Cost-effectiveness of monoclonal antibody and maternal immunization against respiratory syncytial virus (RSV) in infants: Evaluation for six European countries

Cost-effectiveness analysis of nirsevimab for prevention of respiratory syncytial virus disease among infants in Shanghai, China: A modeling study

Chinese authority approved nirsevimab to prevent respiratory syncytial virus (RSV) in January 2024. We aimed to assess the cost-effectiveness of nirsevimab immunization among infants in Shanghai. A decision-tree Markov model was developed to compare two strategies - year-round and seasonal immunization - with nonintervention, from a societal perspective, using RSV-associated disease burden and demographic data. Twelve monthly birth cohorts were followed through 24 one-month Markov cycles. Two scenarios of nirsevimab efficacy were considered: short-duration and long-duration. The incremental cost-effectiveness ratio (ICER) (incremental costs per quality-adjusted life year [QALY] gained) was calculated and the willingness-to-pay (WTP) threshold was set at gross domestic product (GDP) per capita. Sensitivity analysis was performed to evaluate the uncertainty. Both immunization strategies demonstrated cost-effectiveness across efficacy scenarios, with seasonal approach yielding lower ICERs than the year-round approach. The cost-effectiveness of the seasonal approach was influenced by the timing of its administration. Nirsevimab immunization may be an economically favorable strategy for infant RSV prevention in Shanghai. The optimal program timing of seasonal immunization requires further investigation to maximize public health impact.

Respiratory syncytial virus vaccination: likely and less likely outcomes

PURPOSE OF REVIEW

Respiratory syncytial virus (RSV) remains a leading cause of lower respiratory tract infections in infants, older adults, and high-risk populations. The recent approval of new RSV vaccines and monoclonal antibodies marks a turning point in RSV prevention. This review explores these advancements, their immediate and potential long-term effects, and the remaining challenges.

RECENT FINDINGS

Several novel RSV prevention strategies have been approved, including maternal RSVPreF vaccines, infant-targeted monoclonal antibodies like Nirsevimab, and vaccines for older adults. These interventions significantly reduce RSV-related hospitalizations, ICU admissions, and mortality, particularly in high-risk groups. Early evidence also suggests benefits in reducing wheezing during infancy; however, long-term impacts on asthma development remain uncertain. Challenges such as vaccine hesitancy and limited access in low-resource settings remain pressing issues that require sustained focus.

SUMMARY

RSV vaccines and monoclonal antibodies are expected to alter clinical management and public health by reducing severe disease burden and RSV transmission. Further research is needed to evaluate their long-term effects, including implications for asthma prevention and pediatric obstructive sleep apnea. Addressing access disparities and public acceptance will be critical for maximizing their global impact.

Estimated impact of nirsevimab prophylaxis on the economic burden of respiratory syncytial virus disease in Northern Italy

BACKGROUND

Respiratory syncytial virus (RSV) is a frequent cause of acute lower respiratory tract infection (LRTI) in infants; however, the health and economic burden of infant RSV-associated LRTI in Northern Italy has not been sufficiently assessed. We evaluated the clinical and economic burden of RSV-associated LRTI requiring emergency department (ED) access and/or hospitalization in infants less than 6 months old in two provinces in Northern Italy and estimated the potential impact of universal immunization with a recently approved monoclonal antibody.

METHODS

Epidemiological data during the 2021-2022 and 2022-2023 RSV seasons were obtained from administrative records and anonymized to comply with confidentiality requirements. Resource utilization was estimated using the costs associated with each event, obtained from the available literature and an analysis of national hospital discharge records. A static decision analytic model was used to estimate RSV-related health and associated cost outcomes.

RESULTS

Overall, 882 ED accesses and 430 hospital admissions associated with RSV were recorded during two consecutive epidemic seasons. Intensive care admission was needed in 85 cases. Universal immunization would avoid 406 ED accesses and 199 hospital admissions. The total economic burden was estimated at over €1.5 million, of which 51% was for hospitalization, 20% for intensive care, and 9% for ED access. An additional 10% was estimated for the management of long-term consequences of RSV-associated LRTI. Universal immunization would avoid expenses of €124,092 for ED accesses and €999,629 for hospital admissions.

CONCLUSIONS

These findings underscore the substantial health and economic burden of RSV disease, highlighting the potential benefits of universal prevention strategies, while informing policymaker decisions regarding implementation of immunoprophylaxis.

Disease burden estimates in economic evaluation studies of respiratory syncytial virus (RSV) maternal immunization: a systematic review

INTRODUCTION

Recently, new technologies have emerged for the prevention of respiratory syncytial virus (RSV) infections. Reliable epidemiological data are essential for accurately assessing the disease burden and informing health economic evaluations (HEE). This review evaluates how HEE of RSV maternal vaccination (MV) estimated the RSV disease burden.

