Community Mortality Due to Respiratory Syncytial Virus in Argentina: Population-based Surveillance Study

Cost of illness due to respiratory syncytial virus acute lower respiratory tract infection among infants hospitalized in Argentina

BACKGROUND

Information is scarce regarding the economic burden of respiratory syncytial virus (RSV) disease in low-resource settings. This study aimed to estimate the cost per episode of hospital admissions due to RSV severe disease in Argentina.

METHODS

This is a prospective cohort study that collected information regarding 256 infants under 12 months of age with acute lower respiratory tract infection (ALRTI) due to RSV in two public hospitals of Buenos Aires between 2014 and 2016. Information on healthcare resource use was collected from the patient's report and its associated costs were estimated based on the financial database and account records of the hospitals. We estimated the total cost per hospitalization due to RSV using the health system perspective. The costs were estimated in US dollars as of December 2022 (1 US dollar = 170 Argentine pesos).

RESULTS

The mean costs per RSV hospitalization in infants was US$587.79 (95% confidence interval [CI] $535.24 - $640.33). The mean costs associated with pediatric intensive care unit (PICU) admission more than doubled from those at regular pediatric wards ($1,556.81 [95% CI $512.21 - $2,601.40] versus $556.53 [95% CI $514.59 - $598.48]).

CONCLUSIONS

This study shows the direct economic impact of acute severe RSV infection on the public health system in Argentina. The estimates obtained from this study could be used to inform cost-effectiveness analyses of new preventive RSV interventions being developed.

Respiratory syncytial virus infection and novel interventions

The large global burden of respiratory syncytial virus (RSV) respiratory tract infections in young children and older adults has gained increased recognition in recent years. Recent discoveries regarding the neutralization-specific viral epitopes of the pre-fusion RSV glycoprotein have led to a shift from empirical to structure-based design of RSV therapeutics, and controlled human infection model studies have provided early-stage proof of concept for novel RSV monoclonal antibodies, vaccines and antiviral drugs. The world's first vaccines and first monoclonal antibody to prevent RSV among older adults and all infants, respectively, have recently been approved. Large-scale introduction of RSV prophylactics emphasizes the need for active surveillance to understand the global impact of these interventions over time and to timely identify viral mutants that are able to escape novel prophylactics. In this Review, we provide an overview of RSV interventions in clinical development, highlighting global disease burden, seasonality, pathogenesis, and host and viral factors related to RSV immunity.

RSV through the COVID-19 pandemic: Burden, shifting epidemiology, and implications for the future

Respiratory syncytial virus (RSV) represents a major global healthcare burden, particularly in those under 5 years of age. There is no available vaccine, with treatment limited to supportive care or palivizumab for high-risk children. Additionally, although a causal relationship has not been established, RSV has been associated with the development of asthma or wheezing in some children. The COVID-19 pandemic and the introduction of nonpharmaceutical interventions (NPIs) have caused substantial changes to RSV seasonality and epidemiology. Many countries have experienced an absence of RSV during the time of a typical season, followed by an out-of-season surge upon relaxation of NPI use. These dynamics have disrupted traditional RSV disease patterns and assumptions, but also provide a unique opportunity to learn more about the transmission of RSV and other respiratory viruses, as well as inform future approaches to RSV preventive strategies. Here, we review the RSV burden and epidemiology through the COVID-19 pandemic and discuss how new data may affect future decisions regarding RSV prevention.

Responding to Higher-Than-Expected Infant Mortality Rates from Respiratory Syncytial Virus (RSV): Improving Treatment and Reporting Strategies

Respiratory syncytial virus (RSV) has a major role in respiratory infections in young infants around the world. However, substantial progress has been made in recent years in the field of RSV. A wide variety of observational studies and clinical trials published in the past decade provide a thorough idea of the health and economic burden of RSV disease in the developing world. In this review, we discuss the impact of RSV burden of disease, major gaps in disease estimations, and challenges in generating new therapeutic options and an immune response against the virus, and briefly describe next generation technologies that are being evaluated.

