Early Safety Findings Among Persons Aged ≥60 Years Who Received a Respiratory Syncytial Virus Vaccine - United States, May 3, 2023-April 14, 2024

Respiratory syncytial virus vaccination in older adults and patients with chronic disorders: A position paper from the Portuguese Society of Pulmonology, the Portuguese Association of General and Family Medicine, the Portuguese Society of Cardiology, the Portuguese Society of Infectious Diseases and Clinical Microbiology, the Portuguese Society of Endocrinology, Diabetes and Metabolism, and the Portuguese Society of Internal Medicine

BACKGROUND

Respiratory syncytial virus (RSV) is an important cause of lower respiratory tract infection, hospitalisation and death in adults.

METHODS

Based on evidence regarding the impact of RSV on adult populations at risk for severe infection and the efficacy and safety of RSV vaccines, the Portuguese Society of Pulmonology, the Portuguese Association of General and Family Medicine, the Portuguese Society of Cardiology, the Portuguese Society of Infectious Diseases and Clinical Microbiology, the Portuguese Society of Endocrinology, Diabetes and Metabolism, and the Portuguese Society of Internal Medicine endorses this position paper with recommendations to prevent RSV-associated disease and its complications in adults through vaccination.

CONCLUSION

The RSV vaccine is recommended for people aged ≥50 years with risk factors (chronic obstructive pulmonary disease, asthma, heart failure, coronary artery disease, diabetes, chronic kidney disease, chronic liver disease, immunocompromise, frailty, dementia, and residence in a nursing home) and all persons aged ≥60 years. If it cannot be made available to this population, then the vaccine should be prioritised for individuals aged ≥75 years and those aged ≥50 years with risk factors. The vaccine should preferably be given between September and November and can be co-administered with the influenza vaccine. Ongoing studies on RSV vaccines may justify extending these recommendations in the future.

Respiratory syncytial virus pulmonary infections in adults - disease burden and prevention

PURPOSE OF REVIEW

We highlight the evolving understanding of the burden of respiratory syncytial virus (RSV) in older adults and recent data on the three new vaccines.

RECENT FINDINGS

As well as a greater recognition of the amount of RSV infection in adults, and especially over 60 years of age, there has been a significant amount of study detailing the postacute burden including excess cardiovascular disease and loss of physical and cognitive functioning. Three new RSV vaccines now have published data for two seasons, and while direct comparison is not possible due to differences in the timing, methodology and populations studies, all show good efficacy with no serious side effects of concern.

SUMMARY

RSV causes a substantial amount of morbidity and mortality in older adults with both acute and longer term impacts. With effective vaccines now available clinicians should be advocating with their patients to prevent RSV infection.

Respiratory syncytial virus infections in adults

Respiratory syncytial virus (RSV) infections as an important cause of acute respiratory illness (ARI) and exacerbation of chronic lung disease in adults especially affect older adults, adults with immunosuppression, and adults with chronic disease, particularly pulmonary or cardiac disease, who may develop more severe complications. A more accurate determination of the burden of RSV infection in the adult population would improve the approach to infection, especially considering the growth of the older adult population in the world and, above all, that there are currently three approved vaccines aimed at the adult population that could have an effect on the prevention of RSV infection. This review article reviews the most relevant and novel scientific evidence on the epidemiology, diagnosis, treatment and prevention of RSV infection in the adult population.

Recent advances in the prevention and treatment of respiratory syncytial virus disease

Respiratory syncytial virus (RSV) is associated with considerable healthcare burden; as such, prevention and treatment of RSV have long been considered a priority. Historic failures in RSV vaccine development had slowed the research field. However, the discovery of the conformational change in the RSV fusion protein (F) has led to considerable advancements in the field. The RSV pharmaceutical landscape has drastically changed in recent years with successful trials of both vaccines and second-generation mAbs leading to licensing and roll-out of these agents in several countries. RSV preventative and therapeutic measures will likely have a significant impact on RSV-related morbidity and mortality. However, there are still gaps in the protection that these immunizations offer that should be addressed. Many unanswered questions about RSV infection dynamics and subsequent disease should be a focus of ongoing research. This review discusses the currently licensed RSV pharmaceuticals and others that have recently progressed to clinical trials.

