Respiratory Syncytial Virus Vaccine Research Articles

The efficacy of vaccination against respiratory syncytial virus across priority population subgroups

Abstract Background Respiratory syncytial virus (RSV) has recently become a vaccine-preventable disease as two vaccines have been approved for use and a third one is likely to become available by the end of the year. National Immunization Technical Advisory Groups as well as scientific societies across the world have issued recommendations on RSV vaccination that differ in respect to the identification of the target group. The latter has been identified in respect to age or underlying medical conditions mostly according to epidemiological data. In order to strengthen the evidence basis for future decisions, we performed a stratified meta-analysis of efficacy data considering all the three RSV vaccines currently or soon available. Methods We searched Randomized Controlled Trials (RCTs) assessing the efficacy of RSV vaccines in terms of reduction of RSV-related Lower Respiratory Tract Infection (LRTI). The research was conducted on PubMed and clinicaltrial.gov. The extraction of relevant data was stratified by pre-defined age groups (60-69, 70-79, 80+) and presence of underlying conditions increasing the risk for RSV. Results Three RCTs, one for each of the three vaccines, were considered for the quantitative analysis. Considering the overall 60+ population, the efficacy of RSV vaccines was 78% (95%CI 76-86%) in preventing LRTI. Considering the different age groups (60-69, 70-79, 80+), efficacy was respectively 72% (95%CI 53-84%), 90% (95%CI 66-97%) and 57% (95%CI 0-93%). The efficacy in healthy people and those with at least one underlying condition was similar, namely 77% (95%CI 60-87%) and 78% (95%CI 50-90%). Conclusions The available evidence shows the efficacy of RSV vaccines in reducing LRTI with no differences across different priority groups. Further studies may contribute to better understanding if the efficacy may change according to individual characteristics, that could be highly relevant in the decision-making process. Key messages • The available evidence from RCTs shows the efficacy of RSV vaccines in reducing LRTI with no differences across different priority groups. • National recommendations on RSV vaccination can be further informed for future studies investigating RSV vaccines efficacy across different subgroups.

New advances in RSV: Is prevention attainable?

Respiratory syncytial virus (RSV) is a major cause of lower respiratory tract infection (LRTI), hospitalization, and mortality in infants and young children globally. The greatest burden of severe disease and mortality occurs in low-middle income countries (LMICs), with large and vulnerable childhood populations. The highest rates of RSV-hospitalization occur in healthy-term infants under 3 months of age. Preterm infants, children with chronic lung disease of prematurity, Down's syndrome, congenital heart disease, or immunodeficiency also have a higher risk of severe RSV-LRTI. Early-life RSV-LRTI has also been associated with chronic sequelae, including recurrent LRTI, recurrent wheezing, asthma, and lung function impairment. A RSV pre-fusion (F) maternal vaccine and long-acting monoclonal antibody (nirsevimab) have been licensed for the prevention of RSV-LRTI in infants and young children. Studies show high efficacy and effectiveness particularly for preventing severe RSV-LRTI. Maternal RSV vaccine given at 24-36 weeks of pregnancy was effective in preventing RSV medically attended LRTI and severe RSV-LRTI through 6 months after birth in a phase 3 study conducted in 18 countries over two RSV seasons. Vaccination was safe with no significant difference in adverse events between infants born to mothers who received RSV preF vaccine compared to placebo. A numerical imbalance in preterm births that occurred predominantly in South Africa, unrelated to vaccine timing or gestational age at vaccination and unassociated with mortality, coincided with COVID-19 delta and omicron waves. Nirsevimab, given as a single dose prior or during the RSV season, had high efficacy in preventing RSV-LRTI hospitalization in infants in preterm and in full-term infants, as well as in young children with underlying conditions through 150 days post administration in phase 2 and 3 trials. High effectiveness against hospitalization or severe disease in infants and in at-risk children up to 2 years of age has also been reported in several countries where implementation has occurred. RSV-LRTI is now a preventable disease in infants and young children. Rapid implementation of these highly effective interventions has occurred in many high-income countries, but access remains very limited in LMICs. Access to such RSV preventive interventions is urgently needed for all children to strengthen child health and promote global equity.

