---
title: "Immunogenicity and Safety of Single-Dose Adjuvanted RSVPreF3 Vaccine in Chinese Adults ≥60 — Phase"
id: "frontiers-in-immunology-17-immunogenicity-and-safety-of-a-single-dose-of-adjuvanted-rsvpref3-vaccine-in"
canonical_url: "https://medichelpline.com/clinical-feed/frontiers-in-immunology-17-immunogenicity-and-safety-of-a-single-dose-of-adjuvanted-rsvpref3-vaccine-in"
content_type: "clinical_feed_article"
specialty: "Infectious Disease"
source_name: "Frontiers in Immunology"
source_url: "https://www.frontiersin.org/articles/10.3389/fimmu.2026.1894773"
published_at: "2026-09-03T00:00:00.000Z"
evidence_level: "Journal Feed"
license: "CC-BY-NC-4.0 / Informational Use"
---
# Immunogenicity and Safety of Single-Dose Adjuvanted RSVPreF3 Vaccine in Chinese Adults ≥60 — Phase
## Provenance & Clinical Metadata
- **Canonical URL:** https://medichelpline.com/clinical-feed/frontiers-in-immunology-17-immunogenicity-and-safety-of-a-single-dose-of-adjuvanted-rsvpref3-vaccine-in
- **Specialty:** [Infectious Disease](https://medichelpline.com/clinical-feed/infectious-disease.md)
- **Primary Source:** Frontiers in Immunology
- **Source URL:** [Original Journal Publication](https://www.frontiersin.org/articles/10.3389/fimmu.2026.1894773)
- **Published At:** 2026-09-03T00:00:00.000Z
- **Evidence Rating:** Journal Feed
## Executive GIST (TL;DR)
- The source article title reports a phase 3 immunobridging trial evaluating a single dose of an **adjuvanted RSVPreF3** vaccine in adults aged 60 years and older in China. - The focus implied by the title is on both **immunogenicity** and **safety** of the vaccine in this older-adult population. - The design described in the title is a phase 3 immunobridging trial, which typically compares immune responses to a reference population or established correlate rather than clinical efficacy; the title indicates this approach. - The source material provided here did not include the article text, results, methods, participant numbers, endpoints, safety data, or statistical analyses. - Because the article body was not available in the provided source content, details such as immune-response magnitude, adverse event rates, study duration, inclusion/exclusion criteria, and conclusions were not reported and cannot be summarized. - For clinicians and researchers seeking actionable data (e.g., seroresponse rates, GMTs, solicited adverse events), the full peer-reviewed article should be consulted because those specifics are not present in the supplied source excerpt. - Key clinical terms from the title are **RSVPreF3**, **older adults (≥60 years)**, **single dose**, **adjuvanted vaccine**, and **phase 3 immunobridging trial**; these reflect the trial population, intervention, and study phase but not outcomes.
## Clinical Analysis & Structured Key Points
Frontiers | Immunogenicity and safety of a single dose of adjuvanted RSVPreF3 vaccine in adults ≥60 years of age in China: results from a phase 3 immunobridging trial ORIGINAL RESEARCH article Front. Immunol. , 03 September 2026 Sec. Vaccines and Molecular Therapeutics Volume 17 - 2026 | https://doi.org/10.3389/fimmu.2026.1894773 Published in Frontiers in Immunology Vaccines and Molecular Therapeutics 7 impact factor 11.3 citescore Editor & Reviewers Edited by K A Kalpit A Vora Reviewed by A A ANTONIOS ALIPRANTIS R R Radha Railkar Outline Figures and Tables Figure 1 View in article Figure 2 View in article Figure 3 View in article Figure 4 View in article Figure 5 View in article Figure 6 View in article Table 1 Participant characteristics at baseline (per protocol set at day 1). View in article Table 2 Safety summary (exposed set). View in article ORIGINAL RESEARCH article Front. Immunol. , 03 September 2026 Sec. Vaccines and Molecular Therapeutics Volume 17 - 2026 | https://doi.org/10.3389/fimmu.2026.1894773 Immunogenicity and safety of a single dose of adjuvanted RSVPreF3 vaccine in adults ≥60 years of age in China: results from a phase 3 