Cost utility of palivizumab prophylaxis among pre-term infants in the United States: a national policy perspective

Impact of Child Respiratory Syncytial Virus-Confirmed Infections on Caregivers in Japan: A Web-Based Survey

Background/Objectives: Despite being the leading cause of acute lower respiratory tract infections in infants, the impact of respiratory syncytial virus (RSV) on the caregivers of infected children remains largely unexplored. This study is the first in Japan to examine the psychological, social, and economic burdens on caregivers of infants infected with RSV. Methods: An online questionnaire survey was used to understand the circumstances surrounding RSV infection and the psychological, social, and economic burdens on caregivers. Equal numbers of infants aged either <6 or ≥6 months were enrolled. Results: A total of 606 caregivers were included in the final analysis. Notably, 36.1% of the infants were hospitalized. Most caregivers (91.4%) felt anxious about their infants' RSV infection, and more than half (55.8%) answered that their anxiety interfered with their daily lives. Caregivers whose daily routines were disrupted due to concerns about RSV infection were more likely to hospitalize infants, particularly for extended stays. Infection significantly affected family dynamics, hindering normal daily activities and escalating stress, which in turn led to conflicts and arguments among family members (30.4%). Regarding the financial burden, most caregivers incurred medical expenses (34.2%). Additionally, 76.9% of caregivers expressed interest in the hypothetical RSV vaccination. Conclusions: In Japan, caregivers of infants with RSV experience had significant psychological burden regardless of whether the treatment is outpatient or inpatient. In addition, a non-negligible proportion of caregivers suffer from societal and economic burdens. This study lays the groundwork for all stakeholders to fully comprehend the comprehensive disease burden of child RSV infections.

Cost-utility analysis of palivizumab for preventing respiratory syncytial virus in preterm neonates and infants in Colombia

AIM

Palivizumab has proven effective in reducing hospitalizations, preventing severe illness, improving health outcomes, and reducing healthcare costs for infants at risk of respiratory syncytial virus (RSV) infection. We aim to assess the value of palivizumab in preventing RSV infection in high-risk infants in Colombia, where RSV poses a significant threat, causing severe respiratory illness and hospitalizations.

METHODS

We conducted a decision tree analysis to compare five doses of palivizumab with no palivizumab. The study considered three population groups: preterm neonates (≤ 35 weeks gestational age), infants with bronchopulmonary dysplasia (BPD), and infants with hemodynamically significant congenital heart disease (CHD). We obtained clinical efficacy data from IMpact-RSV and Cardiac Synagis trials, while we derived neonatal hospitalization risks from the SENTINEL-1 study. We based hospitalization and recurrent wheezing management costs on Colombian analyses and validated them by experts. We estimated incremental cost-effectiveness ratios and performed 1,000 Monte Carlo simulations for probabilistic sensitivity analyses.

RESULTS

Palivizumab is a dominant strategy for preventing RSV infection in preterm neonates and infants with BPD and CHD. Its high efficacy (78% in preventing RSV in preterm infants), the substantial risk of illness and hospitalization, and the high costs associated with hospitalization, particularly in neonatal intensive care settings, support this finding. The scatter plots and willingness-to-pay curves align with these results.

CONCLUSION

Palivizumab is a cost-saving strategy in Colombia, effectively preventing RSV infection in preterm neonates and infants with BPD and CHD by reducing hospitalizations and lowering healthcare costs.

Clinical Practice Patterns and Risk Factors for Severe Conditions in Pediatric Hospitalizations With Respiratory Syncytial Virus in Japan: A Nationwide Analyses (2018-2022)

BACKGROUND

Respiratory syncytial virus (RSV) represents a global health challenge, especially among younger children. While the disease burden in Japan has been preliminarily quantified, there remains a lack of comprehensive understanding regarding treatment patterns and the influence of known risk factors at a national scale.

MATERIALS AND METHODS

We conducted a retrospective cohort study consisting of 50,482 children under 5 years hospitalized with RSV infections during 2018-2022 using the Medical Data Vision database. We investigated trends in patient characteristics, health resource use, treatment patterns, and laboratory data. Additionally, multivariable modified Poisson regression models were used to investigate the risk factors associated with severe conditions.

RESULTS

We observed an increasing trend in the inpatient healthcare costs and decreasing trends in the use of antibiotics, bronchodilators, systemic corticosteroids and other symptomatic medications from 2018 to 2022. Risk factors associated with severe RSV infections were children less than 1 year (risk ratio, 2.90; 95% CI: 2.53-3.32) and the number of complex chronic diseases (risk ratio for 1 disease, 2.68; 95% CI: 2.34-3.06: risk ratio for 2 or more diseases, 6.91; 95% CI: 5.81-8.21). Annual inpatient healthcare costs for RSV infections were estimated at 11-14 billion Japanese Yen for younger children.

CONCLUSIONS

Our study observed the changes in practice patterns and health resource use for children hospitalized with RSV infections and identified risk factors associated with severe conditions. These findings provide insights for policymakers and clinicians aiming to devise strategies for further improving clinical practices, including newly developed vaccines and single-dose long-acting monoclonal antibodies.

Cost-effectiveness of nirsevimab and palivizumab for respiratory syncytial virus prophylaxis in preterm infants 29-34 6/7 weeks' gestation in the United States

BACKGROUND

Respiratory syncytial virus (RSV) hospitalizations have increased since the 2014 guideline update recommended against the use of palivizumab for preterm infants born ≥29 0/7 weeks' gestational age (GA) without additional risk factors. A novel drug candidate, nirsevimab, has been developed for this population. We analyzed the cost-effectiveness of palivizumab/nirsevimab vs. no prophylaxis in this population.

METHODS

A hybrid-Markov model predicted the RSV clinical course in the first year of life and sequelae in the subsequent four years for preterm infants from the healthcare and societal perspectives. Model parameters were derived from the literature. We calculated costs and quality-adjusted life-years (QALYs) to produce an incremental cost-effectiveness ratio (ICER) evaluated at a willingness-to-pay threshold of $150,000/QALY. Sensitivity analyses assessed model robustness. A threshold analysis examined nirsevimab pricing uncertainty.

RESULTS

Compared to no prophylaxis, palivizumab costs $9572 and $9584 more from the healthcare and societal perspectives, respectively, with 0.0019 QALYs gained per patient over five years, resulting in ICERs >$5 million per QALY from each perspective. Results were robust to parameter uncertainties; probabilistic sensitivity analysis revealed that no prophylaxis had a 100% probability of being cost-effective. The threshold analysis suggested that nirsevimab is not cost-effective when compared to no prophylaxis if the price exceeds $1962 from a societal perspective.

CONCLUSION

Palivizumab is dominated by no prophylaxis for preterm infants 29 0/7-34 6/7 weeks' GA with no additional risk factors. Relevant stakeholders should consider alternatives to palivizumab for this population that are both effective and economical.