A multivalent RSV vaccine based on the modified vaccinia Ankara vector shows moderate protection against disease caused by RSV in older adults in a phase 3 clinical study

Respiratory syncytial virus (RSV) causes a significant disease burden in older adults. The live recombinant vaccine based on a nonreplicating modified vaccinia Ankara (MVA-BN) poxvirus, MVA-BN-RSV, encoding for multiple proteins of RSV subtypes A and B, was assessed for efficacy against respiratory disease caused by RSV.Adults aged ≥60 years, with or without underlying chronic conditions, were enrolled and randomized in a 1:1 ratio to receive a single dose of vaccine or placebo and were followed for disease caused by RSV infection during the 2022–2023 season. The 2 primary endpoints were RSV-associated lower respiratory tract disease (LRTD) with ≥3 and ≥ 2 symptoms; acute respiratory disease (ARD) was a key secondary endpoint. The humoral RSV-specific immune response was assessed at baseline and 14 days post-vaccination. Safety was evaluated by collection of solicited adverse events (AEs) and unsolicited AEs for 7 and 28 days post-vaccination respectively, and SAEs for the entire study period.In total, 18,348 participants were included in the final efficacy and safety analyses. Vaccine efficacy was 42.9 % (95 % CI: −16.1; 71.9) against RSV-associated LRTD with ≥3 symptoms, 59.0 % (95 % CI: 34.7; 74.3) against LRTD with ≥2 symptoms, and 48.8 % (95 % CI: 25.8; 64.7) against ARD. The primary objective was not met for LRTD with ≥3 symptoms since the lower bound of the 95 % CI was below 20 %, the prespecified success criterion. The vaccine-elicited immune response showed mean fold-increases of 1.7 for RSV A and B neutralizing antibodies and 2.9 and 4.3 for RSV-specific IgG and IgA, respectively. The vaccine displayed mild to moderate reactogenicity, and no safety concerns were identified.MVA-BN-RSV induced suboptimal protection against RSV-associated LRTD, likely due to suboptimal neutralizing antibody response. The vaccine had an acceptable safety profile and confirmed immunogenicity, overall showing promise for MVA-BN-vectored constructs targeting other diseases.Trial Registration:Clinicaltrials.gov Identifier NCT05238025 (Registered February 14, 2022).

The impact of viral respiratory infection on surgical outcome of cavopulmonary shunt.

Undetected respiratory infections may adversely affect the intrapulmonary resistance after Stage 2 or Stage 3 Fontan palliation. A few studies describe a higher risk for viral pneumonia during respiratory virus season, but none of them have focused on the effect of symptomatic viral pneumonia on in-hospital clinical course after bidirectional Glenn shunt. We analysed 77 patients who underwent bidirectional Glenn shunt surgery. Six patients were detected with pneumonia and proof of viral ribonucleic acid in tracheal mucus in the very early postoperative time. We compared them retrospectively to the remaining 71 patients regarding preoperative inflammatory signs, mortality, paediatric ICU length of stay, and ventilation time. The infection rate was not seasonal dependent. Ventilation time was significantly elongated in the pneumonia group (558 h ± 634 vs. 8.7 h ± 1.9; p < 0.0001) and so was the paediatric ICU length of stay (29 days ± 26 vs. 3 days±1; p = 0.007). Significantly more patients in the pneumonia group required extracorporeal cardiac life support postoperatively. The mortality was significantly increased in patients with pneumonia. Even subclinical viral pneumonia may cause ventilation-to-perfusion mismatch by raising intrapulmonary resistance. Recorded parameters of postoperative paediatric ICU therapy showed a significant impact of a viral pneumonia on patients after bidirectional Glenn shunt. The respiratory syncytial virus vaccination does not protect these patients from infection with other respiratory viruses. The focus should be put on preoperative diagnosis of pulmonary infections in the vulnerable group of patients with univentricular hearts.