Controlled Human Infection Models To Accelerate Vaccine Development

The timelines for developing vaccines against infectious diseases are lengthy, and often vaccines that reach the stage of large phase 3 field trials fail to provide the desired level of protective efficacy. The application of controlled human challenge models of infection and disease at the appropriate stages of development could accelerate development of candidate vaccines and, in fact, has done so successfully in some limited cases. Human challenge models could potentially be used to gather critical information on pathogenesis, inform strain selection for vaccines, explore cross-protective immunity, identify immune correlates of protection and mechanisms of protection induced by infection or evoked by candidate vaccines, guide decisions on appropriate trial endpoints, and evaluate vaccine efficacy. We prepared this report to motivate fellow scientists to exploit the potential capacity of controlled human challenge experiments to advance vaccine development. In this review, we considered available challenge models for 17 infectious diseases in the context of the public health importance of each disease, the diversity and pathogenesis of the causative organisms, the vaccine candidates under development, and each model's capacity to evaluate them and identify correlates of protective immunity. Our broad assessment indicated that human challenge models have not yet reached their full potential to support the development of vaccines against infectious diseases. On the basis of our review, however, we believe that describing an ideal challenge model is possible, as is further developing existing and future challenge models.

Aetiology of childhood pneumonia in low- and middle-income countries in the era of vaccination: a systematic review

Background

This systematic review aimed to describe common aetiologies of severe and non-severe community acquired pneumonia among children aged 1 month to 9 years in low- and middle-income countries.

Methods

We searched the MEDLINE, EMBASE, and PubMed online databases for studies published from January 2010 to August 30, 2020. We included studies on acute community-acquired pneumonia or acute lower respiratory tract infection with ≥1 year of continuous data collection; clear consistent case definition for pneumonia; >1 specimen type (except empyema studies where only pleural fluid was required); testing for >1 pathogen including both viruses and bacteria. Two researchers reviewed the studies independently. Results were presented as a narrative summary. Quality of evidence was assessed with the Quality Assessment Tool for Quantitative Studies. The study was registered on PROSPERO [CRD42020206830].

Results

We screened 5184 records; 1305 duplicates were removed. The remaining 3879 titles and abstracts were screened. Of these, 557 articles were identified for full-text review, and 55 met the inclusion criteria - 10 case-control studies, three post-mortem studies, 11 surveillance studies, eight cohort studies, five cross-sectional studies, 12 studies with another design and six studies that included patients with pleural effusions or empyema. Studies which described disease by severity showed higher bacterial detection (Streptococcus pneumoniae, Staphylococcus aureus) in severe vs non-severe cases. The most common virus causing severe disease was respiratory syncytial virus (RSV). Pathogens varied by age, with RSV and adenovirus more common in younger children. Influenza and atypical bacteria were more common in children 5-14 years than younger children. Malnourished and HIV-infected children had higher rates of pneumonia due to bacteria or tuberculosis.

Conclusions

Several viral and bacterial pathogens were identified as important targets for prevention and treatment. Bacterial pathogens remain an important cause of moderate to severe disease, particularly in children with comorbidities despite widespread PCV and Hib vaccination.

Global, regional, and national disease burden estimates of acute lower respiratory infections due to respiratory syncytial virus in children younger than 5 years in 2019: a systematic analysis

BACKGROUND

Respiratory syncytial virus (RSV) is the most common cause of acute lower respiratory infection in young children. We previously estimated that in 2015, 33·1 million episodes of RSV-associated acute lower respiratory infection occurred in children aged 0-60 months, resulting in a total of 118 200 deaths worldwide. Since then, several community surveillance studies have been done to obtain a more precise estimation of RSV associated community deaths. We aimed to update RSV-associated acute lower respiratory infection morbidity and mortality at global, regional, and national levels in children aged 0-60 months for 2019, with focus on overall mortality and narrower infant age groups that are targeted by RSV prophylactics in development.