METHODS

A systematic search was conducted in MEDLINE, SCOPUS, EMBASE, NHS EED, HTA, Tufts CEA Registry, LILACS, and Web of Science for full HEE of RSV MV. Reporting quality was assessed with the CHEERS 2022 checklist, costs were converted to 2024 U.S. dollars, and a descriptive, interpretive synthesis of the data was performed.

RESULTS

All 21 included studies were cost-utility analyses, 10 conducted in high-income countries. The HEE utilized a wide range of data sources to build epidemiological estimates, frequently relying on non-local data, particularly for outpatient rates. National data on RSV hospitalization rates were the most commonly available. No study included equity assessments. The maternal vaccine dose price was identified as a critical factor in the strategy's cost-effectiveness.

CONCLUSION

Enhancing local data availability for RSV, by strengthening the respiratory virus surveillance, is crucial to improve the reliability of HEE of RSV prevention strategies and enable more informed and effective policy decisions.

REGISTRATION

PROSPERO: CRD42024549989.

Cost-Effectiveness Analysis of Nirsevimab for Preventing Respiratory Syncytial Virus-Related Lower Respiratory Tract Disease in Dutch Infants: An Analysis Including All-Infant Protection

OBJECTIVES

This study aimed to assess the cost effectiveness of nirsevimab, a recently authorized monoclonal antibody (mAb) for the prevention of lower respiratory tract disease (LRTD) caused by respiratory syncytial virus (RSV), in comparison with the standard practice involving palivizumab for high-risk infants during their first RSV season in the Netherlands.

METHODS

A static cost-effectiveness model was populated for the Netherlands to evaluate different immunization strategies for nirsevimab over a single RSV season from a societal perspective. The model considered the most recently published RSV incidence data (average incidence from 2006 to2018), costs (adjusted to the 2023 price year), and associated health effects. Extensive scenario analyses were conducted to explore various strategies, and sensitivity analysis was performed to assess the model's robustness.

RESULTS

In the base-case scenario, all-infant protection-a strategy of in-season with catch-up immunization for all infants-nirsevimab has the potential to prevent numerous RSV-related cases, including 2333 hospitalizations and 150 intensive-care admissions, in the overall population compared with the standard of care. Nirsevimab appears to be cost effective under this strategy with an economically justifiable acquisition price for nirsevimab of €220 at a willingness-to-pay threshold of €50,000 per quality-adjusted life-year. Sensitivity analyses indicate a 52% probability that nirsevimab is cost effective at this threshold. Comparison of different vaccination strategies revealed that the all-infant protection approach was the one that prevented the higher number of cases.

CONCLUSIONS

This study indicates that universal infant immunization with nirsevimab has the potential to be cost effective and significantly reduces the burden of RSV among Dutch infants. These findings underscore the importance of implementing effective protective measures against RSV-LRTD, reducing the pressure on the healthcare system during the RSV season.

Rapid In Vivo Screening of Monoclonal Antibody Cocktails Using Hydrodynamic Delivery of DNA-Encoded Modified Antibodies

Background: Monoclonal antibodies (mAbs) are potent treatment options for infectious diseases. The rapid isolation and in vivo validation of therapeutic mAb candidates, including mAb cocktails, are essential to combat novel or rapidly mutating pathogens. The rapid selection and production of mAb candidates in sufficient amount and quality for preclinical studies are a major limiting step in the mAb development pipeline. Methods: Here, we developed a method to facilitate the screening of therapeutic mAbs in mouse models. Four conventional mAbs were transformed into single-chain variable fragments fused to the fragment crystallizable (Fc) region of a human IgG1 (scFv-IgG). These scFv-IgG were expressed individually or as a cocktail in vitro and in mice following transfection or hydrodynamic delivery of the corresponding plasmids. Results: This method induced high expression of all scFv-IgG and provided protection in two murine infection models. Conclusions: This study highlights the benefits of this approach for the rapid, low-cost screening of therapeutic mAb candidates.

Cost-effectiveness of tislelizumab versus sorafenib as first-line treatment for unresectable hepatocellular carcinoma: a comparative analysis in China, the United States and Europe

BACKGROUND

Tislelizumab has emerged as a promising therapy for unresectable hepatocellular carcinoma (uHCC), although its economic viability across different healthcare systems remains uncertain.

AIM

This study compared the cost-effectiveness of tislelizumab versus sorafenib as a first-line treatment for uHCC from the perspectives of the healthcare systems of China, the United States and Europe.

METHOD

A partitioned survival model was developed using data from the RATIONALE-301 trial. Costs and utilities were sourced from local healthcare charges, publicly available databases, and published literature. Total costs, quality-adjusted life years, and incremental cost-effectiveness ratios (ICERs) were assessed. Price simulations were conducted to identify cost-effective pricing within established willingness-to-pay (WTP) thresholds. Sensitivity and scenario analyses were performed to test the robustness of the model.