Quality of life burden on United States infants and caregivers due to lower respiratory tract infection and adjusting for selective testing: Pilot prospective observational study

Background and Aims

Policymakers need data about the burden of respiratory syncytial virus (RSV) lower respiratory tract infections (LRTI) among infants. This study estimates quality of life (QoL) for otherwise healthy term US infants with RSV-LRTI and their caregivers, previously limited to premature and hospitalized infants, and corrects for selective testing.

Methods

The study enrolled infants <1 year with a clinically diagnosed LRTI encounter between January and May 2021. Using an established 0-100 scale, the 36 infants' and caregivers' QoL at enrollment and quality-adjusted life year losses per 1000 LRTI episodes (quality-adjusted life years [QALYs]/1000) were validated and analyzed. Regression analyses examined predictors of RSV-testing and RSV-positivity, creating modeled positives.

Results

Mean QoL at enrollment in outpatient (n = 11) LRTI-tested infants (66.4) was lower than that in not-tested LRTI infants (79.6, p = 0.096). For outpatient LRTI infants (n = 23), median QALYs/1000 losses were 9.8 and 0.25 for their caregivers. RSV-positive outpatient LRTI infants (n = 6) had significantly milder QALYs/1000 losses (7.0) than other LRTI-tested infants (n = 5)(21.8, p = 0.030). Visits earlier in the year were more likely to be RSV-positive than later visits (p = 0.023). Modeled RSV-positivity (51.9%) was lower than the observed rate (55.0%). Infants' and caregivers' QALYs/1000 loss were positively correlated (rho = 0.34, p = 0.046), indicating that infants perceived as sicker imposed greater burdens on caregivers.

Conclusions

The overall median QALYs/1000 losses for LRTI (9.0) and RSV-LRTI (5.6) in US infants are substantial, with additional losses for their caregivers (0.25 and 0.20, respectively). These losses extend equally to outpatient episodes. This study is the first reporting QALY losses for infants with LRTI born at term or presenting in nonhospitalized settings, and their caregivers.

Is immunization with palivizumab really effective in high-risk children?

AIM

The aim of this research is to determine the specific characteristics of the immunized children during a 15-year period and the readmissions to hospital due to potential infections of the respiratory tract.

MATERIAL AND METHODS

This retrospective cohort study was conducted in the period from October 2008 to March 2022. The test group consists of 222 infants who met the strict criteria for immunization.

RESULTS

The study observed 222 infants who were immunized with palivizumab during the 14-year period. 124 (55.9%) infants were preterm (< 32 weeks) and 69 (31.1%) were infants with congenital heart defects, whereas 29 (13.1%) exhibited other individual risk factors. 38 (17.1%) were re-admitted to the pulmonary ward. Upon re-admission, a quick test to diagnose for RSV infections was conducted and only one infant tested positive.

RESULTS

The conclusion of our 14-year study is that palivizumab prophylaxis has truly proven itself effective for infants at risk in our region during the research time period. Over the years, the immunization season has not changed and the number of doses hasremained the same, as have the indications for immunization. What has changed, however, is an increase in the number of immunized infants without a significant increase in the number of re-admissions to hospital on account of respiratory disorders.

Effectiveness and cost-effectiveness of RSV infant and maternal immunization programs: A case study of Nunavik, Canada

BACKGROUND

Despite passive immunization with palivizumab to select high-risk children under two years of age, the health and economic burden of respiratory syncytial virus (RSV) remains substantial. We evaluated the effectiveness and cost-effectiveness of immunization programs with new generations of RSV prophylactics, including long-acting monoclonal antibodies (LAMA) and maternal vaccines, in terms of reducing hospitalizations in Nunavik, a Canadian Arctic region.

METHODS

We developed an agent-based model of RSV transmission and parameterized it with the demographics and burden of RSV in Nunavik, Québec. We compared various immunization strategies, taking into account the costs associated with program delivery and calculating the incremental cost-effectiveness ratio (ICER) using quality-adjusted life-years (QALYs) gained as a measure of effectiveness. Scenario analyses included immunization with palivizumab and LAMA for infants under one year of age, and maternal vaccination in mild, moderate, and severe RSV seasons. Data were analysed from November 1, 2019 to May 1, 2021.

FINDINGS

We found that a Nunavik pilot program with palivizumab which included healthy full-term infants aged 0-2 months in addition to those considered high-risk for complicated RSV disease is not cost-effective, compared to offering palivizumab only to preterm/chronically ill infants under 1 year of age. Using LAMA as prophylaxis produces ICER values of CAD $39,414/QALY (95% Credible Interval [CrI]: $39,314-$40,017) in a mild season (moderately cost-effective) and CAD $5,255/QALY (95% CrI: $5,222-$5,307) in a moderate season (highly cost-effective). LAMA was a dominant (cost-saving with negative incremental costs and positive incremental effects) strategy in a severe RSV season. Maternal vaccination combined with immunization of preterm/chronically ill infants 3-11 months was also a dominant (cost-saving) strategy in all seasons.

INTERPRETATION

The switch from palivizumab in RSV immunization programs to new prophylactics would lead to significant savings, with LAMA being an effective strategy without compromising benefits in terms of reducing hospitalizations.

Emerging antibody-based products for infectious diseases: Planning for metric ton manufacturing

This review focuses on the emerging monoclonal antibody market for infectious diseases and the metric ton scale manufacturing requirements to meet global demand. Increasing access to existing antibody-based products coupled with the unmet need in infectious disease will likely exceed the current existing global manufacturing capacity. Further, the large numbers of individuals infected during epidemics such as the ongoing COVID-19 pandemic emphasizes the need to plan for metric ton manufacturing of monoclonal antibodies by expanding infrastructure and exploring alternative production systems.

Socioeconomic Impact of RSV Hospitalization

Respiratory syncytial virus (RSV) disease is a significant cause of morbidity and socioeconomic burden worldwide among young children. The majority of RSV-associated lower respiratory tract infections (LRTI) and mortality occurs in developing countries and is associated with various sociodemographic risk factors. Independent risk factors for severe RSV disease include age and premature birth. While RSV mortality in developed countries is lower relative to developing countries, high-risk infants with comorbidities experience higher rates of mortality. RSV LRTI is often severe and is associated with hospitalization, increased need for intensive care unit admission and mechanical ventilation, long-term complications, and caregiver stress and loss of work productivity. Overall, these factors translate to higher health care resource utilization and costs and should be factored into the consideration for RSV prophylaxis. Multiple vaccine candidates and long-acting monoclonal antibodies are in various stages of clinical development. Currently, palivizumab is the only approved RSV immunoprophylaxis available for use in specific high-risk pediatric populations. This review will discuss the socioeconomic impact and health care resource utilization of RSV-related hospitalization (RSVH) as well as various sociodemographic risk factors that can be used to identify children at high risk of developing severe RSV disease.