METHODS

In this systematic analysis, we expanded our global RSV disease burden dataset by obtaining new data from an updated search for papers published between Jan 1, 2017, and Dec 31, 2020, from MEDLINE, Embase, Global Health, CINAHL, Web of Science, LILACS, OpenGrey, CNKI, Wanfang, and ChongqingVIP. We also included unpublished data from RSV GEN collaborators. Eligible studies reported data for children aged 0-60 months with RSV as primary infection with acute lower respiratory infection in community settings, or acute lower respiratory infection necessitating hospital admission; reported data for at least 12 consecutive months, except for in-hospital case fatality ratio (CFR) or for where RSV seasonality is well-defined; and reported incidence rate, hospital admission rate, RSV positive proportion in acute lower respiratory infection hospital admission, or in-hospital CFR. Studies were excluded if case definition was not clearly defined or not consistently applied, RSV infection was not laboratory confirmed or based on serology alone, or if the report included fewer than 50 cases of acute lower respiratory infection. We applied a generalised linear mixed-effects model (GLMM) to estimate RSV-associated acute lower respiratory infection incidence, hospital admission, and in-hospital mortality both globally and regionally (by country development status and by World Bank Income Classification) in 2019. We estimated country-level RSV-associated acute lower respiratory infection incidence through a risk-factor based model. We developed new models (through GLMM) that incorporated the latest RSV community mortality data for estimating overall RSV mortality. This review was registered in PROSPERO (CRD42021252400).

FINDINGS

In addition to 317 studies included in our previous review, we identified and included 113 new eligible studies and unpublished data from 51 studies, for a total of 481 studies. We estimated that globally in 2019, there were 33·0 million RSV-associated acute lower respiratory infection episodes (uncertainty range [UR] 25·4-44·6 million), 3·6 million RSV-associated acute lower respiratory infection hospital admissions (2·9-4·6 million), 26 300 RSV-associated acute lower respiratory infection in-hospital deaths (15 100-49 100), and 101 400 RSV-attributable overall deaths (84 500-125 200) in children aged 0-60 months. In infants aged 0-6 months, we estimated that there were 6·6 million RSV-associated acute lower respiratory infection episodes (4·6-9·7 million), 1·4 million RSV-associated acute lower respiratory infection hospital admissions (1·0-2·0 million), 13 300 RSV-associated acute lower respiratory infection in-hospital deaths (6800-28 100), and 45 700 RSV-attributable overall deaths (38 400-55 900). 2·0% of deaths in children aged 0-60 months (UR 1·6-2·4) and 3·6% of deaths in children aged 28 days to 6 months (3·0-4·4) were attributable to RSV. More than 95% of RSV-associated acute lower respiratory infection episodes and more than 97% of RSV-attributable deaths across all age bands were in low-income and middle-income countries (LMICs).

INTERPRETATION

RSV contributes substantially to morbidity and mortality burden globally in children aged 0-60 months, especially during the first 6 months of life and in LMICs. We highlight the striking overall mortality burden of RSV disease worldwide, with one in every 50 deaths in children aged 0-60 months and one in every 28 deaths in children aged 28 days to 6 months attributable to RSV. For every RSV-associated acute lower respiratory infection in-hospital death, we estimate approximately three more deaths attributable to RSV in the community. RSV passive immunisation programmes targeting protection during the first 6 months of life could have a substantial effect on reducing RSV disease burden, although more data are needed to understand the implications of the potential age-shifts in peak RSV burden to older age when these are implemented.

FUNDING

EU Innovative Medicines Initiative Respiratory Syncytial Virus Consortium in Europe (RESCEU).