Adult vaccinations against respiratory infections

INTRODUCTION

Lower respiratory infections have a huge impact on global health, especially in older individuals, immunocompromised people, and those with chronic comorbidities. The COVID-19 pandemic highlights the importance of vaccination. However, there are lower rates of vaccination in the adult population that are commonly due to a missed opportunity to vaccinate. Vaccination offers the best strategy to prevent hospitalization, complications, and death caused by lower respiratory infections.

AREAS COVERED

In this review, the authors provide an overview of the vaccines for lower respiratory infections in the adult population. The review highlights the available data about the impact of vaccines on preventing respiratory infections, focusing on the pneumococcal vaccine, influenza vaccine, COVID-19 vaccines, and respiratory syncytial virus (RSV) vaccines. The authors discuss the currently available scientific evidence on the role of vaccines against respiratory infections. Finally, the authors review the current recommendations for vaccines in the adult population.

EXPERT OPINION

Scientific evidence on the effectiveness of vaccines against respiratory infections is important. An efficient implementation of adult immunization strategies will provide an opportunity to decrease the global burden of lower respiratory infections. Recognizing the existing vaccines and their recommendations for the adult population is essential to achieve a high vaccination rate in the population.

Development, Current Status, and Remaining Challenges for Respiratory Syncytial Virus Vaccines

Respiratory syncytial virus (RSV) causes significant morbidity and mortality, especially in young children and the elderly. RSV vaccine development puzzled vaccinologists for years. Safety concerns of initial formulations, the lack of an absolute correlate of protection, and the need for selecting appropriate virus attenuation and antigen-adjuvant combinations contributed to delayed vaccine production. The recent stabilization of the RSV-F glycoprotein in the prefusion (preF) conformation that constitutes the primary target of RSV-neutralizing antibodies was key for efficient vaccine design. Two protein subunit vaccines (GSK's Arexvy and Pfizer's Abrysvo) and one mRNA RSV vaccine (Moderna's mRESVIA) are now available. This article aims to provide a comparative overview of the safety and efficacy of novel RSV vaccines that are approved for the prevention of RSV-lower respiratory tract disease (LRTD) in adults 60 years of age and older, with updated recommendations calling for the expansion of vaccination to all adults at increased risk for severe RSV disease. Abrysvo is the only vaccine indicated for use in pregnancy to prevent RSV-LRTD in infants from birth to 6 months of age. We provide a comparative assessment of the efficacy of approved RSV vaccines over a maximum of three seasons, summarizing currently available data. We conclude that despite the decreasing vaccine efficacy over time, which should be anticipated for a virus that is characterized by short-term immunity, efficacy was clinically meaningful over placebo. The increased risk of Guillain-Barré syndrome post vaccination with Abrysvo or Arexvy, which prompted the FDA to require the inclusion of such warnings in the prescribing information of these two RSV vaccines, should be prioritized and investigated thoroughly. Furthermore, ongoing vaccine surveillance and further evaluation, particularly among immunocompromised patients, frail elderly subjects, and young infants that were under- or not represented in pivotal clinical trials, are necessary. As in the success story of combined pediatric vaccines, combination vaccines, conferring protection against several respiratory illnesses in one dose, could help improve vaccine acceptance and coverage rates in older adults.