Antiviral Drug Targets of Single-Stranded RNA Viruses Causing Chronic Human Diseases

Ribonucleic acid (RNA) viruses associated with chronic diseases in humans are major threats to public health causing high mortality globally. The high mutation rate of RNA viruses helps them to escape the immune response and also is responsible for the development of drug resistance. Chronic infections caused by human immunodeficiency virus (HIV) and hepatitis viruses (HBV and HCV) lead to acquired immunodeficiency syndrome (AIDS) and hepatocellular carcinoma respectively, which are one of the major causes of human deaths. Effective preventative measures to limit chronic and re-emerging viral infections are absolutely necessary. Each class of antiviral agents targets a specific stage in the viral life cycle and inhibits them from its development and proliferation. Most often, antiviral drugs target a specific viral protein, therefore only a few broad-spectrum drugs are available. This review will be focused on the selected viral target proteins of pathogenic viruses containing single-stranded (ss) RNA genome that causes chronic infections in humans (e.g. HIV, HCV, Flaviviruses). In the recent past, an exponential increase in the number of available three-dimensional protein structures (>150000 in Protein Data Bank), allowed us to better understand the molecular mechanism of action of protein targets and antivirals. Advancements in the in silico approaches paved the way to design and develop several novels, highly specific small-molecule inhibitors targeting the viral proteins.

Cost-analysis of Withdrawing Immunoprophylaxis for Respiratory Syncytial Virus in Infants Born at 33-35 Weeks Gestational Age in Quebec: A Multicenter Retrospective Study

BACKGROUND

In 2015, the Quebec Ministry of Health limited palivizumab prophylaxis for respiratory syncytial virus (RSV) in premature infants to those born at <33 weeks gestational age (wGA), unless other indications were present. We compared RSV-related costs for 2 seasons before the change (2013-2014, 2014-2015) and 2 seasons after (2015-2016, 2016-2017) in premature infants 33-35 wGA.

METHODS

Using payer and societal perspectives, costs associated with hospitalizations for RSV and lower respiratory tract infection (LRTI) in infants born at 33-35 wGA were estimated. Inputs were from a 2013-2017 retrospective cohort study in 25 Quebec hospitals of RSV/LRTI hospitalizations among infants <6 months old at the start of, or born during, the RSV season. Resource utilization data (hospital stay, procedures, visits, transportation, out-of-pocket expenses and work productivity) were collected from charts and parent interviews allowing estimation of direct and indirect costs. Costs, including palivizumab administration, were derived from provincial sources and adjusted to 2018 Canadian dollars. Costs were modeled for preterm infants hospitalized for RSV/LRTI pre- and postrevision of guidelines and with matched term infants hospitalized for RSV/LRTI during 2015-2017 (comparator).

RESULTS

Average total direct and indirect costs for 33-35 wGA infants were higher postrevision of guidelines ($29,208/patient, 2015-2017; n = 130) compared with prerevision ($16,976/patient, 2013-2015; n = 105). Total costs were higher in preterm infants compared with term infants (n = 234) postrevision of guidelines ($29,208/patient vs. $10,291/patient).

CONCLUSIONS

Immunoprophylaxis for RSV in infants born at 33-35 wGA held a cost advantage for hospitalizations due to RSV/LRTI.

Direct medical costs of RSV-related bronchiolitis hospitalizations in a middle-income tropical country

INTRODUCTION AND OBJECTIVES

With the objective of making informed decisions on resource allocation, there is a critical need for studies that provide accurate information on hospital costs for treating respiratory syncytial virus (RSV)-related bronchiolitis, mainly in middle-income countries (MICs). The aim of the present study was to evaluate the direct medical costs associated with bronchiolitis hospitalizations caused by infection with RSV in Bogota, Colombia.

MATERIAL AND METHODS

We reviewed the available electronic medical records (EMRs) for all infants younger than two years of age who were admitted to the Fundacion Hospital de La Misericordia with a discharge principal diagnosis of RSV-related bronchiolitis over a 24-month period from January 2016 to December 2017. Direct medical costs of RSV-related bronchiolitis were retrospectively collected by dividing the infants into three groups: those requiring admission to the pediatric ward (PW) only, those requiring admission to the pediatric intermediate care unit (PIMC), and those requiring to the pediatric intensive care unit (PICU).

RESULTS

A total of 89 patients with a median (IQR) age of 7.1 (3.1-12.2) months were analyzed of whom 20 (56.2%) were males. Overall, the median (IQR) cost of infants treated in the PW, in the PIMC, and in the PICU was US$518.0 (217.0-768.9) vs. 1305.2 (1051.4-1492.2) vs. 2749.7 (1372.7-4159.9), respectively, with this difference being statistically significant (p<0.001).

CONCLUSIONS

The present study helps to further our understanding of the economic burden of RSV-related bronchiolitis hospitalizations among infants of under two years of age in a middle-income tropical country.

Cost-effectiveness of Palivizumab for Respiratory Syncytial Virus: A Systematic Review

CONTEXT

Palivizumab prophylaxis is used as passive immunization for respiratory syncytial virus (RSV). However, because of its high cost, the value of this intervention is unclear.

OBJECTIVE

To systematically review the cost-effectiveness of palivizumab prophylaxis compared with no prophylaxis in infants <24 months of age.

DATA SOURCES

Medline, Embase, and Cochrane Library up to August 2018.

STUDY SELECTION

Two reviewers independently screened results to include economic evaluations conducted between 2000 and 2018 from Organization for Economic Cooperation and Development countries.

DATA EXTRACTION

Two reviewers independently extracted outcomes. Quality appraisal was completed by using the Joanna Briggs Institute checklist. Costs were adjusted to 2017 US dollars.

RESULTS

We identified 28 economic evaluations (20 cost-utility analyses and 8 cost-effectiveness analyses); most were from the United States (n = 6) and Canada (n = 5). Study quality was high; 23 studies met >80% of the Joanna Briggs Institute criteria. Palivizumab prophylaxis ranged from a dominant strategy to having an incremental cost-effectiveness ratio of $2 526 203 per quality-adjusted life-year (QALY) depending on study perspective and targeted population. From the payer perspective, the incremental cost-effectiveness ratio for preterm infants (29-35 weeks' gestational age) was between $5188 and $791 265 per QALY, with 90% of estimates <$50 000 per QALY. Influential parameters were RSV hospitalization reduction rates, palivizumab cost, and discount rate.

LIMITATIONS

Model design heterogeneity, model parameters, and study settings were barriers to definitive conclusions on palivizumab's economic value.

CONCLUSIONS

Palivizumab as RSV prophylaxis was considered cost-effective in prematurely born infants, infants with lung complications, and infants from remote communities.