RESULTS

Tislelizumab (priced at $1587.45/100 mg) was cost-effective in the US at a WTP threshold of $150,000, with an ICER of $108,812.52. In Europe, tislelizumab was cost-effective at a WTP threshold of $100,000, with an ICER of $94,880.40. For $186.18/100 mg in China, tislelizumab was cost-effective with an ICER of $14,206.80. Price simulation analyses showed that in the US, tislelizumab was favored when priced below $1438.30/100 mg at a $100,000 WTP threshold and below $2284.56/100 mg at a $150,000 WTP threshold. In Europe, it was favored below $1661.82/100 mg and $2501.93/100 mg for the same thresholds. In China, tislelizumab was cost-effective at a WTP threshold of $38,184 when priced below $582.11/100 mg.

CONCLUSION

Tislelizumab presents a cost-effective first-line treatment option for uHCC, potentially supporting its broader adoption in health policy. Future research should focus on long-term efficacy and real-world data to further validate these findings.

Impact of RSVpreF vaccination on reducing the burden of respiratory syncytial virus in infants and older adults

Respiratory syncytial virus (RSV) causes a substantial health burden among infants and older adults. Prefusion F protein-based vaccines have shown high efficacy against RSV disease in clinical trials, offering promise for mitigating this burden through maternal and older adult immunization. Employing an individual-based model, we evaluated the impact of RSV vaccination on hospitalizations and deaths in 13 high-income countries, assuming that the vaccine does not prevent infection or transmission. Using country-specific vaccine uptake rates for seasonal influenza, we found that vaccination of older adults would prevent hospitalizations by a median of 35-64% across the countries studied here. Vaccination of pregnant women could avert infant hospitalizations by 5-50%. Reductions in RSV-related mortality mirrored those estimated for hospitalizations. While substantial hospitalization costs could be averted, the impact of vaccination depends critically on uptake rates. Enhancing uptake and accessibility is crucial for maximizing the real-world impact of vaccination on reducing RSV burden among vulnerable populations.

The respiratory syncytial virus vaccine and monoclonal antibody landscape: the road to global access

Respiratory syncytial virus (RSV) is the second most common pathogen causing infant mortality. Additionally, RSV is a major cause of morbidity and mortality in older adults (age ≥60 years) similar to influenza. A protein-based maternal vaccine and monoclonal antibody (mAb) are now market-approved to protect infants, while an mRNA and two protein-based vaccines are approved for older adults. First-year experience protecting infants with nirsevimab in high-income countries shows a major public health benefit. It is expected that the RSV vaccine landscape will continue to develop in the coming years to protect all people globally. The vaccine and mAb landscape remain active with 30 candidates in clinical development using four approaches: protein-based, live-attenuated and chimeric vector, mRNA, and mAbs. Candidates in late-phase trials aim to protect young infants using mAbs, older infants and toddlers with live-attenuated vaccines, and children and adults using protein-based and mRNA vaccines. This Review provides an overview of RSV vaccines highlighting different target populations, antigens, and trial results. As RSV vaccines have not yet reached low-income and middle-income countries, we outline urgent next steps to minimise the vaccine delay.

RSV prevention options for infants and older adults: A specific expanding competitive arena

Respiratory Syncytial Virus (RSV) is an ubiquitous respiratory virus, which spreads like seasonal influenza throughout winter time in temperate climate countries. RSV infections are usually mild in healthy children and adults, but may be severe in premature infants, young children with congenital heart disease or chronic lung disease, immunocompromised individuals and frail elderly people. At present, the pharmaceutical options to prevent RSV negative effects can be divided into monoclonal antibodies (mABs) and vaccines (active immunization). The two mABs licensed so far are indicated only for infants, while the first vaccines approved are mainly recommended for older adults. The pharmaceutical competitive arena of products to prevent RSV negative effects has recently become very crowded after more than two decades with only one mAB as the unique option. Here, we try to put order in the dramatically increasing mix of very different products which have been recently launched. The aim of our effort is to provide some suggestions for European policy makers in order to limit the potentially relevant financial impact of these new expensive options on public pharmaceutical expenditures. We hope the suggested strategies might help to avoid transforming RSV from an apparently underscored health issue into a clearly overestimated health risk for the whole population in European countries. This dramatic change could be driven by a bunch of powerful multinational companies.

Disease Burden Associated with All Infants in Their First RSV Season in the UK: A Static Model of Universal Immunization with Nirsevimab Against RSV-Related Outcomes

INTRODUCTION

Respiratory syncytial virus (RSV) leads to significant morbidity in newborn infants in the United Kingdom (UK). Nirsevimab, a long-acting monoclonal antibody, received approval from the European Medicines Agency and has been licensed by the Medicines and Healthcare products Regulatory Agency for preventing RSV lower respiratory tract disease (LRTD) in neonates and infants during their first RSV season. The objective of this study was to assess the potential impact of nirsevimab on RSV-associated LRTDs, related costs, and loss of quality-adjusted life years (QALYs) in infants experiencing their first RSV season.

