 child-years (95% CI 30.3–33.1) from laboratory-confirmed RSV admissions. Findings from our study suggest that the true burden of RSV may be 30–57% higher than current estimates.

Respiratory syncytial virus outbreak during the COVID-19 pandemic. How has it changed?

IntroductionThe epidemiology of respiratory syncytial virus (RSV) infection has changed during the COVID-19 pandemic. Our objectives were to describe the RSV epidemic in 2021 and compare it with the previous years to the pandemic. MethodsRetrospective study performed in Madrid (Spain) in a large pediatric hospital comparing the epidemiology and clinical data of RSV admissions during 2021 and the two previous seasons. Results899 children were admitted for RSV infection during the study period. During 2021, the outbreak peaked in June and the last cases were identified in July. Previous seasons were detected in autumn-winter. The number of admissions in 2021 was significantly lower than in previous seasons. There were no differences between seasons regarding age, sex or disease severity. ConclusionRSV hospitalizations during 2021 in Spain moved to summer with no cases in autumn and winter 2020–2021. Unlike other countries, clinical data were similar between epidemics.

Human Metapneumovirus Infection in a Children’s Hospital – It Should Get More Attention

Respiratory syncytial virus (RSV) and influenza infections are a major cause of hospitalization and intensive care unit (ICU) admission to children's hospitals and are closely tracked. We compared data over 6 seasons of human metapneumovirus (hMPV), RSV and influenza infections. During the 2014-2019 winter viral seasons, hMPV, RSV and influenza infections were tracked. For hMPV admissions, rates of hospitalizations, ICU admissions, hospital-acquired infections (HAIs) and mortalities were assessed and compared with RSV and influenza admissions. Retrospective data was used to study patients infected with hMPV. During the winter seasons of 2014-2019, the rates of hospitalization due to hMPV were significantly higher than both RSV and influenza. ICU admissions, deaths and HAIs for hMPV were similar to RSV and influenza.Of the 471 total cases with hMPV, 58 (12.3%) had chronic lung disease (CLD) and 23 (4.9%) were tracheostomy dependent. Among 104 hMPV ICU admissions from 2013 to 2019, 86 (82%) had an underlying medical diagnosis, 30 (29%) had CLD, 21 (20%) had tracheostomies and 33 (32%) required mechanical ventilation. The average age of hMPV infected children in our ICU is 3 years and 10 months. Our large descriptive study of hMPV infected children over 6 seasons showed higher rates of hospitalization compared with RSV and influenza, similar ICU and HAI rates, and deaths. ICU admitted children often had associated co-morbidities, including CLD. Further studies for focused disease surveillance and potential vaccine development for high-risk children are needed.

The Changing Epidemiology of Respiratory Viruses in Children During the COVID-19 Pandemic: A Canary in a COVID Time.

The Changing Epidemiology of Respiratory Viruses in Children During the COVID-19 Pandemic: A Canary in a COVID Time.

Time-Varying Association Between Severe Respiratory Syncytial Virus Infections and Subsequent Severe Asthma and Wheeze and Influences of Age at the Infection

Early-life severe respiratory syncytial virus (RSV) infection has been associated with subsequent risk of asthma and recurrent wheeze. However, changes in the association over time and the interaction effect of the age at first RSV infection are less well understood. We aimed to assess the time-varying association between RSV and subsequent asthma and wheeze admission and explore how the association was affected by the age at RSV infection. We retrospectively followed up a cohort of 23 365 children for a median of 6.9 years using Scottish health databases. Children who were born between 2001 and 2013 and had RSV-associated respiratory tract infection (RTI) admissions under 2 years were in the exposed group; those with unintentional accident admissions under 2 years comprised the control group. The Cox proportional-hazards model was used to report adjusted hazard ratios (HRs) of RSV admissions on subsequent asthma and wheeze admissions. We did subgroup analyses by follow-up years. We also explored how this association was affected by the age at first RSV admission. The association was strongest in the first 2 years of follow-up and decreased over time. The association persisted for 6 years in children whose first RSV-RTI admission occurred at 6-23 months of age, with an adjusted HR of 3.9 (95% confidence interval [CI], 3.1-4.9) for the first 2 years, 2.3 (95% CI, 1.6-3.2) for 2 to <4 years, and 1.9 (95% CI, 1.2-2.9) for 4 to <6 years of follow-up. In contrast, the association was only significant for the first 2 years after first RSV-RTI admissions occurring at 0-5 months. We found a more persistent association for subsequent asthma and wheeze in children whose first severe RSV infection occurred at 6-23 months compared to those whose first severe RSV infection occurred at 0-6 months. This provides new evidence for further assessment of the association and RSV intervention programs.