Should we use Palivizumab immunoprophylaxis for infants against respiratory syncytial virus? - a cost-utility analysis

BACKGROUND

Passive immunization against RSV (Respiratory Syncytial Virus) is given in most western countries (including Israel) to infants of high risk groups such as premature babies, and infants with Congenital Heart Disease or Congenital Lung Disease. However, immunoprophylaxis costs are extremely high ($2800-$4200 per infant). Using cost-utility analysis criteria, we evaluate whether it is justified to expand, continue or restrict nationwide immunoprophylaxis using palivizumab of high risk infants against RSV.

METHODS

Epidemiological, demographic, health service utilisation and economic data were integrated from primary (National Hospitalization Data, etc.) and secondary data sources (ie: from published articles) into a spread-sheet to calculate the cost per averted disability-adjusted life year (DALY) of vaccinating various infant risk groups. Costs of intervention included antibody plus administration costs. Treatment savings and DALYs averted were estimated from applying vaccine efficacy data to relative risks of being hospitalised and treated for RSV, including possible long-term sequelae like asthma and wheezing.

RESULTS

For all the groups RSV immunoprophylaxis is clearly not cost effective as its cost per averted DALY exceeds the $105,986 guideline representing thrice the per capita Gross Domestic Product. Vaccine price would have to fall by 48.1% in order to justify vaccinating Congenital Heart Disease or Congenital Lung Disease risk groups respectively on pure cost-effectiveness grounds. For premature babies of < 29 weeks, 29-32 and 33-36 weeks gestation, decreases of 36.8%, 54.5% and 83.3% respectively in vaccine price are required.

CONCLUSIONS

Based solely on cost-utility analysis, at current price levels it is difficult to justify the current indications for passive vaccination with Palivizumab against RSV. However, if the manufacturers would reduce the price by 54.5% then it would be cost-effective to vaccinate the Congenital Heart Disease or Congenital Lung Disease risk groups as well as premature babies born before the 33rd week of gestation.

Orally Efficacious Broad-Spectrum Ribonucleoside Analog Inhibitor of Influenza and Respiratory Syncytial Viruses

Morbidity and mortality resulting from influenza-like disease are a threat, especially for older adults. To improve case management, next-generation broad-spectrum antiviral therapeutics that are efficacious against major drivers of influenza-like disease, including influenza viruses and respiratory syncytial virus (RSV), are urgently needed. Using a dual-pathogen high-throughput screening protocol for influenza A virus (IAV) and RSV inhibitors, we have identified N⁴-hydroxycytidine (NHC) as a potent inhibitor of RSV, influenza B viruses, and IAVs of human, avian, and swine origins. Biochemical in vitro polymerase assays and viral RNA sequencing revealed that the ribonucleotide analog is incorporated into nascent viral RNAs in place of cytidine, increasing the frequency of viral mutagenesis. Viral passaging in cell culture in the presence of an inhibitor did not induce robust resistance. Pharmacokinetic profiling demonstrated dose-dependent oral bioavailability of 36 to 56%, sustained levels of the active 5'-triphosphate anabolite in primary human airway cells and mouse lung tissue, and good tolerability after extended dosing at 800 mg/kg of body weight/day. The compound was orally efficacious against RSV and both seasonal and highly pathogenic avian IAVs in mouse models, reducing lung virus loads and alleviating disease biomarkers. Oral dosing reduced IAV burdens in a guinea pig transmission model and suppressed virus spread to uninfected contact animals through direct transmission. Based on its broad-spectrum efficacy and pharmacokinetic properties, NHC is a promising candidate for future clinical development as a treatment option for influenza-like diseases.

Hospitalization costs and length of stay of Japanese children with respiratory syncytial virus: A structural equation modeling approach

BACKGROUND

This study sought to identify factors that impact the total health care costs associated with hospitalization of young Japanese children with respiratory syncytial virus (RSV).

METHODS

Children admitted between April 2014 and March 2015 with at least a confirmed diagnosis of RSV and 2 days of hospital stay were considered for inclusion. Data analyses of hospital claims were performed using a structural equation modeling approach.

RESULTS

A total of 6811 Japanese inpatients (<5 years old) diagnosed with RSV were included. The average length of stay was 7.5 days with a mean total health care cost of US Dollars (USD) $3344 per hospitalization. Intensive care unit hospitalizations were associated with greater costs (USD +$4951) compared to routine hospitalizations. The highest procedure-related cost drivers were blood transfusions (USD +$6402) and tube feedings (USD +$3512).

CONCLUSION

The economic burden of RSV-related infection hospitalizations in Japan is considerable. Efforts should be toward immunization and therapeutic treatment strategies that reduce severity, prevent, or reduce the duration of hospitalization.

Palivizumab Prophylaxis for Respiratory Syncytial Virus: Examining the Evidence Around Value

Respiratory syncytial virus (RSV) infection is the most common cause of lower respiratory tract infection and the leading cause of hospitalization among young children, incurring high annual costs among US children under the age of 5 years. Palivizumab has been found to be effective in reducing hospitalization and preventing serious lower respiratory tract infections in high-risk infants. This paper presents a systematic review of the cost-effectiveness studies of palivizumab and describes the main highlights of a round table discussion with clinical, payer, economic, research method, and other experts. The objectives of the discussion were to (1) review the current state of clinical, epidemiology, and economic data related to severe RSV disease; (2) review new cost-effectiveness estimates of RSV immunoprophylaxis in US preterm infants, including a review of the field’s areas of agreement and disagreement; and (3) identify needs for further research.

Cost-utility analysis of Palivizumab for Respiratory Syncytial Virus infection prophylaxis in preterm infants: update based on the clinical evidence in Spain

Background

This study aimed at estimating the efficiency of palivizumab in the prevention of Respiratory Syncytial Virus (RSV) infection and its sequelae in preterm infants (32^{day 1}-35^{day 0}weeks of gestational age –wGA-) in Spain.

Methods

A decision-tree model was developed to compare health benefits (Quality Adjusted Life Years-QALYs) and costs of palivizumab versus a non-prophylaxis strategy over 6 years. A hypothetical cohort of 1,000 preterm infants, 32^{day 1}-35^{day 0} wGA (4.356 kg average weight) at the beginning of the prophylaxis (15 mg/kg of palivizumab; 3.88 average number of injections per RSV season) was analysed.

The model considered the most recent evidence from Spanish observational and epidemiological studies on RSV infection: the FLIP II study provided hospital admission and Intensive Care Unit (ICU) admission rates; in-hospital mortality rate was drawn from an epidemiological study from 2004 to 2012; recurrent wheezing rates associated to RSV infection from SPRING study were adjusted by the evidence on the palivizumab effect from clinical trials. Quality of life baseline value, number of hospitalized infants and the presence of recurrent wheezing over time were granted to estimate QALYs.