immunobridging trial X G Xiang Guo 1 G N Guijun Ning 2 D B Dan Bi 3 S D Silvia Damaso 4 M D Monique Dodet 5 F H Fang Huang 1 X Z Xinji Zhang 3 F G Flavio Genco 4 H L Hongmei Lu 6 J Z Jingjing Zhao 7 L J Lili Jiang 8 X W Xiaoting Wu 9 X L Xiaojun Li 10 L Y Laibao Yang 11 N D Nancy Dezutter 4 X S Xiaodong Sun 1 * +8 more J H Jieqiong Hu 2 * On behalf of the RSV-021 Study Group 1. Shanghai Municipal Center for Disease Control and Prevention, Shanghai, China 2. GSK, Beijing, China 3. GSK, Shanghai, China 4. GSK, Wavre, Belgium 5. GSK, Rixensart, Belgium 6. Songjiang District Center for Disease Control and Prevention (Songjiang District Health Supervision Institute), Shanghai, China 7. Jiading District Center for Disease Control and Prevention (Jiading District Health Supervision Institute), Shanghai, China 8. Putuo District Center for Disease Control and Prevention (Putuo District Health Supervision Institute), Shanghai, China 9. Minhang District Center for Disease Control and Prevention (Minhang District Health Supervision Institute), Shanghai, China 10. Baoshan District Center for Disease Control and Prevention (Baoshan District Health Supervision Institute), Shanghai, China 11. Pudong New Area Center for Disease Control and Prevention (Pudong New Area Health Supervision Institute), Shanghai, China See more Article metrics View details Abstract Introduction: Respiratory syncytial virus (RSV) is an important cause of severe respiratory disease, yet no vaccine is available for older adults in China. This phase 3, randomized, partially blind immunobridging study (NCT06551181) compared a single dose of adjuvanted RSVPreF3 vaccine in ≥60-year-old Chinese adults with a non-Chinese population. Methods: Chinese participants were randomized 2:1 to receive adjuvanted RSVPreF3 (RSVPreF3_China group) or placebo (Placebo_China); participants from six additional countries (RSVPreF3_Overseas) received adjuvanted RSVPreF3. The primary objective was to demonstrate non-inferiority of humoral immune responses (RSV-A/RSV-B neutralizing titers) at 1 month post-vaccination in Chinese versus non-Chinese participants. Non-inferiority was met if the upper limit of the 95% confidence interval (CI) was ≤1.5 for the geometric mean titer (GMT) ratio (RSVPreF3_Overseas over RSVPreF3_China) and ≤10% for the seroresponse rate (SRR) difference (RSVPreF3_Overseas minus RSVPreF3_China). Reactogenicity and safety were also assessed. Results: Overall, 2620 participants were exposed (RSVPreF3_China: 1199; Placebo_China: 601; RSVPreF3_Overseas: 820); 2522 were included in the per protocol set at 1 month post-vaccination (RSVPreF3_China: 1175; Placebo_China: 590; RSVPreF3_Overseas: 757). Non-inferiority criteria were met for both RSV-A and RSV-B, with 95% CI upper limits of 1.20 and 1.10 for GMT ratios and 3.40% and 4.89% for SRR differences, respectively. Neutralizing titers increased at 1 month in vaccine recipients: RSV-A/RSV-B GMTs were 5523.2/8073.2 ED60 (mean geometric increase [MGI]=7.89/6.40) in the RSVPreF3_China group and 6604.5/8286.2 ED60 (MGI=8.04/6.57) in the RSVPreF3_Overseas group; GMTs remained above baseline at 6 months post-vaccination. Solicited events were more frequent in vaccine- than placebo-Chinese recipients but were mostly mild-to-moderate and transient. Pain (in 41.7% of participants in the RSVPreF3_China group versus 4.2% in the Placebo_China group) and fatigue (13.6% versus 3.2%) were the most frequently reported administration-site and systemic events, respectively. The incidence of unsolicited adverse events (reported in 11.8%–13.8% of participants across Chinese groups), serious adverse events (3.4%–6.5% across all groups), and potential immune-mediated diseases (0.2%–0.3% across all groups) was low and comparable between groups. Conclusion: A single dose of adjuvanted RSVPreF3 was immunogenic and well tolerated in Chinese adults aged ≥60 years, supporting the extrapolation of global efficacy and a favorable benefit-risk profile in this population. 