Hospital utilization rates for influenza and RSV: a novel approach and critical assessment

BackgroundInfluenza and respiratory syncytial virus (RSV) contribute significantly to the burden of acute lower respiratory infection (ALRI) inpatient care, but heterogeneous coding practices and availability of inpatient data make it difficult to estimate global hospital utilization for either disease based on coded diagnoses alone.MethodsThis study estimates rates of influenza and RSV hospitalization by calculating the proportion of ALRI due to influenza and RSV and applying this proportion to inpatient admissions with ALRI coded as primary diagnosis. Proportions of ALRI attributed to influenza and RSV were extracted from a meta-analysis of 360 total sources describing inpatient hospital admissions which were input to a Bayesian mixed effects model over age with random effects over location. Results of this model were applied to inpatient admission datasets for 44 countries to produce rates of hospital utilization for influenza and RSV respectively, and rates were compared to raw coded admissions for each disease.ResultsFor most age groups, these methods estimated a higher national admission rate than the rate of directly coded influenza or RSV admissions in the same inpatient sources. In many inpatient sources, International Classification of Disease (ICD) coding detail was insufficient to estimate RSV burden directly. The influenza inpatient burden estimates in older adults appear to be substantially underestimated using this method on primary diagnoses alone. Application of the mixed effects model reduced heterogeneity between countries in influenza and RSV which was biased by coding practices and between-country variation.ConclusionsThis new method presents the opportunity of estimating hospital utilization rates for influenza and RSV using a wide range of clinical databases. Estimates generally seem promising for influenza and RSV associated hospitalization, but influenza estimates from primary diagnosis seem highly underestimated among older adults. Considerable heterogeneity remains between countries in ALRI coding (i.e., primary vs non-primary cause), and in the age profile of proportion positive for influenza and RSV across studies. While this analysis is interesting because of its wide data utilization and applicability in locations without laboratory-confirmed admission data, understanding the sources of variability and data quality will be essential in future applications of these methods.

Effects of Palivizumab Guideline Changes on RSV Admissions in Patients with Congenital Heart Disease and Prematurity

Background: Respiratory syncytial virus (RSV) causes significant morbidity and mortality in patients with a history of prematurity and congenital heart disease (CHD). In 2014, the guidelines for Palivizumab became more restrictive for this population. We hypothesized the percentage of RSV+ admissions would increase overall and in this target group (TG) specifically. Methods: We conducted a retrospective review of patients under age 2 years admitted with bronchiolitis two seasons prior to the change (Pre) and two seasons after (Post). Our TG included patients who were eligible prior to the 2014 changes but currently no longer eligible. We used chi-square analysis to answer the two main hypotheses: 1) Percent RSV+/total bronchiolitis Pre vs Post and 2) Percent of TG/RSV+ Pre vs Post. Results: 1283 patients (546 pre, 737 post) were admitted with the diagnosis of RSV between 2012-2016, 866 actually tested positive for RSV (367 Pre, 499 Post). There was no significant difference in the number of total patients admitted with RSV (Pre = 67.2%, Post = 67.7%) or in our TG (Pre 7.1% vs Post 8.2%). TG overall had a more complicated course: longer length of stay, median 5 days, IQR 2 - 12 vs 3 days, IQR 1 - 5, (p , but there was no difference Pre vs Post. Conclusion: The TG had an overall higher acuity, but there was no increase in the number of patients hospitalized with RSV or severity as a result of the Palivizumab guideline changes.

1708. Impacts of age and season on rates of hospitalization for respiratory syncytial virus (RSV) in infants in the United States and their use of mechanical ventilation and charges