METHODS

The impact of administering nirsevimab across all infant populations compared to palivizumab in the high-risk palivizumab-eligible population was assessed via a static decision-analytic model specified for a UK birth cohort experiencing their first RSV season. The RSV-related health events of interest included primary care (PC), accident and emergency (A&E) visits, hospitalizations [including hospitalizations alone and those resulting in intensive care unit (ICU) admissions], recurrent wheezing in infants who were previously hospitalized, and all-cause LRTD hospitalizations.

RESULTS

Under the current standard of practice (SoP), RSV was estimated to result in 329,425 RSV LRTDs annually, including 24,381 hospitalizations and ICU admissions, representing £117.8 million (2024 GBP) in costs. Comparatively, universal immunization of all infants with nirsevimab could avoid 198,886 RSV LRTDs, including 16,657 hospitalizations and ICU admissions, resulting in savings of £77.2 million in RSV treatment costs. Considering the impact on all-cause LRTD of a universal immunization strategy, nirsevimab could be valued between £243 and £274, assuming willingness-to-pay (WTP) thresholds of £20,000 and £30,000 per QALY saved, respectively.

CONCLUSIONS

This analysis demonstrated that the health and economic burden of RSV would be substantially reduced in all infants experiencing their first RSV season in the UK (including term, preterm, and palivizumab-eligible infants) as a result of a universal immunization strategy with nirsevimab.

Nirsevimab: Alleviating the burden of RSV morbidity in young children

Respiratory syncytial virus (RSV) is the leading cause of acute lower respiratory tract infections (LRTIs) and hospital admissions in early childhood. Recent advancements in novel preventive therapies, including extended half-life monoclonal antibodies and antenatal vaccination, have afforded new opportunities to significantly reduce the burden of this infection. Nirsevimab is a novel monoclonal antibody that provides sustained protection against RSV for at least 5 months among newborns and young children. It has received regulatory approval in numerous countries and is being implemented across various settings. Two pivotal Phase 3 trials (MELODY, HARMONIE) demonstrated significant reductions in RSV-associated LRTI hospitalisations following nirsevimab administration, with treatment efficacy of 62.1% and 83.2%. Emerging real-world data from early adopters of nirsevimab corroborates these findings. Studies from Spain, Luxembourg, France and the USA report effectiveness rates between 82% and 90% in preventing RSV-associated hospitalisations among infants entering their first RSV season. Current implementation strategies for nirsevimab have primarily focused on seasonal administration for all infants, aligned to local RSV seasons, and often include catch-up doses for those born before the season begins. Available cost-effectiveness analyses indicate that while nirsevimab offers significant potential public health benefits, its adoption must carefully consider economic factors such as treatment costs, implementation strategies tailored to local viral epidemiology, and logistics for vaccine delivery. Overall, nirsevimab presents a promising opportunity to alleviate the burden of severe RSV infections in young children. However, ongoing surveillance and refinements in implementation strategies are crucial to optimise its impact and ensure sustainability across diverse health-care settings.

New Vaccines for Chronic Respiratory Patients

Chronic respiratory diseases (CRD) are responsible for more than four million deaths worldwide and have become especially prevalent in developed countries. Although the current therapies help manage daily symptoms and improve patients' quality of life, there is a major need to prevent exacerbations triggered mainly by respiratory infections. Therefore, CRD patients are a prime target for vaccination against infectious agents. In the present manuscript we review the state of the art of available vaccines specifically indicated in patients with CRDs. In addition to pneumococcus, influenza, pertussis, and SARS-CoV-2 vaccines, recently added immunization options like vaccines and monoclonal antibodies against respiratory syncytial virus, are particularly interesting in CRD patients. As new products reach the market, health authorities must be agile in updating immunization recommendations and in the programming of the vaccination of vulnerable populations such as patients with CRDs. Organizational and educational strategies might prove useful to increase vaccine uptake by CRD patients.

Cost-effectiveness of RSVpreF vaccine and nirsevimab for the prevention of respiratory syncytial virus disease in Canadian infants

BACKGROUND

Health Canada recently authorized the RSVpreF pregnancy vaccine and nirsevimab to protect infants against respiratory syncytial virus (RSV) disease.

OBJECTIVE

Assess the cost-effectiveness of RSVpreF and nirsevimab programs in preventing RSV disease in infants, compared to a palivizumab program.

METHODS

We used a static cohort model of a Canadian birth cohort during their first RSV season to estimate sequential incremental cost-effectiveness ratios (ICERs) in 2023 Canadian dollars per quality-adjusted life year (QALY) for nine strategies implemented over a one-year time period, from the health system and societal perspectives. Sensitivity and scenario analyses were conducted to explore the impact of uncertainties on the results.