1 Introduction Respiratory syncytial virus (RSV) remains a significant yet often underestimated cause of acute respiratory illness (ARI) and lower respiratory tract disease (LRTD) in young children ( 1 ), older adults ( 2 , 3 ), and individuals with certain underlying conditions ( 4 ). Older adults, in particular those with comorbidities, have a higher risk of developing severe RSV-associated illness, leading to high hospitalization and mortality rates. In China, RSV was identified as a leading cause of ARI between 2009 and 2019, accounting for 16.8% of ARI cases in individuals of all ages and 7.4% of those in adults ≥60 years of age ( 5 ). However, most available data on the burden of RSV-associated disease are focused on children 100 mm for swelling and erythema, an axillary temperature >39°C for fever, and as preventing normal everyday activities for the other events. The grading of solicited events was also done according to the guiding principles for grading criteria for adverse reactions in clinical trials of prophylactic vaccines formulated by the National Medical Products Administration (NMPA) in China (version 2019) ( 16 ). According to the Chinese grading scale, Grade 3 erythema or swelling was defined as a diameter ≥100 mm and Grade 3 fever, as an axillary temperature ≥38.5°C; additionally, Grade 4 fever (≥39.5°C lasting more than 3 days) was reported. Unsolicited adverse events (AEs) were recorded by the investigator for 30 days post-vaccination for participants in China and graded by intensity. Serious AEs (SAEs), potential immune-mediated diseases (pIMDs), SAEs of atrial fibrillation, and (S)AEs leading to withdrawal were reported throughout the study in all groups. Investigators used their clinical judgment to decide whether AEs were related to study interventions. Surveillance for detection of ARI episodes was carried out throughout the study in China, via spontaneous reporting by the participant (starting on Day 1) and by scheduled site staff contacts (starting from Day 31 onwards) with different frequencies of contact during the RSV season and the interseason periods. All participants reporting ≥2 ARI symptoms/signs meeting the ARI case definition (presence of ≥2 respiratory symptoms/signs for at least 24 hours or ≥1 respiratory symptom/sign and 1 systemic symptom/sign for at least 24 hours, as described in Supplementary Table 1 ) were followed-up for ARI assessment. Nasal self-swab or nasal and throat swab samples (by study staff) were collected and tested for RSV by reverse transcription PCR (RT-PCR). Case definitions for RSV-ARI/LRTD are detailed in Supplementary Table 1 . Each ARI episode was diagnosed and managed according to local standard of care. 2.4 Statistical methods The study was designed to enroll approximately 2600 participants, including 1800 participants in China, and 800 participants in the RSVPreF3_Overseas group. A sensitivity analysis was performed under multiple plausible immunogenicity scenarios, assuming a 10% attrition rate. The analysis demonstrated that the sample size would yield ≥90% power for evaluating the co-primary non-inferiority objectives. Power was estimated using a 2-sample t-test for GMT comparisons, and the Miettinen and Nurminen ( 17 ) method for SRRs. Immunogenicity was assessed in the per protocol set that included all eligible participants who received the study intervention as per protocol, had immunogenicity results pre- and post-vaccination, complied with blood draw intervals, had no intercurrent conditions that could interfere with immunogenicity, and no prohibited concomitant medication/vaccination. For the co-primary immunogenicity endpoints, GMT ratios with 2-sided 95% CIs were calculated with an ANCOVA model on log 10 -transformed titers for each neutralization titer; the model included the group as fixed effect and the baseline log 10 -transformed titer as covariate. The 2-sided 95% CIs for group SRR difference were derived using the Miettinen-Nurminen method ( 17 ). Primary analysis results were reported as ED60. Within-group mean geometric increases (MGIs), defined as the geometric mean of the within-participant ratios of the post-vaccination over pre-vaccination titer, were also estimated. 