Respiratory syncytial virus (RSV) vaccine effectiveness against RSV-associated hospitalisations and emergency department encounters among adults aged 60 years and older in the USA, October, 2023, to March, 2024: a test-negative design analysis

Respiratory syncytial virus vaccines first recommended for use during 2023 were efficacious against lower respiratory tract disease in clinical trials. Limited real-world data regarding respiratory syncytial virus vaccine effectiveness are available. To inform vaccine policy and address gaps in evidence from the clinical trials, we aimed to assess the effectiveness against respiratory syncytial virus-associated hospitalisations and emergency department encounters among adults aged at least 60 years. We conducted a test-negative design analysis in an electronic health records-based network in eight states in the USA, including hospitalisations and emergency department encounters with respiratory syncytial virus-like illness among adults aged at least 60 years who underwent respiratory syncytial virus testing from Oct 1, 2023, to March 31, 2024. Respiratory syncytial virus vaccination status at the time of the encounter was derived from electronic health record documentation, state and city immunisation registries, and, for some sites, medical claims. Vaccine effectiveness was estimated by immunocompromise status, comparing the odds of vaccination among respiratory syncytial virus-positive case patients and respiratory syncytial virus-negative control patients, and adjusting for age, race and ethnicity, sex, calendar day, social vulnerability index, number of underlying non-respiratory medical conditions, presence of respiratory underlying medical conditions, and geographical region. Among 28 271 hospitalisations for respiratory syncytial virus-like illness among adults aged at least 60 years without immunocompromising conditions, vaccine effectiveness was 80% (95% CI 71-85) against respiratory syncytial virus-associated hospitalisations, and vaccine effectiveness was 81% (52-92) against respiratory syncytial virus-associated critical illness (ICU admission or death, or both). Among 8435 hospitalisations for respiratory syncytial virus-like illness among adults with immunocompromising conditions, vaccine effectiveness was 73% (48-85) against associated hospitalisation. Among 36 521 emergency department encounters for respiratory syncytial virus-like illness among adults aged at least 60 years without an immunocompromising condition, vaccine effectiveness was 77% (70-83) against respiratory syncytial virus-associated emergency department encounters. Vaccine effectiveness estimates were similar by age group and product type. Respiratory syncytial virus vaccination was effective in preventing respiratory syncytial virus-associated hospitalisations and emergency department encounters among adults aged at least 60 years in the USA during the 2023-24 respiratory syncytial virus season, which was the first season after respiratory syncytial virus vaccine was approved. The Centers for Disease Control and Prevention.

The Cumulative Variations of Respiratory Syncytial Virus Fusion Protein (F) in Ten Consecutive Years in China.

Variations in the fusion (F) protein of respiratory syncytial virus (RSV) with main antigenic sites I-V and Ø may affect the development of RSV vaccines and therapies. In the study, 30 respiratory specimens positive for RSV were randomly selected from children with acute lower respiratory infections (ALRI) in Beijing every year from 2012 to 2021 for F gene sequencing. Then, 300 F gene sequences and 508 uploaded to GenBank from China were subjected to phylogenetic analysis. The results indicated the nucleotide identities were 95.4-100% among 446 sequences of RSV A, and 96.3-100% among 362 of RSV B. The most common variant loci were N80K (100.00%) and R213S (97.76%) for site Ø, and V384I/T (98.43%) for site I among sequences of RSV A, and M152I (100.00%), I185V (100.00%), and L172Q/H (94.48%) for site V, and R202Q (99.45%) for site Ø among sequences of RSV B. N276S appears in 95.29% sequences of RSV A, while S276N and N262 I/S appear in 1.38% and 0.55% sequences of RSV B, respectively. No variation was found in all sequences at the binding sites of 14N4 and motavizumab. There were cumulative variations of the RSV F gene, especially at some binding sites of antigenic sites.

Induction of neutralizing antibody responses by AAV5-based vaccine for respiratory syncytial virus in mice.

Respiratory Syncytial Virus (RSV) is a significant cause of respiratory illnesses worldwide, particularly in infants and elderly individuals. Despite the burden RSV imposes, effective preventive measures are limited. The research application of adeno-associated virus (AAV) in vaccine platforms has been expanding, and its potential in prevention and treatment has garnered much attention. In this study, we explored the potential application of a recombinant adeno-associated virus 5 (rAAV5) vector-based RSV vaccine, focusing on the expression of the pre-fusion (Pre-F) protein structure. Through intramuscular immunization in mice. The immunogenicity of the vaccine was evaluated in Balb/c mice immunized intramuscularly and intranasal, respectively. The rAAV5-RSV-Fm vaccine demonstrated positive humoral and induced antibody titers against RSV strains A and B for up to 120 days post-immunization. Notably, intranasal administration also elicited protective antibodies. Characterization studies confirmed the ability of the vac-cine to express the Pre-F protein and its superior immunogenicity compared to that of full-length F protein. These findings underscore the potential application of rAAV5 vector platforms in RSV vaccine development and further investigation into their protective efficacy is warranted.