RESULTS

All-infants nirsevimab programs averted more RSV-related outcomes than year-round RSVpreF programs, with the most RSV cases averted in a seasonal nirsevimab program with catch-up. Assuming list prices for these immunizing agents, all-infants nirsevimab and year-round RSVpreF programs were never cost-effective, with ICERs far exceeding commonly used cost-effectiveness thresholds. Seasonal nirsevimab with catch-up for infants born outside the RSV season was a cost-effective program if prioritized for infants at moderate/high-risk (ICER <$28,000 per QALY) or those living in settings with higher RSV burden and healthcare costs, such as remote communities where transport would be complex (ICER of $5700 per QALY). Using a $50,000 per QALY threshold, an all-infants nirsevimab program could be optimal if nirsevimab is priced at <$110-190 per dose. A year-round RSVpreF for all pregnant women and pregnant people plus nirsevimab for infants at high-risk was optimal if nirsevimab is priced at >$110-190 per dose and RSVpreF priced at <$60-125 per dose.

INTERPRETATION

Prophylactic interventions can substantially reduce RSV disease in infants, and more focused nirsevimab programs are the most cost-effective option at current product prices.

Healthcare costs related to respiratory syncytial virus in paediatric intensive care units in the Netherlands: a nationwide prospective observational study (the BRICK study)

Background

The implementation of the approved respiratory syncytial virus (RSV) preventive interventions in immunisation programmes is advancing rapidly. Insight into healthcare costs of RSV-related paediatric intensive care unit (PICU) admissions is lacking, but of great importance to evaluate the impact of implementation. Therefore, this study aimed to determine the total annual RSV-related paediatric intensive care healthcare costs in the Netherlands.

Methods

A nationwide prospective, observational, multicenter study was performed from September 2021 until June 2023. The total annual RSV-related healthcare costs on PICUs in the Netherlands were calculated using RSV-related costs (subgroup I) and consequential costs (subgroup II and III). Subgroup I comprised all PICU admitted infants ≤12 months of age with laboratory-confirmed RSV infection. Subgroup II and III consisted of postponed elective PICU admissions and refused acute PICU admissions due to RSV-related lack of PICU capacity.

Findings

A total of 424 infants with RSV-related PICU admission were included. Median age at PICU admission was 46 days (IQR 25-89). The median length of PICU admission was 5 days (IQR 3-8). The total RSV-related PICU costs are € 3,826,386 in 2021-2022, and € 3,183,888 in 2022-2023. Potential costs averted by RSV preventive interventions is € 1.9 to € 2.6 million depending on season, and the duration of protection.

Interpretation

RSV-related PICU admissions cost €3.1 to €3.8 million in the Netherlands during one season. The introduction of new RSV preventive interventions into the Dutch immunisation programme will generate significant cost-savings on PICUs and decreases the admission burden of PICUs.

Funding

None.

Cost-effectiveness Analysis of Maternal Immunization with RSVpreF Vaccine for the Prevention of Respiratory Syncytial Virus Among Infants in Spain

INTRODUCTION

Respiratory syncytial virus (RSV) is the leading cause of acute lower respiratory infections (ALRI) in children under one year of age. In high-income countries, RSV infections cause a significant overload of care every winter, imposing a significant burden to the healthcare system, which has made the development of prevention strategies a major global health priority. In this context, a new bivalent RSV prefusion F protein-based vaccine (RSVpreF) has recently been approved. The objective of this study was to evaluate the cost-effectiveness of vaccinating pregnant women with the RSVpreF vaccine to prevent RSV in infants from the Spanish National Healthcare System (NHS) perspective.

METHODS

A hypothetical cohort framework and a Markov-type process were used to estimate clinical outcomes, costs, quality-adjusted life years (QALY) and cost-per-QALY gained (willingness-to-pay threshold: €25,000/QALY) for newborn infants born to RSV-vaccinated versus unvaccinated mothers over an RSV season. The base case analysis was performed from the NHS perspective including direct costs (€2023) and applying a discount of 3% to future costs and outcomes. To evaluate the robustness of the model, several scenarios, and deterministic and probabilistic analyses were carried out. All the parameters and assumptions were validated by a panel of experts.

RESULTS

The results of the study showed that year-round maternal vaccination program with 70% coverage is a dominant option compared to no intervention, resulting in direct cost savings of €1.8 million each year, with an increase of 551 QALYs. Maternal vaccination could prevent 38% of hospital admissions, 23% of emergency room visits, 19% of primary care visits, and 34% of deaths due to RSV. All scenario analyses showed consistent results, and according to the probabilistic sensitivity analysis (PSA), the probability of maternal vaccination being cost-effective versus no intervention was 99%.

CONCLUSIONS

From the Spanish NHS perspective, maternal vaccination with bivalent RSVpreF is a dominant alternative compared with a non-prevention strategy.