Predictors of poor outcomes of respiratory syncytial virus acute lower respiratory infections in children under 5 years of age in a middle-income tropical country based on the National Public Health Surveillance System

OBJECTIVES

The aim of the present study is to gain insight into the identification of region-specific factors associated with poor outcomes in children under 5 years of age with confirmed respiratory syncytial virus acute lower respiratory infection (RSV-ALRI) living in Colombia, a middle-income country, based on the National Public Health Surveillance System of the country.

METHODS

An analytical cross-sectional study was conducted using epidemiological data from the records of morbidity and mortality of respiratory infections as registered in the surveillance system report of the National Institute of Health of Colombia 2018, including children under 5 years of age with confirmed RSV-ALRI. Predictor variables included demographic and clinical variables, as well as variables measured after hospital attendance. Outcome variables analyzed were respiratory failure, the need for pediatric intensive care unit admission, and mortality.

RESULTS

Of a total of 8470 patients with a diagnosis of ALRI, we selected 1215 (14.3%) that were under 5 years of age and were positive for RSV. After controlling for potential confounders, it was found that age, gender, socioeconomic stratum, incomplete pneumococcal conjugate vaccine 13 immunization for age, cardiac disease, and malnutrition as comorbidities, chest X-ray findings, and development of sepsis independently predicted poor outcomes among the patients analyzed.

CONCLUSIONS

The identified predictors for poor outcomes in RSV-affected children may be helpful for guiding efficient and targeted national and/or regional programs and public policies to assist in achieving Goal 3 of the Sustainable Development Goals adopted by the United Nations in 2015.

Mycoplasma pneumoniae and Adenovirus Coinfection Cause Pediatric Severe Community-Acquired Pneumonia

Consolidation is one complication of pediatric severe community-acquired pneumonia (SCAP) that can respond poorly to conservative medical treatment. We investigated the pathogens that cause pediatric SCAP including cases with persistent consolidation that need bronchoscopy intervention. Alveolar lavage fluid (ALF) samples collected from cases admitted to Children’s Hospital of Fudan University with SCAP during January 2019 to March in 2019 were retrospectively tested by the RespiFinder 2SMART multiplex PCR (multi-PCR) assay targeting 22 respiratory pathogens. A total of 90 cases and 91 samples were enrolled; 80.0% (72/90) of the cases had pulmonary consolidation and/or atelectasis. All samples were positive with targeted pathogens tested by multi-PCR, and 92.3% (84/91) of the samples were co-detected with pathogens. Mycoplasma pneumoniae (MP) and adenovirus (ADV) as the two dominant pathogens, with the positive rates of 96.7% (88/91) and 79.1% (72/91), respectively. Most of the samples were positive with MP and ADV simultaneously. As a control, 78.0% (71/91) of the samples were positive by conventional tests (CT), in which MP had the detection rate of 63.9% (55/86) by a traditional real-time PCR assay, while ADV were positive in 13.1% (12/91) of the samples by a direct immunofluorescence assay (DFA). In cases with persistent pulmonary consolidation, the positive rates of pathogens by multi-PCR and CT were 100% (72/72) and 81.9% (59/72), respectively. There were no significant differences of MP or ADV positive rates between cases with and without pulmonary consolidation. MP and ADV most prevalent in pediatric SCAP cases required fiberscope intervention, and presented with coinfections dominantly.

IMPORTANCE Pathogens that cause pediatric severe community-acquired pneumonia (SCAP) requiring bronchoscopy intervention are understudied. Through this study, we explore the etiology of SCAP form alveolar lavage fluid (ALF) samples by the RespiFinder 2SMART multi-PCR assay. It is observed that high mixed detection rates of Mycoplasma pneumoniae and adenovirus in ALF samples collected from hospitalized SCAP children experienced bronchoscopy intervention. Eighty percent of the cases had pulmonary consolidation and/or atelectasis. The presence of possible coinfection of these two pathogens might contribute to poor clinical anti-infection response. The results of this study might be helpful for the selection of clinical strategies for the empirical treatment of such pediatric SCAP cases.