95% CIs for GMTs and MGIs were based on a back-transformation of CIs for the mean of log 10 -transformed values. When computing GMTs, SRRs, MGIs, and between-group differences, titers below the assay cut-off (lower limit of quantification [LLOQ]) were replaced by half the assay cut-off (LLOQ/2) and titers above the upper limit of quantification (ULOQ) were replaced by the ULOQ. All analyses of between-group secondary immunogenicity endpoints were descriptive, with no adjustment for multiplicity. Safety analyses were conducted in the exposed set, which included all participants receiving study intervention. The percentage of participants reporting AEs was calculated with exact 95% CIs using the Clopper-Pearson method ( 18 ). For ARI surveillance, the number and percentage (with exact 95% CIs) of participants who reported at least 1 RSV-confirmed ARI/adjudicated LRTD episodes were computed. Analyses were performed using SAS Viya version 4.0. Missing data were not imputed. 3 Results 3.1 Study participants Overall, 2620 participants were enrolled and received the study intervention: 1199 in the RSVPreF3_China group, 601 in the Placebo_China group, and 820 in the RSVPreF3_Overseas group; 1191, 598, and 816 participants, respectively, were included in the per protocol set at Day 1 ( Figure 3 ). In total, 2577 participants completed the study: 1176 in the RSVPreF3_China group, 589 in the Placebo_China group, and 812 in the RSVPreF3_Overseas group, with the most common reason for not completing being withdrawal by the participant ( Figure 3 ). Figure 3 Study participant flowchart. AE, adverse event; N, number of participants in each group; PPS, per protocol set. In the per protocol set at Day 1, the mean age at vaccination was 70.1 years (varying from 69.8 to 70.5 across the 3 groups) and most participants (50.6% overall, 48.5%–52.3% across groups) were in the 60–69 years of age category. Slightly more than half of participants (52.0% overall, 50.3%–53.6% across groups) were female. Characteristics were balanced between the RSVPreF3_China and Placebo_China groups. Some differences were observed between Chinese and overseas participants for body mass index (≤25.1 versus 27.6 kg/m 2 ), frailty status (≥49.8% versus 26.1% pre-frail and ≤49.3% versus 73.7% fit participants), and smoking status for tobacco (≥17.6% versus 10.8% current smokers) ( Table 1 ). Baseline characteristics for the exposed set are detailed in Supplementary Table 2 . Table 1 Characteristic RSVPreF3_China N=1191 Placebo_China N=598 RSVPreF3_Overseas N=816 Total N=2605 Mean age ± SD, years 69.8 ± 6.6 69.9 ± 6.7 70.5 ± 6.8 70.1 ± 6.7 Age category, n (%) 60–69 years 608 (51.0) 313 (52.3) 396 (48.5) 1317 (50.6) 70–79 years 476 (40.0) 221 (37.0) 322 (39.5) 1019 (39.1) ≥80 years 107 (9.0) 64 (10.7) 98 (12.0) 269 (10.3) Female, n (%) 616 (51.7) 301 (50.3) 437 (53.6) 1354 (52.0) Race, n (%) Asian - Central/South Asian Heritage 0 (0.0) 0 (0.0) 9 (1.1) 9 (0.3) Asian - Chinese Heritage 1191 (100) 598 (100) 2 (0.2) 1791 (68.8) Asian - Korean Heritage 0 (0.0) 0 (0.0) 60 (7.4) 60 (2.3) Asian - Japanese Heritage 0 (0.0) 0 (0.0) 30 (3.7) 30 (1.2) White-Caucasian/European Heritage 0 (0.0) 0 (0.0) 704 (86.3) 704 (27.0) Other 0 (0.0) 0 (0.0) 11 (1.4) 11 (0.4) Mean BMI (± SD), kg/m² 25.0 ± 3.3 25.1 ± 3.1 27.6 ± 4.8 25.9 ± 3.9 Frailty status, n (%) Frail 13 (1.1) 5 (0.8) 2 (0.2) 20 (0.8) Pre-frail 607 (51.0) 298 (49.8) 213 (26.1) 1118 (42.9) Fit 571 (47.9) 295 (49.3) 601 (73.7) 1467 (56.3) Smoker status for tobacco Current smoker 210 (17.6) 110 (18.4) 88 (10.8) 408 (15.7) Former smoker 167 (14.0) 80 (13.4) 316 (38.7) 563 (21.6) Never smoked 814 (68.3) 408 (68.2) 41
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