The recent landscape of RSV vaccine research

Respiratory syncytial virus (RSV) causes a significant burden of acute respiratory illness across all ages, particularly for infants and older adults. Infants, especially those born prematurely or with underlying health conditions, face a high risk of severe RSV-related lower respiratory tract infections (LRTIs). Globally, RSV contributes to millions of LRTI cases annually, with a disproportionate burden in low- and middle-income countries (LMICs). The RSV virion outer capsule contains glycoproteins G and F which are essential for viral entry into respiratory epithelial cells and represent key targets for therapeutics development. The F-glycoprotein has several highly conserved antigenic sites that have proven useful targets for the development of monoclonal antibodies (mAbs) against RSV. Historically, prevention in infants was limited to the mAb palivizumab, which, despite its efficacy, was costly and inaccessible in many regions. Recent advancements include nirsevimab, a long-acting mAb that has shown substantial efficacy in reducing medically attended RSV-related disease in infants, in phase III clinical trials, early regional and national real-world data. In addition, three new vaccines have been approved: two protein subunit vaccines and a messenger RNA vaccine. The vaccines are all licenced for use in older adults, with one also approved as a maternal vaccine. Promising candidates in development include the mAb clesrovimab, which has an extended half-life and high levels in the nasal epithelial lining and high safety and efficacy profiles in late-stage trials. There are also a wide range of vaccine candidates currently in late-stage clinical trials. These developments signify a major advancement in RSV prevention strategies, offering improved protection for high-risk populations. With the ongoing rollout of the recently licenced vaccines and mAbs internationally, the landscape of RSV care is rapidly changing. We also must ensure these advances reach those in LMICs who need these therapies most.

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.

Respiratory Syncytial Virus: A WAidid Consensus Document on New Preventive Options

Background/Objectives: Respiratory syncytial virus (RSV) is a leading cause of respiratory infections, particularly affecting young infants, older adults, and individuals with comorbidities. Methods: This document, developed as a consensus by an international group of experts affiliated with the World Association of Infectious Diseases and Immunological Disorders (WAidid), focuses on recent advancements in RSV prevention, highlighting the introduction of monoclonal antibodies (mAbs) and vaccines. Results: Historically, RSV treatment options were limited to supportive care and the monoclonal antibody palivizumab, which required multiple doses. Recent innovations have led to the development of long-acting mAbs, such as nirsevimab, which provide season-long protection with a single dose. Nirsevimab has shown high efficacy in preventing severe RSV-related lower respiratory tract infections (LRTIs) in infants, reducing hospitalizations and ICU admissions. Additionally, new vaccines, such as RSVpreF and RSVpreF3, target older adults and have demonstrated significant efficacy in preventing LRTIs in clinical trials. Maternal vaccination strategies also show promise in providing passive immunity to newborns, protecting them during the most vulnerable early months of life. This document further discusses the global burden of RSV, its economic impact, and the challenges of implementing these preventative strategies in different healthcare settings. Conclusions: The evidence supports the integration of both passive (mAbs) and active (vaccines) immunization approaches as effective tools to mitigate the public health impact of RSV. The combined use of these interventions could substantially reduce RSV-related morbidity and mortality across various age groups and populations, emphasizing the importance of widespread immunization efforts.

Effectiveness and efficiency of immunisation strategies to prevent RSV among infants and older adults in Germany: a modelling study

BACKGROUND

Recently, several novel RSV immunisation products that protect infants and older adults against RSV disease have been licensed in Europe. We estimated the effectiveness and efficiency of introducing these RSV immunisation strategies in Germany.

METHODS

We used a Bayesian framework to fit a deterministic age-structured dynamic transmission model of RSV to sentinel surveillance and RSV-specific hospitalisation data in Germany from 2015 to 2019. The calibrated model was used to evaluate different RSV intervention strategies over 5 years: long-acting, single-dose monoclonal antibodies (mAbs) in high-risk infants aged 1-5 months; long-acting mAbs in all infants aged 1-5 months; seasonal vaccination of pregnant women and one-time seasonal vaccination of older adults (75 + /65 + /55 + years). We performed sensitivity analysis on vaccine uptake, seasonal vs. year-round maternal vaccination, and the effect of under-ascertainment for older adults.

RESULTS

The model was able to match the various RSV datasets. Replacing the current short-acting mAB for high-risk infants with long-acting mAbs prevented 1.1% of RSV-specific hospitalisations in infants per year at the same uptake. Expanding the long-acting mAB programme to all infants prevented 39.3% of infant hospitalisations per year. Maternal vaccination required a larger number to be immunised to prevent one additional hospitalisation than a long-acting mAB for the same uptake. Vaccination of adults older than 75 years at an uptake of 40% in addition to Nirsevimab in all infants prevented an additional 4.5% of all RSV hospitalisations over 5 years, with substantial uncertainty in the correction for under-ascertainment of the RSV burden.

CONCLUSIONS

Immunisation has the potential to reduce the RSV disease burden in Germany.