National Health Service and societal perspective (included also recurrent wheezing indirect cost) were analysed. Total costs (€, 2016) included pharmaceutical and administration costs, hospitalization costs and recurrent wheezing management annual costs. A discount rate of 3.0% was applied annually for both costs and health outcomes.

Results

Over 6 years, the base case analysis showed that palivizumab was associated to an increase of 0.0731 QALYs compared to non-prophylaxis. Total costs were estimated in €2,110.71 (palivizumab) and €671.68 (non-prophylaxis) from the National Health System (NHS) perspective, resulting in an incremental cost utility ratio (ICUR) of €19,697.69/QALYs gained (prophylaxis vs non-prophylaxis). Results derived from the risk-factors population subgroups analysed were in line with the total population results. From the societal perspective, the incremental cost associated to palivizumab decreased to an €1,253.14 (ICUR = €17,153.16€/QALYs gained for palivizumab vs non-prophylaxis). One-way and probabilistic sensitivity analyses confirmed the robustness of the model.

Conclusions

The prophylaxis with palivizumab is efficient for preventing from RSV infections in preterm infants 32^{day 1}-35^{day 0} wGA in Spain.

Electronic supplementary material

The online version of this article (10.1186/s12879-017-2803-0) contains supplementary material, which is available to authorized users.

The Helminth-Derived Immunomodulator AvCystatin Reduces Virus Enhanced Inflammation by Induction of Regulatory IL-10+ T Cells

Respiratory Syncytial Virus (RSV) is a major pathogen causing low respiratory tract disease (bronchiolitis), primarily in infants. Helminthic infections may alter host immune responses to both helminths and to unrelated immune triggers. For example, we have previously shown that filarial cystatin (AvCystatin/Av17) ameliorates allergic airway inflammation. However, helminthic immunomodulators have so far not been tested in virus-induced disease. We now report that AvCystatin prevents Th2-based immunopathology in vaccine-enhanced RSV lung inflammation, a murine model for bronchiolitis. AvCystatin ablated eosinophil influx, reducing both weight loss and neutrophil recruitment without impairing anti-viral immune responses. AvCystatin also protected mice from excessive inflammation following primary RSV infection, significantly reducing neutrophil influx and cytokine production in the airways. Interestingly, we found that AvCystatin induced an influx of CD4⁺ FoxP3⁺ interleukin-10-producing T cells in the airway and lungs, correlating with immunoprotection, and the corresponding cells could also be induced by adoptive transfer of AvCystatin-primed F4/80⁺ macrophages. Thus, AvCystatin ameliorates enhanced RSV pathology without increasing susceptibility to, or persistence of, viral infection and warrants further investigation as a possible therapy for virus-induced airway disease.

Delta inulin-derived adjuvants that elicit Th1 phenotype following vaccination reduces respiratory syncytial virus lung titers without a reduction in lung immunopathology

Respiratory syncytial virus (RSV) is a significant cause of lower respiratory tract infections resulting in bronchiolitis and even mortality in the elderly and young children/infants. Despite the impact of this virus on human health, no licensed vaccine exists. Unlike many other viral infections, RSV infection or vaccination does not induce durable protective antibodies in humans. In order to elicit high titer, neutralizing antibodies against RSV, we investigated the use of the adjuvant Advax™, a novel polysaccharide adjuvant based on delta inulin microparticles, to enhance antibody titers following vaccination. BALB/c mice were vaccinated intramuscularly with live RSV as a vaccine antigen in combination with one of two formulations of Advax™. Advax-1 was comprised of the standard delta inulin adjuvant and Advax-2 was formulated delta inulin plus CpG oligodendronucleotides (ODNs). An additional group of mice were either mock vaccinated, immunized with vaccine only, or administered vaccine plus Imject Alum. Following 3 vaccinations, mice had neutralizing antibody titers that correlated with reduction in viral titers in the lungs. Advax-1 significantly enhanced serum RSV-specific IgG1 levels at week 6 indicative of a Th2 response, similar to titers in mice administered vaccine plus Imject Alum. In contrast, mice vaccinated with vaccine plus Advax-2 had predominately IgG2a titers indicative of a Th1 response that was maintained during the entire study. Interestingly, regardless of which AdvaxTM adjuvant was used, the neutralizing titers were similar between groups, but the viral lung titers were significantly lower (∼10E+3pfu/g) in mice administered vaccine with either AdvaxTM adjuvant compared to mice administered adjuvants only. The lung pathology in vaccinated mice with AdvaxTM was similar to Imject Alum. Overall, RSV vaccine formulated with AdvaxTM had high neutralizing antibody titers with low lung viral titers, but exacerbated lung pathology compared to unvaccinated mice.

Association Between Updated Guideline-Based Palivizumab Administration and Hospitalizations for Respiratory Syncytial Virus Infections

BACKGROUND

Since its introduction, palivizumab has been used to prevent respiratory syncytial virus (RSV) infection in high-risk populations. Recommendations for palivizumab administration changed in 2014. We examined whether adherence to 2014 palivizumab guidelines affected RSV hospitalization rates.

METHODS

This was a retrospective sequential period analysis comparing the incidence of RSV hospitalization in patients younger than 2 years of age before and after implementation of 2014 palivizumab use criteria. Hospitalization data were prospectively collected through age-based surveillance for the post-2014 guideline period (November 1, 2014 to April 1, 2015 RSV season). Comparative data were collected retrospectively for hospitalizations during the pre-2014 guideline period of 2 previous RSV seasons (November 1, 2012 to April 1, 2013 and November 1, 2013 to April 1, 2014). The primary outcome was RSV hospitalization rate, and number of palivizumab doses administered was analyzed as a secondary outcome.

RESULTS

During the study period, 194 RSV hospitalizations occurred. The rate of RSV hospitalization was 5.37 per 1000 children <24 months in the pre-2014 guideline period versus 5.78 per 1000 children <24 months in the post-2014 guideline period (difference of +0.4, 95% confidence interval: -1.2 to +2, P = 0.622). During the pre-2014 guideline period, 21.7 doses per 1000 children <24 months of palivizumab were administered, which decreased to 10.3 doses per 1000 children <24 months in the post-2014 guideline period, yielding a reduction of 11.4 doses per 1000 children <24 months (95% confidence interval: 14.3-8.4, P < 0.001).

CONCLUSIONS

The implementation of 2014 palivizumab use criteria was not associated with an increased incidence of RSV hospitalization for children younger than 2 years of age but was associated with significantly less use of palivizumab.