A new RSV vaccine (mResvia) for adults ≥60 years old.

The FDA has licensed mResvia (Moderna), an mRNA respiratory syncytial virus (RSV) vaccine, for prevention of lower respiratory tract disease (LRTD) caused by RSV in adults ≥60 years old. It is the first mRNA vaccine to be licensed in the US for this indication. Two recombinant RSV vaccines, Arexvy and Abrysvo, are also available for prevention of RSV LRTD.1 Arexvy is approved for use in adults ≥50 years old.2 Abrysvo is approved for use in adults ≥60 years old and in pregnant women to prevent RSV LRTD in their infants.

Update to: Study Pre-protocol for "BronchStart - The Impact of the COVID-19 Pandemic on the Timing, Age and Severity of Respiratory Syncytial Virus (RSV) Emergency Presentations; a Multi-Centre Prospective Observational Cohort Study".

In 2021 we launched the BronchStart study, which collected information on 17,899 presentations in children with serious respiratory tract infections following the release of lockdown restrictions. Our study informed the Joint Committee on Vaccination and Immunisation's decision to recommend the introduction maternal respiratory syncytial virus (RSV) vaccination, which was introduced in the United Kingdom in August/September 2024. We modified our original protocol to conduct a United Kingdom-wide assessment of maternal vaccination against RSV. We will conduct a multi-centre study, utilising the PERUKI network used in the original BronchStart study, to assess the effectiveness of maternal vaccination using a test-negative study design. We will gather detailed clinical information on children admitted with bronchiolitis in the post-RSV vaccination era, and understand possible reasons for incomplete vaccine uptake.

Prophylaxis of respiratory syncytial virus infection: current status and prospects for vaccine development

INTRODUCTION. Respiratory syncytial virus (RSV) is one of the most widespread pathogens that typically cause acute upper and lower respiratory tract infections in children and adults. Monoclonal antibody products have long been used for passive immunoprophylaxis in premature infants with bronchopulmonary dysplasia. However, vaccines have recently been licensed for the prophylactic immunisation of older adults with various risk factors for severe RSV infection (primarily, chronic cardiovascular and respiratory diseases and diabetes mellitus).AIM. This study aimed to review the current status of the development of vaccines for active immunisation against RSV infection, including the epidemiological rationale for their development, clinical trial results for licensed vaccines, recommendations for vaccination, and promising pipeline vaccines for RSV prevention.DISCUSSION. Initially hindered by the unique immunopathogenesis of RSV infection and the genetic hypervariability of RSV for a long time, attempts to develop an RSV vaccine succeeded when international researchers managed to identify a conservative neutralising antibody target capable of inducing specific immunity against RSV. This target, the RSV capsid protein stabilised in its prefusion (pre-F) conformation, can mediate viral entry into the cell following a conformational change. Several subunit vaccines based on recombinant pre-F proteins have successfully passed clinical trials and have been approved for the immunisation of older adults. In addition, one of these vaccines has been recommended for use during pregnancy to prevent RSV infection in newborns and infants. Currently, programmes are being implemented to develop novel RSV vaccines based on messenger RNA (mRNA) and non-replicating attenuated influenza vectors. This article examines and summarises the efficacy and safety parameters of two RSV vaccines approved in multiple countries around the world. Both vaccines have satisfactory safety profiles and comparable prophylactic efficacy parameters.CONCLUSIONS. Prelicensure clinical trials of novel RSV vaccines, including those being developed in the Russian Federation, should include prophylactic efficacy assessments in target patient populations. For vaccines approved by leading international regulators, clinical trials required for approval in the Russian Federation will be limited to bridging studies confirming the immunogenicity and safety of the vaccines.

Provider Guidance for the Prevention of Respiratory Syncytial Virus in Infants: Maternal Vaccination Versus Infant Monoclonal Antibody Treatment.