Exploratory analysis of the economically justifiable price of nirsevimab for healthy late-preterm and term infants in Colombia

INTRODUCTION

Respiratory syncytial virus infection is the leading cause of lower respiratory infection globally. Recently, nirsevimab has been approved to prevent respiratory syncytial virus (RSV) infection. This study explores the economically justifiable price of nirsevimab for preventing RSV infection in Colombia's children under 1 year of age.

MATERIALS AND METHODS

A static model was developed using the decision tree microsimulation to estimate the quality-adjusted costs and life years of two interventions: a single intramuscular dose of nirsevimab versus not applying nirsevimab. This analysis was made during a time horizon of 1 year and from a societal perspective.

RESULTS

The annual savings in Colombia associated with this cost per dose ranged from U$ 2.5 to 4.1 million. Based on thresholds of U$ 4828, U$ 5128, and U$ 19 992 per QALY evaluated in this study, we established economically justifiable drug acquisition prices of U$ 21.88, U$ 25.04, and U$ 44.02 per dose of nirsevimab.

CONCLUSION

the economically justifiable cost for nirsevimab in Colombia is between U$ 21 to U$ 44 per dose, depending on the willingness to pay used to decide its implementation. This result should encourage more studies in the region that optimize decision-making processes when incorporating this drug into the health plans of each country.

Global Seasonal Activities of Respiratory Syncytial Virus Before the Coronavirus Disease 2019 Pandemic: A Systematic Review

Varied seasonal patterns of respiratory syncytial virus (RSV) have been reported worldwide. We conducted a systematic review on articles identified in PubMed reporting RSV seasonality based on data collected before 1 January 2020. RSV seasonal patterns were examined by geographic location, calendar month, analytic method, and meteorological factors including temperature and absolute humidity. Correlation and regression analyses were conducted to explore the relationship between RSV seasonality and study methods and characteristics of study locations. RSV seasons were reported in 209 articles published in 1973-2023 for 317 locations in 77 countries. Regular RSV seasons were similarly reported in countries in temperate regions, with highly variable seasons identified in subtropical and tropical countries. Longer durations of RSV seasons were associated with a higher daily average mean temperature and daily average mean absolute humidity. The global seasonal patterns of RSV provided important information for optimizing interventions against RSV infection.

Comparison of a static cohort model and dynamic transmission model for respiratory syncytial virus intervention programs for infants in England and Wales

BACKGROUND

A recent study comparing results of multiple cost-effectiveness analyses (CEAs) in a hypothetical population found that monoclonal antibody (mAb) immunoprophylaxis for respiratory syncytial virus (RSV) in infants averted fewer medically attended cases when estimated using dynamic transmission models (DTMs) versus static cohort models (SCMs). We aimed to investigate whether model calibration or parameterization could be the primary driver of inconsistencies between SCM and DTM predictions.

METHODS

A recently published DTM evaluating the CEA of infant mAb immunoprophylaxis in England and Wales (EW) was selected as the reference model. We adapted our previously published SCM for US infants to EW by utilizing the same data sources used by the DTM. Both models parameterized mAb efficacy from a randomized clinical trial (RCT) that estimated an average efficacy of 74.5% against all medically attended RSV episodes and 62.1% against RSV hospitalizations. To align model assumptions, we modified the SCM to incorporate waning efficacy. Since the estimated indirect effects from the DTM were small (i.e., approximately 100-fold smaller in magnitude than direct effects), we hypothesized that alignment of model parameters should result in alignment of model predictions. Outputs for model comparison comprised averted hospitalizations and averted GP visits, estimated for seasonal (S) and seasonal-with-catchup (SC) immunization strategies.

RESULTS

When we aligned the SCM intervention parameters to DTM intervention parameters, significantly more averted hospitalizations were predicted by the SCM (S: 32.3%; SC: 51.3%) than the DTM (S: 17.8%; SC: 28.6%). The SCM most closely replicated the DTM results when the initial efficacy of the mAb intervention was 62.1%, leading to an average efficacy of 39.3%. Under this parameterization the SCM predicted 17.4% (S) and 27.7% (SC) averted hospitalizations. Results were similar for averted GP visits.

CONCLUSIONS

Parameterization of the RSV mAb intervention efficacy is a plausible primary driver of differences between SCM versus DTM model predictions.

Respiratory Syncytial Virus-Associated Hospitalizations in Children: A 10-Year Population-Based Analysis in Finland, 2008-2018

BACKGROUND

The risk of respiratory syncytial virus (RSV) hospitalization is highest during the first months of life, but few studies have assessed the population-based rates of hospitalization in monthly age groups of infants.

METHODS

We determined the average population-based rates of hospitalization with virologically confirmed RSV infections in children ≤15 years of age admitted during the 10-year period of 2008-2018. Testing for RSV was routine in all children hospitalized with respiratory infections, and all RSV-positive children admitted at any time during the study period were included in the analyses.