Infant deaths from respiratory syncytial virus in Lusaka, Zambia from the ZPRIME study: a 3-year, systematic, post-mortem surveillance project

Background

Respiratory syncytial virus (RSV) is the leading cause of acute lower respiratory tract infections and a key driver of childhood mortality. Previous RSV burden of disease estimates used hospital-based surveillance data and modelled, rather than directly measured, community deaths. Given this uncertainty, we conducted a 3-year post-mortem prevalence study among young infants at a busy morgue in Lusaka, Zambia—the Zambia Pertussis RSV Infant Mortality Estimation (ZPRIME) study.

Methods

Infants were eligible for inclusion if they were aged between 4 days and less than 6 months and were enrolled within 48 h of death. Enrolment occurred mainly at the University Teaching Hospital of the University of Zambia Medical School (Lusaka, Zambia), the largest teaching hospital in Zambia. We extracted demographic and clinical data from medical charts and official death certificates, and we conducted verbal autopsies with the guardian or next of kin. RSV was identified using reverse transcriptase quantitative PCR and stratified by age, time of year, and setting (community vs facility deaths). By combining the PCR prevalence data with syndromic presentation, we estimated the proportion of all infant deaths that were due to RSV.

Findings

The ZPRIME study ran from Aug 31, 2017, to Aug 31, 2020, except for from April 1 to May 6, 2020, during which data were not collected due to restrictions on human research at this time (linked to COVID-19). We enrolled 2286 deceased infants, representing 79% of total infant deaths in Lusaka. RSV was detected in 162 (7%) of 2286 deceased infants. RSV was detected in 102 (9%) of 1176 community deaths, compared with 10 (4%) of 236 early facility deaths (<48 h from admission) and 36 (5%) of 737 late facility deaths (≥48 h from admission). RSV deaths were concentrated in infants younger than 3 months (116 [72%] of 162 infants), and were clustered in the first half of each year and in the poorest and most densely populated Lusaka townships. RSV caused at least 2·8% (95% CI 1·0–4·6) of all infant deaths and 4·7% (1·3–8·1) of community deaths.

Interpretation

RSV was a major seasonal cause of overall infant mortality, particularly among infants younger than 3 months of age. Because most RSV deaths occurred in the community and would have been missed through hospital-based surveillance, the global burden of fatal RSV has probably been underestimated.

Funding

Bill & Melinda Gates Foundation.

Uncovering Causes of Childhood Death Using the Minimally Invasive Autopsy at the Community Level in an Urban Vulnerable Setting of Argentina: A Population-Based Study

Background

Precise determination of the causal chain that leads to community deaths in children in low- and middle-income countries is critical to estimating all causes of mortality accurately and to planning preemptive strategies for targeted allocation of resources to reduce this scourge.

Methods

An active surveillance population-based study that combined minimally invasive tissue sampling (MITS) and verbal autopsies (VA) among children under 5 was conducted in Buenos Aires, Argentina, from September 2018 to December 2020 to define the burden of all causes of community deaths.

Results

Among 90 cases enrolled (86% of parental acceptance), 81 had complete MITS, 15.6% were neonates, 65.6% were post-neonatal infants, and 18.9% were children aged 1–5 years. Lung infections were the most common cause of death (CoD) in all age groups (57.8%). Among all cases of lung infections, acute bronchiolitis was the most common CoD in infants aged <12 months (23 of 36, 63.9%), and bacterial pneumonia was the most common cause in children aged >12 months (8 of 11, 72.7%). The most common comorbid condition in all age groups was undernutrition in 18 of 90 (20%). It was possible to find an immediate CoD in 78 of 81 subjects where MITS could be done. With this combined approach, we were able to determine that sudden infant death syndrome was overestimated in state reports.

Conclusions

CoD determination by a combination of MITS and VA provides an accurate estimation of the chain of events that leads to death, emphasizing possible interventions to prevent mortality in children.