In 2023, the Food and Drug Administration approved 2 new products to reduce the risk of lower respiratory infections caused by respiratory syncytial virus (RSV) in infants: Beyfortus (nirsevimab; AstraZeneca/Sanofi), a single-dose monoclonal antibody for infant administration, and Abrysvo (bivalent RSVpreF vaccine; Pfizer), a single-dose maternal vaccination. We aimed to synthesize data from the literature and the leading professional organizations to provide guidance on RSV and strategies to reduce the risk of infant infection. This information will assist prenatal care clinicians in counseling their patients regarding the choice between maternal vaccination and the infant monoclonal antibody. A descriptive review of the guidelines from the Centers for Disease Control and Prevention, American College of Obstetrics and Gynecology (ACOG), American Academy of Pediatrics, Society for Maternal-Fetal Medicine, and the American Academy of Family Physicians. All 5 organizations recommend that RSV vaccination should be offered to all pregnant people during the RSV season (September-January in the continental United States). Infants younger than 8 months entering into their first RSV season born to those who did not receive maternal vaccination or received vaccination less than 14 days prior to birth should be offered monoclonal antibody administration. RSV vaccination and monoclonal antibodies have the potential to significantly reduce the burden of lower respiratory tract infections due to RSV in infants. Future studies should further evaluate the durability of protection and other strategies to further protect the infant, including cocooning and the role of breast milk in immunity.

Respiratory syncytial virus prevention is finally here: An overview of safety.

A number of respiratory syncytial virus (RSV) prevention products have recently been approved in Australia. These products focus on highest risk groups, aiming to prevent RSV disease in young infants and older adults. While not currently included in the National Immunisation Program (NIP), an RSV vaccine (Arexvy, GlaxoSmithKline [GSK]) isavailable privately for adults ≥60 years, and some Australian jurisdictions have commenced RSV monoclonal antibody (nirsevimab) programs for infants in 2024. This article summarises safety data regarding RSV prevention products approved in Australia, including vaccines for adults ≥60 years, maternal vaccines and monoclonal antibodies for infants. Clinical trial data found these products were largely well tolerated, with most local and systemic reactions being mild-moderate and short-lived. Proportions of serious adverse events were low. While very rare, potential safety signals being further assessed include risk of preterm birth following the maternal vaccine (Abrysvo, Pfizer) and Guillain-Barré syndrome (GBS) following RSV vaccines in older adults (Abrysvo and Arexvy). Close monitoring of these adverse events of special interest via post-licensure surveillance is underway.

S1048 Respiratory Syncytial Virus Vaccine is Associated With Better Outcomes in Inflammatory Bowel Disease Patients over 60 Years Old: A US Propensity-Matched Study

S1048 Respiratory Syncytial Virus Vaccine is Associated With Better Outcomes in Inflammatory Bowel Disease Patients over 60 Years Old: A US Propensity-Matched Study

Respiratory Syncytial Virus among People Living with HIV: Is There a Case for Rolling Out Prophylaxis? A Viewpoint Based on a Systematic Review.

Respiratory Syncytial Virus (RSV) is responsible for a considerable burden of respiratory disease among children and older adults. Several prophylactic strategies have recently been introduced. We review the available evidence on the interplay between RSV infection and HIV, looking at the specific role of RSV prophylactic strategies in individuals affected by or exposed to HIV. We conducted a systematic review on the association between HIV infection and RSV incidence and severity. We searched in PubMed/MEDLINE for clinical epidemiological studies covering outcomes such as RSV-associated illness, severity, and mortality in individuals affected by or exposed to HIV. A total of 36 studies met the inclusion criteria and were included, the majority conducted in sub-Saharan Africa. There was no compelling evidence suggesting a higher incidence of RSV illness among HIV-infected people. A higher risk of severe disease was consistent among both HIV-positive and HIV-exposed but uninfected (HEU) children. Case fatality rates were also higher for these groups. Evidence on a differing risk among adults was scarce. HIV-positive pregnant women should be given priority for recently approved RSV vaccination, for protection of their newborns. HIV-infected and HEU infants should be considered risk groups for nirsevimab prophylaxis in their first year of life and possibly beyond.

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.

Respiratory syncytial virus vaccination strategies for older Canadian adults: a cost-utility analysis.