RESULTS

The annual population-based rate of RSV hospitalization was highest in infants 1 month of age (52.0 per 1000 children; 95% CI, 45.2-59.7), followed by infants <1 month of age (34.8 per 1000; 95% CI, 29.2-41.1) and those 2 months of age (32.2 per 1000; 95% CI, 26.9-38.4). In cumulative age groups, the rate of hospitalization was 39.7 per 1000 (95% CI, 36.2-43.4) among infants <3 months of age, 26.8 per 1000 (95% CI, 24.8-29.0) in infants aged <6 months, and 15.8 per 1000 (95% CI, 14.7-17.0) in those <12 months of age.

CONCLUSION

In monthly age groups of infants, the incidence rates of virologically confirmed RSV hospitalization in all infants up to 3 months of age were substantially higher than those reported in earlier studies. These data may be important for improving the estimates of the cost-effectiveness of various interventions to reduce the burden of RSV in young infants.

The role of real-world evidence for regulatory and public health decision-making for Accelerated Vaccine Deployment- a meeting report

The COVID-19 pandemic underscored the need for rapid evidence generation to inform public health decisions beyond the limitations of conventional clinical trials. This report summarises presentations and discussions from a conference on the role of Real-World Evidence (RWE) in expediting vaccine deployment. Attended by regulatory bodies, public health entities, and industry experts, the gathering was a collaborative exchange of experiences and recommendations for leveraging RWE for vaccine deployment. RWE proved instrumental in refining decision-making processes to optimise dosing regimens, enhance guidance on target populations, and steer vaccination strategies against emerging variants. Participants felt that RWE was successfully integrated into lifecycle management, encompassing boosters and safety considerations. However, challenges emerged, prompting a call for improvements in data quality, standardisation, and availability, acknowledging the variability and potential inaccuracies in data across diverse healthcare systems. Regulatory transparency should also be prioritised to foster public trust, and improved collaborations with governments are needed to streamline data collection and navigate data privacy regulations. Moreover, building and sustaining resources, expertise, and infrastructure in LMICs emerged as imperative for RWE-generating capabilities. Continued stakeholder collaboration and securing adequate funding emerged as vital pillars for advancing the use of RWE in shaping responsive and effective public health strategies.

Cost-effectiveness analysis of nirsevimab and maternal RSVpreF vaccine strategies for prevention of Respiratory Syncytial Virus disease among infants in Canada: a simulation study

Background

The cost-effectiveness of immunisation strategies with a long-acting monoclonal antibody (nirsevimab) and/or a protein-based maternal vaccine (RSVpreF) for protecting infants from Respiratory Syncytial Virus (RSV)-associated illness has not been previously determined for Canada. We estimated the health benefits and cost-effectiveness of nirsevimab for immunising the entire birth cohort, regardless of gestational age or other risk factors. Additionally, we evaluated the health benefits and cost-effectiveness of a combined strategy of year-round vaccination of pregnant women with RSVpreF and immunisation of infants at high risk, including those born preterm or with chronic conditions, with nirsevimab during the RSV season.

Methods

We developed a discrete-event simulation model, parameterized with the data on medically-attended RSV infections among infants under one year of age from 2010 to 2019, including outpatient care, hospitalisations, and deaths. Intervention scenarios targeting twelve monthly birth cohorts and pregnant women, reflecting the 2021 census data for Ontario, Canada were evaluated over a follow-up time horizon of one year from birth. Taking into account the costs (in 2023 Canadian dollars) associated with RSV-related outcomes, we calculated the net monetary benefit using the quality-adjusted life-year (QALY) gained. Further, we determined the range of price-per-dose (PPD) for nirsevimab and RSVpreF within which the program was cost-effective. Cost-effectiveness analyses were conducted from both healthcare and societal perspectives.

Findings

Using a willingness-to-pay of CAD$50,000 per QALY gained, we found that immunising the entire birth cohort with nirsevimab would be cost-effective from a societal perspective for a PPD of up to $290, with an annual budget impact of $83,978 for 1113 infants per 100,000 population. An alternative, combined strategy of vaccinating pregnant women and immunising only infants at high risk of severe disease would lead to a lower budget impact of $49,473 per 100,000 population with a PPD of $290 and $195 for nirsevimab and RSVpreF vaccine, respectively. This combined strategy would reduce infant mortality by 76%-85%, comparable to a 78% reduction achieved through a nirsevimab-only program of the entire birth cohort. The PPD for cost-effective programs with nirsevimab was sensitive to the target population among infants.

Interpretation

Passive immunisation of infants under 6 months of age with nirsevimab and vaccination of pregnant women with RSVpreF could be a cost-effective strategy for protecting infants during their first RSV season.

Funding

This study was supported by the Canadian Immunisation Research Network (CIRN) and the Canadian Institutes of Health Research (CIHR). Seyed M. Moghadas acknowledges support from the Natural Sciences and Engineering Research Council of Canada (MfPH and Discovery grants). Alison P. Galvani acknowledges support from the The Notsew Orm Sands Foundation.