Measles Virus Fusion Protein: Structure, Function and Inhibition

Measles virus (MeV), a highly contagious member of the Paramyxoviridae family, causes measles in humans. The Paramyxoviridae family of negative single-stranded enveloped viruses includes several important human and animal pathogens, with MeV causing approximately 120,000 deaths annually. MeV and canine distemper virus (CDV)-mediated diseases can be prevented by vaccination. However, sub-optimal vaccine delivery continues to foster MeV outbreaks. Post-exposure prophylaxis with antivirals has been proposed as a novel strategy to complement vaccination programs by filling herd immunity gaps. Recent research has shown that membrane fusion induced by the morbillivirus glycoproteins is the first critical step for viral entry and infection, and determines cell pathology and disease outcome. Our molecular understanding of morbillivirus-associated membrane fusion has greatly progressed towards the feasibility to control this process by treating the fusion glycoprotein with inhibitory molecules. Current approaches to develop anti-membrane fusion drugs and our knowledge on drug resistance mechanisms strongly suggest that combined therapies will be a prerequisite. Thus, discovery of additional anti-fusion and/or anti-attachment protein small-molecule compounds may eventually translate into realistic therapeutic options.

Have Changing Palivizumab Administration Policies Led to More Respiratory Morbidity in Infants Born at 32-35 Weeks?

OBJECTIVES

To determine differences in the incidence of respiratory morbidity during the first year of life among infants born 32(0/7)-34(6/7) weeks' gestational age (GA) before and after the administration policy for palivizumab, as written by the American Academy of Pediatrics, was updated in 2009.

STUDY DESIGN

Secondary analysis of the dataset collected for the Gastrointestinal Risk Factors for Wheezing in Premature Infants study, which enrolled preterm infants without bronchopulmonary dysplasia and followed them by parental questionnaires at 3, 6, 9, and 12 months adjusted age for prematurity. Participants were included if they were enrolled in Gastrointestinal Risk Factors for Wheezing in Premature Infants, born 32(0/7)-34(6/7) weeks' GA, and completed the 12-month questionnaire. We compared rates of recurrent wheezing, respiratory medication use, and health care use before (Epoch 1) and after (Epoch 2) the 2009 administration policy change.

RESULTS

A total of 165 infants met inclusion criteria. There was a significant increase in recurrent wheezing in Epoch 2 (46.2%) vs Epoch 1 (28.8%) (OR 2.22 [95% CI 1.08-4.53], P = .03). There was a nonsignificant increase in visits to the emergency department in Epoch 2 (27.4%) vs Epoch 1 (15.3%) (OR 2.12 [95% CI 0.91-4.96], P = .08). There were no differences in hospital admissions or respiratory medication use.

CONCLUSIONS

Infants born 32(0/7)-34(6/7) weeks' GA treated after the American Academy of Pediatrics administration policy change in 2009 had a greater incidence of recurrent wheezing than those treated according to the previous policy. It will be important to track rates of recurrent wheezing after the 2014 administration policy, because it may be an important factor in future cost-effectiveness analyses.

Prematurity and the burden of influenza and respiratory syncytial virus disease

BACKGROUND

Respiratory morbidity of former preterm infants and especially those with bronchopulmonary dysplasia (BPD) is high during infancy and early childhood.

DATA SOURCES

We performed a review based on a literature search including EMBASE, MEDLINE, and CINAHL databases to identify all relevant papers published in the English and German literature on influenza and respiratory syncytial virus infection associated with preterm infant, prematurity, and BPD between 1980 and 2014.

RESULTS

Recurrent respiratory symptoms remain common at preschool age, school age and even into young adulthood. Acute viral respiratory tract infections due to different pathogens cause significant morbidity and necessitate rehospitalizations during the first years of life. Influenza virus infection plays a minor role compared to respiratory syncytial virus (RSV) associated respiratory tract infection during infancy and early childhood. Nevertheless, particular morbidity to both viruses is high.

CONCLUSIONS

The particular burden of both viral diseases in preterm infants is dominated by RSV and its associated rehospitalizations during the first two years of life. Prophylactic measures include vaccination against influenza virus of family members and caregivers and active immunization starting at the age of 6 months, and monthly injections of palivizumab during the cold season to avoid severe RSV disease and its sequelae.

Risk of respiratory syncytial virus infection in preterm infants: reviewing the need for prevention

Premature infants are at substantial risk for a spectrum of morbidities that are gestational age dependent. Respiratory syncytial virus (RSV) infection is most common in the first two years of life with the highest burden in children aged <6 months. Preterm infants ≤35 weeks' gestation are handicapped by incomplete immunological and pulmonary maturation and immature premorbid lung function with the added risk of bronchopulmonary dysplasia. Superimposed RSV infection incites marked neutrophilic airway inflammation and innate immunological responses that further compromise normal airway modeling. This review addresses the epidemiology and burden of RSV disease, focusing on the preterm population. Risk factors that determine RSV-disease severity and hospitalization and the impact on healthcare resource utilization and potential long-term respiratory sequelae are discussed. The importance of disease prevention and the evidence-based rationale for prophylaxis with palivizumab is explored, while awaiting the development of a universal vaccine.

Replication-Competent Influenza Virus and Respiratory Syncytial Virus Luciferase Reporter Strains Engineered for Co-Infections Identify Antiviral Compounds in Combination Screens

Myxoviruses such as influenza A virus (IAV) and respiratory syncytial virus (RSV) are major human pathogens, mandating the development of novel therapeutics. To establish a high-throughput screening protocol for the simultaneous identification of pathogen- and host-targeted hit candidates against either pathogen or both, we have attempted co-infection of cells with IAV and RSV. However, viral replication kinetics were incompatible, RSV signal window was low, and an IAV-driven minireplicon reporter assay used in initial screens narrowed the host cell range and restricted the assay to single-cycle infections. To overcome these limitations, we developed an RSV strain carrying firefly luciferase fused to an innovative universal small-molecule assisted shut-off domain, which boosted assay signal window, and a hyperactive fusion protein that synchronized IAV and RSV reporter expression kinetics and suppressed the identification of RSV entry inhibitors sensitive to a recently reported RSV pan-resistance mechanism. Combined with a replication-competent recombinant IAV strain harboring nanoluciferase, the assay performed well on a human respiratory cell line and supports multicycle infections. Miniaturized to 384-well format, the protocol was validated through screening of a set of the National Institutes of Health Clinical Collection (NCC) in quadruplicate. These test screens demonstrated favorable assay parameters and reproducibility. Application to a LOPAC library of bioactive compounds in a proof-of-concept campaign detected licensed antimyxovirus therapeutics, ribavirin and the neuraminidase inhibitor zanamivir, and identified two unexpected RSV-specific hit candidates, Fenretinide and the opioid receptor antagonist BNTX-7. Hits were evaluated in direct and orthogonal dose-response counterscreens using a standard recRSV reporter strain expressing Renilla luciferase.