Respiratory syncytial virus (RSV) vaccines could reduce disease burden and costs in older Canadian adults, but vaccination program cost-effectiveness is unknown. We evaluated the cost-effectiveness of different age cut-offs for RSV adult vaccination programs, with or without a focus on people with higher disease risk due to chronic medical conditions. We developed a static individual-based model of medically attended RSV disease to compare alternative age-, medical risk-, and age-plus medical risk-based vaccination policies. The model followed a multiage population of 100 000 people aged 50 years and older. Vaccine characteristics were based on RSV vaccines authorized in Canada as of May 2024, with vaccine protection assumed to last 2 years (or 3 years in scenario analyses). We calculated sequential incremental cost-effectiveness ratios in 2023 Canadian dollars per quality-adjusted life year (QALY) from the health-system and societal perspectives, discounted at 1.5%. Although all vaccination strategies averted medically attended RSV disease, universal age-based strategies were not an efficient use of resources compared with medical risk-based strategies. Vaccinating adults aged 70 years and older with 1 or more chronic medical condition was the optimal strategy for a cost-effectiveness threshold of $50 000 per QALY. Results were sensitive to assumptions about vaccine price, but medical risk-based approaches remained optimal compared with age-based strategies, even when vaccine prices were low. Findings were robust to a range of alternative assumptions. Vaccination programs for RSV in some groups of older Canadians with underlying medical conditions are likely cost-effective. These findings can inform the design of vaccination programs.

Respiratory syncytial virus vaccination in older adults.

Respiratory syncytial virus vaccination in older adults.

Global progress in clinical research on human respiratory syncytial virus vaccines.

Human respiratory syncytial virus (hRSV) not only affects newborns but also older adults, contributing to a substantial worldwide burden of disease. However, only three approved hRSV vaccines remain commercially available to date. The development of a safe, practical and broad-spectrum vaccine suitable for all age groups remains extremely challenging. Using five different approaches-live-attenuated, recombinant-vector, subunit, particle-based, and mRNA-nearly 30 hRSV vaccine candidates are currently conducting clinical trials worldwide; moreover, > 30 vaccines are under preclinical evaluation. This review presents a comprehensive overview of these hRSV vaccines along with prospects for the development of infectious disease vaccines in the post-COVID-19 pandemic era.

Acceptance of the Respiratory Syncytial Virus Vaccine in Pregnant Individuals

The respiratory syncytial virus (RSV) vaccine was officially offered to pregnant individuals in 2023–2024, with the purpose of providing immunity to infants and young children. We performed a retrospective review to determine the rate of offering the RSV vaccine and acceptance of the vaccine among patients between 32 0/7 and 36 6/7 weeks of gestation. A prospective survey was administered to examine barriers to RSV vaccination. We identified 206 patients, including 111 (53.8%) who were offered the vaccine and 95 (46.1%) who were not offered the vaccine. Of those who were offered the vaccine, 62 (55.9%) accepted and 49 (44.1%) declined. Individuals who declined had significantly higher rates of declining other vaccines in pregnancy (P&lt;.001). More than half of those who declined the RSV vaccine reported both accepting the RSV antibody for their newborn and plans of accepting the vaccine in subsequent pregnancies.

A multi-center study on genetic variations in the fusion protein of respiratory syncytial virus from children with Acute Lower Respiratory Tract Infections in China during 2017–2021

Respiratory syncytial virus (RSV) is a significant cause of acute lower respiratory tract infection (ALRTI) in children under five years of age. Between 2017 and 2021, 396 complete sequences of the RSV F gene were obtained from 500 RSV-positive throat swabs collected from ten hospitals across nine provinces in China. In addition, 151 sequences from China were sourced from GenBank and GISAID, making a total of 549 RSV F gene sequences subjected to analysis. Phylogenetic and genetic diversity analyses revealed that the RSV F genes circulating in China from 2017 to 2021 have remained relatively conserved, although some amino acids (AAs) have undergone changes. AA mutations with frequencies ≥ 10% were identified at six sites and the p27 region: V384I (site I), N276S (site II), R213S (site Ø), and K124N (p27) for RSV A; F45L (site I), M152I/L172Q/S173 ​L/I185V/K191R (site V), and R202Q/I206M/Q209R (site Ø) for RSV B. Comparing mutational frequencies in RSV-F before and after 2020 revealed minor changes for RSV A, while the K191R, I206M, and Q209R frequencies increased by over 10% in RSV B. Notably, the nirsevimab-resistant mutation, S211N in RSV B, increased in frequency from 0% to 1.15%. Both representative strains aligned with the predicted RSV-F structures of their respective prototypes exhibited similar conformations, with low root-mean-square deviation values. These results could provide foundational data from China for the development of RSV mAbs and vaccines.