BackgroundRespiratory Syncytial Virus (RSV) infection is the leading cause of hospitalization in infants below age 12 months and highest below age 6 months. Despite considerable evidence on the clinical predictors of RSV hospitalizations, little is known about their cost, its drivers and their relation to age and season.MethodsWe used the National Inpatient Sample to examine RSV inpatient admissions and their average charge from 2009 to 2011. This 3-year data set includes a large, nationally representative all-payer sample of 37,376 RSV admissions of infants in the US under age 12 months recorded by month. We calculated the rate per 1000 infants of RSV hospitalizations, the share receiving mechanical ventilation (MV), and the mean charge per admission (separated by use of MV) with 95% confidence intervals by age and season, excluding incomplete data. We adjusted charges to Jan 2020 based on the medical care Consumer Price Index.ResultsThese data confirm that rates of hospitalization by age were highest for infants 1 month of chronological age (2.42 times the annualized average) and declined steadily thereafter. The percentage of hospitalizations with MV declined from months < 1 to 4, with subsequent fluctuations (Fig 1). Charges exceeded the annual average only for infants aged < 1 and 1 month (Fig 2). In 2020 prices, hospitalization charges per episode averaged $175,211 with MV vs. $17,313 without MV, totaling $1.51 billion annually for the birth cohort of 4.04 million infants ($374 per infant). As only 4.5% of hospitalizations had MV, those without MV comprised 67.5% of aggregate yearly charges. Admissions were highly seasonal, with the rate in the highest month (Feb) 341 times that in the lowest month (July). However, utilization of MV (Fig 3) tended to be lower in the RSV season but depended mostly on age. While average charges were higher outside the RSV season, their seasonal pattern was similar for admissions with and without MV.Fig. 1. Share of hospitalizations with RV (bars) vs. rate of RSV hospitalizations (line) by age Fig. 2. Charges (bars) vs. rate of RSV hospitalizations (line) by age Fig. 3. Utilization of MV (bars) vs RSV hospitalization rate (line) by seasonConclusionRSV in infants under one year generate substantial hospital charges. While each of the small share of infants receiving MV is expensive, infants with MV are not the main driver of costs (Fig 4). Rather, the large number and share (94.5%) of hospitalizations without MV is the major determinant of aggregate charges (Fig 5). Fig. 4. Relation between use of mechanical ventilation (MV) [bars] and RSV hospitalization rate [lines] by season and age (in months) Fig. 5. Hospitalization charges (bars) vs RSV hospitalization rate (line) by season DisclosuresDonald S. Shepard, PhD, Sanofi Pasteur (Grant/Research Support)

Risk of Repeated Admissions for Respiratory Syncytial Virus in a Cohort of >10 000 Hospitalized Children.

The objective was to describe respiratory syncytial virus (RSV) hospitalizations in Alberta, Canada over a 13-year period with an emphasis on the incidence and risk factors for repeat hospitalizations attributable to new RSV infections. This was a retrospective database analysis. The Alberta Health Services Discharge Abstract Database was searched for patients <5 years of age admitted to any hospital with a primary diagnosis of RSV from July 1, 2004 through June 30, 2017. Clinical characteristics were compared for children with repeat RSV admission during the same RSV season (but >30 days apart so presumably due to separate infections) compared with all other children with RSV admissions. During the study period, 10 212 children had 10 967 RSV admissions. The RSV hospitalization rate was 1.6%. A total of 666 children (6.5%) were readmitted for RSV at least once during the study period, of whom 433 (4.2%) were readmitted within 30 days of the initial hospital discharge. There were 36 children (0.35%) with 2 RSV admissions >30 days apart during the same RSV season. When compared to all other children with RSV admissions, they were more likely to have congenital heart disease or to have been diagnosed with RSV pneumonia (vs bronchiolitis or upper respiratory tract infection) during their initial hospitalization. The RSV hospitalization rate in children <5 years of age was 1.6%. Repeat RSV infections requiring readmission during the same RSV season occurred following only 0.35% of RSV hospitalizations.

Palivizumab Prophylaxis for infants 29 to 32 weeks gestation at birth: A 10-year audit from Vancouver Island using BC Guidelines.

After initially recommending palivizumab (PVZ), a monoclonal antibody against respiratory syncytial virus (RSV) for all infants 29 to 32 weeks at birth if <6 months age at season start, the American Academy of Pediatrics (AAP) and Canadian Paediatric Society (CPS) guidelines were revised. British Columbia was the only jurisdiction in North America to restrict eligibility for this group to those with additional risk factors, long before the change in national recommendations. To determine the risk for first season RSV admission for 29 to 32-week gestational age (GA) infants admitted to Victoria Neonatal Intensive Care Unit (NICU) that either received or were denied PVZ prophylaxis. Descriptive cohort study of infants eligible for prophylaxis according to earlier CPS guidelines. Instead, BC guidelines for prophylaxis were applied and data for Vancouver Island infants were collected over 10 consecutive RSV seasons. We followed 423 infants. Three hundred and thirty-six (79%) did not receive prophylaxis, of which 10 (3.0%; 95% confidence interval [CI] 1.4% to 5.4%) had an RSV hospitalization before the end of April during their first RSV season versus 3 admissions from 87 (3.5%; 95% CI 0.7% to 10%) infants who received prophylaxis. Our risk factor approach to RSV prophylaxis for infants born at 29 to 32 weeks GA resulted in a low (average incidence=3.1%) rate of RSV hospitalization. Our approach would offer considerable cost savings to RSV prophylaxis programs that continue to offer routine prophylaxis beyond 28/29 weeks GA at birth.