Blocking Respiratory Syncytial Virus Entry: A Story with Twists

Respiratory syncytial virus (RSV) is responsible for majority of infant hospitalizations due to viral infections. Despite its clinical importance, no vaccine against RSV or effective antiviral therapy is available. Several structural classes of small-molecule RSV entry inhibitor have been described and one compound has advanced to clinical testing. Mutations in either one of two resistance hot spots in the F protein mediate unusual pan-resistance to all of these inhibitor classes. Based on the biochemical characterization of resistant viruses and structural insight into the RSV F trimer, we propose a kinetic escape model as the origin of pan-resistance. Since a resistant RSV remained pathogenic in the mouse model, pan-resistance mutations could emerge rapidly in circulating RSV strains. We evaluate clinical implications and discuss consequences for the design of future RSV drug discovery campaigns.

Efficacy and optimization of palivizumab injection regimens against respiratory syncytial virus infection

IMPORTANCE

Infection with the respiratory syncytial virus (RSV) is the leading cause of hospitalizations in children, accounting for more than 90,000 hospitalizations every year in the United States. For children who are at risk for severe RSV infections, the American Academy of Pediatrics recommends immunoprophylaxis with a series of up to 5 injections of the antibody palivizumab administered monthly, beginning on November 1 of each year. However, many practitioners initiate injections at the onset of RSV season as indicated by local surveillance.

OBJECTIVES

To evaluate the effectiveness of current regimens for palivizumab injections across different cities and to design an optimized regimen.

DESIGN, SETTING, AND PARTICIPANTS

We performed a mathematical modeling study of the risk for hospitalization due to RSV infection. The model accounted for the pharmacokinetics of the antibody, the timing of the injections, and seasonal patterns of RSV, including geographic and year-to-year variability. We used the model to estimate the efficacy of current regimens, including the American Academy of Pediatrics recommendation, and to design a more effective injection regimen, the optimized fixed start (OFS), which uses city-specific initiation dates. Participants were the approximately 700,000 individuals who had specimens tested for RSV by National Respiratory and Enteric Virus Surveillance System laboratories in 18 US cities from July 1, 1994, through June 30, 2011 (a total of 725,741 tests).

INTERVENTIONS

Different palivizumab injection regimens.

MAIN OUTCOMES AND MEASURES

The primary outcome measure was reduction in hospitalizations due to RSV infections. The secondary measures were cost (number of palivizumab doses) and duration of protection (in days).

RESULTS

The American Academy of Pediatrics-recommended 5-injection regimen is expected to reduce hospitalization risk by a median of 2.7% (range, -2.2% to 6.1%) compared with the conventional regimen based on RSV surveillance. The 5-injection OFS regimen is expected to further reduce risk by a median of 6.8% (range, 4.9% to 14.8%), and the 4-injection OFS regimen is expected to achieve efficacy comparable to that of the conventional 5-injection regimen while reducing costs by 20%.

CONCLUSIONS AND RELEVANCE

Modified palivizumab regimens can improve protection for children at risk for severe outcomes of RSV infection and thereby lower rates of hospitalization due to RSV.

Discovery of imidazopyridine derivatives as highly potent respiratory syncytial virus fusion inhibitors

A series of imidazolepyridine derivatives were designed and synthesized according to the established docking studies. The imidazopyridine derivatives were found to have good potency and physical-chemical properties. Several highly potent compounds such as 8ji, 8jl, and 8jm were identified with single nanomolar activities. The most potent compound 8jm showed an IC50 of 3 nM, lower microsome clearance and no CYP inhibition. The profile of 8jm appeared to be superior to BMS433771, and supported further optimization.

Vitamin D deficiency and acute lower respiratory infections in children younger than 5 years: identification and treatment

INTRODUCTION

Acute lower respiratory infection (ALRI) is a leading cause of childhood mortality. Research suggests that vitamin D deficiency (VDD) puts children at risk for ALRI. The purpose of this review is to examine ALRI and VDD in children 5 years and younger. Common etiologies, diagnosis, prevention, treatment of ALRI, and recommendations for vitamin D supplementation are summarized.

METHOD

Databases were searched for studies investigating VDD and ALRI in children. Independent reviewers assessed the internal validity of the studies.

RESULTS

Of 18 studies examined, VDD was found to be associated with increased risk or severity of ALRI in 13 studies; associations were not found in 4 studies. In one study it was found that high maternal vitamin D levels was associated with ALRI in infants.

DISCUSSION

Vitamin D supplementation is a low-cost, low-risk intervention that providers should consider for children, especially those at high risk for ALRI. Practitioners should follow current recommendations when prescribing vitamin D supplementation for infants and children.

Social, economic, and health impact of the respiratory syncytial virus: a systematic search

BACKGROUND

Bronchiolitis caused by the respiratory syncytial virus (RSV) and its related complications are common in infants born prematurely, with severe congenital heart disease, or bronchopulmonary dysplasia, as well as in immunosuppressed infants. There is a rich literature on the different aspects of RSV infection with a focus, for the most part, on specific risk populations. However, there is a need for a systematic global analysis of the impact of RSV infection in terms of use of resources and health impact on both children and adults. With this aim, we performed a systematic search of scientific evidence on the social, economic, and health impact of RSV infection.

METHODS

A systematic search of the following databases was performed: MEDLINE, EMBASE, Spanish Medical Index, MEDES-MEDicina in Spanish, Cochrane Plus Library, and Google without time limits. We selected 421 abstracts based on the 6,598 articles identified. From these abstracts, 4 RSV experts selected the most relevant articles. They selected 65 articles. After reading the full articles, 23 of their references were also selected. Finally, one more article found through a literature information alert system was included.

RESULTS

The information collected was summarized and organized into the following topics: 1. Impact on health (infections and respiratory complications, mid- to long-term lung function decline, recurrent wheezing, asthma, other complications such as otitis and rhino-conjunctivitis, and mortality; 2. Impact on resources (visits to primary care and specialists offices, emergency room visits, hospital admissions, ICU admissions, diagnostic tests, and treatments); 3. Impact on costs (direct and indirect costs); 4. Impact on quality of life; and 5. Strategies to reduce the impact (interventions on social and hygienic factors and prophylactic treatments).

CONCLUSIONS

We concluded that 1. The health impact of RSV infection is relevant and goes beyond the acute episode phase; 2. The health impact of RSV infection on children is much better documented than the impact on adults; 3. Further research is needed on mid- and long-term impact of RSV infection on the adult population, especially those at high-risk; 4. There is a need for interventions aimed at reducing the impact of RSV infection by targeting health education, information, and prophylaxis in high-risk populations.