Pediatric RSV-Associated Hospitalizations Before and During the COVID-19 Pandemic

Importance

Respiratory syncytial virus (RSV) is a leading cause of pediatric hospitalizations.

Objective

To describe the epidemiology and burden of RSV-associated hospitalizations among children and adolescents in Canadian tertiary pediatric hospitals from 2017 to 2022, including changes during the COVID-19 pandemic.

Design, Setting, and Participants

This cross-sectional study was conducted during 5 RSV seasons (2017-2018 to 2021-2022) at 13 pediatric tertiary care centers from the Canadian Immunization Monitoring Program Active (IMPACT) program. Hospitalized children and adolescents aged 0 to 16 years with laboratory-confirmed RSV infection were included.

Main Outcomes and Measures

The proportion of all-cause admissions associated with RSV and counts and proportions of RSV hospitalizations with intensive care unit (ICU) admission, prolonged stay (≥7 days), and in-hospital mortality were calculated overall and by season, age group, and region. Seasonality was described using epidemic curves. RSV hospitalizations for 2021-2022 were compared with those in the prepandemic period of 2017-2018 through 2019-2020. Bonferroni corrections were applied to P values to adjust for multiple statistical comparisons.

Results

Among 11 014 RSV-associated hospitalizations in children and adolescents (6035 hospitalizations among male patients [54.8%]; 5488 hospitalizations among patients aged <6 months [49.8%]), 2594 hospitalizations (23.6%) had admission to the ICU, of which 1576 hospitalizations (60.8%) were among children aged less than 6 months. The median (IQR) hospital stay was 4 (2-6) days. The mean (SD) number of RSV-associated hospitalizations during prepandemic seasons was 2522 (88.8) hospitalizations. There were 58 hospitalizations reported in 2020-2021, followed by 3170 hospitalizations in 2021-2022. The proportion of all-cause hospitalizations associated with RSV increased from a mean of 3.2% (95% CI, 3.1%-3.3%) before the pandemic to 4.5% (95% CI, 4.3%-4.6%) in 2021-2022 (difference, 1.3 percentage points; 95% CI, 1.1-1.5 percentage points; corrected P < .001). A significant increase in RSV-associated hospitalizations was found in 2021-2022 for 3 provinces (difference range, 2.5 percentage points; 95% CI, 1.4-3.6 percentage points for Quebec to 2.9 percentage points; 95% CI, 1.4-3.5 percentage points for Alberta; all corrected P < .001). Age, sex, ICU admission, prolonged length of stay, and case fatality rate did not change in 2021-2022 compared with the prepandemic period. Interregional differences in RSV seasonality were accentuated in 2021-2022, with peaks for 1 province in October, 4 provinces in December, and 3 provinces in April, or May.

Conclusions and Relevance

This study found that the burden of RSV-associated hospitalizations in Canadian pediatric hospitals was substantial, particularly among infants aged less than 6 months, and RSV hospitalizations increased in 2021-2022 compared with the prepandemic period, while severity of illness remained similar. These findings suggest that RSV preventive strategies for infants aged less than 6 months would be associated with decreased RSV disease burden in children.

Nirsevimab for the prevention of respiratory syncytial virus disease in children. Statement of the Spanish Society of Paediatric Infectious Disease (SEIP)

INTRODUCTION

Nirsevimab, a monoclonal antibody for the prevention of disease caused by respiratory syncytial virus (RSV), has recently been approved for use in Europe and Spain.

OBJECTIVES

To provide recommendations for the administration of nirsevimab for prevention of RSV disease.

METHODS

The approach chosen to develop these recommendations involved a critical review of the literature and the use of the Delphi and GRADE methods. An expert group was formed. The group engaged in three rounds to define the questions, express support or opposition, grade recommendations and establish the agreement or disagreement with the conclusions.

RESULTS

In the general neonatal population, routine administration of nirsevimab is recommended to reduce the frequency of illness and hospitalisation for bronchiolitis and RSV lower respiratory tract infection. Nirsevimab is recommended for all infants born in high-incidence RSV season and infants aged less than 6 months at the season onset. In infants born preterm between 29 and 35 weeks of gestation, with haemodynamically significant heart disease or with chronic lung disease, routine administration of nirsevimab is recommended to reduce the incidence of disease and hospitalisation due to bronchiolitis and RSV lower respiratory tract infection. In patients in whom palivizumab is currently indicated, its substitution by nirsevimab is recommended to reduce the burden of bronchiolitis.

CONCLUSIONS

Routine administration of nirsevimab to all infants aged less than 6 months born during the RSV season or aged less than 6 months at the start of the winter season is recommended to reduce the burden of disease and the frequency of hospitalization due to bronchiolitis.