Cross-resistance mechanism of respiratory syncytial virus against structurally diverse entry inhibitors

Respiratory syncytial virus (RSV) is a leading pediatric pathogen that is responsible for a majority of infant hospitalizations due to viral disease. Despite its clinical importance, no vaccine prophylaxis against RSV disease or effective antiviral therapeutic is available. In this study, we established a robust high-throughput drug screening protocol by using a recombinant RSV reporter virus to expand the pool of RSV inhibitor candidates. Mechanistic characterization revealed that a potent newly identified inhibitor class blocks viral entry through specific targeting of the RSV fusion (F) protein. Resistance against this class was induced and revealed overlapping hotspots with diverse, previously identified RSV entry blockers at different stages of preclinical and clinical development. A structural and biochemical assessment of the mechanism of unique, broad RSV cross-resistance against structurally distinct entry inhibitors demonstrated that individual escape hotspots are located in immediate physical proximity in the metastable conformation of RSV F and that the resistance mutations lower the barrier for prefusion F triggering, resulting in an accelerated RSV entry kinetics. One resistant RSV recombinant remained fully pathogenic in a mouse model of RSV infection. By identifying molecular determinants governing the RSV entry machinery, this study spotlights a molecular mechanism of broad RSV resistance against entry inhibition that may affect the impact of diverse viral entry inhibitors presently considered for clinical use and outlines a proactive design for future RSV drug discovery campaigns.

Updated guidance for palivizumab prophylaxis among infants and young children at increased risk of hospitalization for respiratory syncytial virus infection

Guidance from the American Academy of Pediatrics (AAP) for the use of palivizumab prophylaxis against respiratory syncytial virus (RSV) was first published in a policy statement in 1998. Guidance initially was based on the result from a single randomized, placebo-controlled clinical trial conducted in 1996-1997 describing an overall reduction in RSV hospitalization rate from 10.6% among placebo recipients to 4.8% among children who received prophylaxis. The results of a second randomized, placebo-controlled trial of children with hemodynamically significant heart disease were published in 2003 and revealed a reduction in RSV hospitalization rate from 9.7% in control subjects to 5.3% among prophylaxis recipients. Because no additional controlled trials regarding efficacy were published, AAP guidance has been updated periodically to reflect the most recent literature regarding children at greatest risk of severe disease. Since the last update in 2012, new data have become available regarding the seasonality of RSV circulation, palivizumab pharmacokinetics, the changing incidence of bronchiolitis hospitalizations, the effects of gestational age and other risk factors on RSV hospitalization rates, the mortality of children hospitalized with RSV infection, and the effect of prophylaxis on wheezing and palivizumab-resistant RSV isolates. These data enable further refinement of AAP guidance to most clearly focus on those children at greatest risk.

Respiratory Syncytial Virus Infection in High-risk Infants - an Update on Palivizumab Prophylaxis

Morbidity due to respiratory syncytial virus (RSV) disease is still high in infants and children worldwide during the first two to five years of life. Certain categories of high-risk infants with increased morbidity and mortality attributed to RSV disease have been identified and are included in national recommendations for prophylaxis with the monoclonal RSV antibody palivizumab. Most guidelines recommend palivizumab for preterm infants born less than or equal to 32 weeks gestational age with or without bronchopulmonary dysplasia, those born between 33 and 35 weeks gestational age with additional risk factors, and infants and children with hemodynamically significant congenital heart disease. Over the last years several rare diseases have been identified demonstrating high morbidity associated with RSV disease, thus, extension of guidelines for the prophylaxis with palivizumab for these patients with rare diseases including children with malignancy, congenital and acquired immune deficiency, Down syndrome, neuromuscular impairment, cystic fibrosis, congenital diaphragmatic hernia and other severe respiratory disease is increasingly discussed. Efficacy of palivizumab prophylaxis is documented by meta-analysis, and different economic analyses demonstrate cost-effectiveness of palivizumab for the most common indications during the first RSV season.

Glycan variants of a respiratory syncytial virus antibody with enhanced effector function and in vivo efficacy

Respiratory syncytial virus (RSV) can cause devastating lower respiratory tract infections in preterm infants or when other serious health problems are present. Immunoprophylaxis with palivizumab (Synagis), a humanized IgG1 mAb, is the current standard of care for preventing RSV infection in at-risk neonates. We have explored the contribution of effector function to palivizumab efficacy using a plant-based expression system to produce palivizumab N-glycan structure variants with high homogeneity on different antibody isotypes. We compared these isotype and N-glycoform variants with commercially available palivizumab with respect to both in vitro receptor and C1q binding and in vivo efficacy. Whereas the affinity for antigen and neutralization activity of each variant were indistinguishable from those of palivizumab, their Fcγ receptor binding profiles were very different, which was reflected in either a reduced or enhanced ability to influence the RSV lung titer in challenged cotton rats. Enhanced Fcγ receptor binding was associated with reduced viral lung titers compared with palivizumab, whereas abrogation of receptor binding led to a drastic reduction in efficacy. The results support the hypotheses that classic antibody neutralization is a minor component of efficacy by palivizumab in the cotton rat and that antibody-dependent cell-mediated cytotoxicity activity can significantly enhance the efficacy of this antiviral mAb.

Respiratory syncytial virus immunization program for the United States: impact of performance determinants of a theoretical vaccine

OBJECTIVES

To inform strategic decisions on respiratory syncytial virus (RSV) vaccine development and identify critical endpoints likely to drive the vaccine's medical and economic impact.

DESIGN

A decision-analysis model populated using healthcare utilization data and costs from the literature; vaccine efficacy and duration based on assumptions.

SETTING

Vaccination in the physician office setting in the USA.

PARTICIPANTS

A hypothetical cohort of newborn infants.

INTERVENTION

Vaccination of children at low and high risk of respiratory sequelae with a theoretical RSV vaccine vs palivizumab prophylaxis for children at high risk.

OUTCOME MEASURES

Medical and economic value of RSV vaccination, including cost per quality adjusted life-year (QALY) gained.

RESULTS

Using base-case assumptions (efficacy 50% at birth; half-life 12 months), RSV vaccination would prevent 23,069 hospitalizations and 66 deaths per vaccinated birth cohort in the USA. Excluding vaccination costs, direct medical costs for RSV would reduce by $236 million, and income and productivity losses by $134 million. Assuming a vaccine cost per course similar to Rotarix® in the USA ($232 including administration fees), the cost per QALY gained would be $93,401 (95% CI: $65,815-$126,060) from the healthcare system perspective and $65,115 (95% CI: $41,003-$93,679) from the societal perspective. The net cost (healthcare system perspective) per life-year saved would be $216,120 (95% CI: $161,184-$263,981); the cost per hospitalization averted would be $19,172 (95% CI: $14,679-$22,093). Aside from efficacy, the vaccine's impact is sensitive to the start of protective immunity and the duration of protection.

CONCLUSIONS

Development of an RSV vaccine would substantially reduce inpatient hospitalizations and outpatient visits. It would also have an impact on infant mortality. To demonstrate the full medical and economic value of the vaccine, appropriate endpoints or endpoint surrogates for hospitalization, mortality, and total case reductions should be collected during vaccine development.