Abstract
Background
Respiratory syncytial virus (RSV) poses substantial health risks to elderly adults and adults with certain underlying conditions. In a multi-country phase 3 trial (AReSVi-006), the adjuvanted RSVPreF3 vaccine has shown high efficacy against RSV disease. This post-hoc sub-analysis assessed immunogenicity, immunopersistence up to 24 months, and safety of a single dose of the adjuvanted RSVPreF3 vaccine in the Korean cohort.
Materials and Methods
In the global, randomized, observer-blind, placebo-controlled phase 3 trial (NCT04886596), adults ≥60 years of age were randomized 1:1 to receive a single intramuscular dose of the adjuvanted RSVPreF3 vaccine or placebo. The Korean cohort (12 sites) included 719 participants. Immunogenicity and reactogenicity were evaluated in a subset of participants. Safety data included solicited adverse events (AEs) within four days, unsolicited AEs up to 30 days, and serious adverse events (SAEs)/potential immune-mediated diseases up to six months post-vaccination.
Results
In the Korean cohort, 360 participants received the adjuvanted RSVPreF3 vaccine and 359 received placebo; 91 were included in the solicited safety set and 87 in the per-protocol immunogenicity set. By Day 31, neutralizing titers had increased robustly in the RSVPreF3 group with a mean geometric increase (MGI) versus baseline of 7.7 (RSV-A) and 7.2 (RSV-B); RSVPreF3-binding IgG concentrations showed an MGI of 13.4 in the RSVPreF3 group. Reactogenicity was mostly mild; solicited administration-site AEs occurred in 58.7% (predominantly pain) and solicited systemic AEs in 60.9% (predominantly fatigue) of participants in the RSVPreF3 group; no vaccine-related SAEs were reported. RSV-A and RSV-B neutralizing titers and RSVPreF3-binding IgG concentrations remained above baseline until 24 months post-vaccination, with an MGI of 2.2 (RSV-A), 1.3 (RSV-B), and 2.7 (RSVPreF3-binding IgG).
Conclusion
In Korean adults aged ≥60 years, a single dose of the adjuvanted RSVPreF3 vaccine elicited a robust immune response, which persisted for up to 24 months post-vaccination, with an acceptable safety profile.
Trial Registration
ClinicalTrials.gov Identifier: NCT04886596
Keywords: Respiratory syncytial virus, Human, Respiratory syncytial virus vaccine, Safety, Vaccine preventable diseases
Graphical Abstract
Introduction
Respiratory syncytial virus (RSV)-associated acute respiratory illnesses may pose a considerable health threat, especially in children, older adults and adults with certain underlying conditions [1]. In high-income countries, an estimated 470,000 hospitalizations and 33,000 in-hospital deaths of adults ≥60 years of age could be attributed to RSV infection in 2019 [2]. Also in Korea, RSV infections are associated with a substantial burden. A recent review, focused on the Asia Pacific region, showed that among Korean adults over 18 years of age with an acute respiratory infection (ARI) or pneumonia, 1.2% to 7.5% had an RSV infection. A median proportion of 28.6% of these RSV-infected adults were aged 60 years or older. Patients who were hospitalized, spent an average of 20.4 days in the hospital and 26.7% needed intensive care [3]. In another narrative review focused on Korea, RSV was reported in 2.8% of adults presenting with influenza-like illness at emergency departments, and in up to 25% of adults with asthma [4]. Among hospitalized adults with RSV infection in Korea, 64.7% were older than 65 years of age and the overall in-hospital mortality rate was 7.9% [5]. Another study showed intensive care unit admission rates of 25.0% and in-hospital mortality of 10.6% in older adults hospitalized with RSV infection [6]. Similar to global observations in temperate regions, RSV infections in Korea follow a seasonal pattern, with most infections occurring during the winter months (between November and January) [7].
Natural infection with RSV typically induces a short-lived and incomplete immunity, allowing for recurrent infections throughout life [8,9]. The immune response typically involves both a humoral component, through production of neutralizing antibodies, and a cellular component to prevent RSV from infecting host cells, and limit the severity of RSV disease through triggering of inflammation around infected cells and providing viral clearance [10]. After an acute infection, anti-RSV antibody titers decline, and the natural protection wanes within one to two years [11]. In older adults, immunosenescence further reduces the protective responses to RSV infection and may lead to increased inflammation and more severe RSV disease [10]. Understanding how robust and long-lasting vaccine-induced immunity can be maintained is thus of clinical relevance and has important public health implications. Since RSV is a recurrent, seasonal threat in older adults, vaccine-induced protection that quickly wanes would necessitate annual re-vaccinations, with a corresponding burden on the healthcare system. Conversely, long-term immunity could lead to extended vaccination schedules, improving the cost-effectiveness and feasibility, particularly in rapidly aging societies, such as in Korea.
The AS01E-adjuvanted RSVPreF3 vaccine, based on the RSV fusion (F) protein stabilized in its prefusion conformation (Arexvy, GlaxoSmithKline Biologicals SA, Rixensart, Belgium) was the first vaccine to be approved in the United States [12] and in Europe [13] for the prevention of lower respiratory tract disease (LRTD) in adults over 60 years of age, and in adults over 50 years of age who are at increased risk for RSV disease. In Korea, the adjuvanted RSVPreF3 vaccine was approved by the Ministry of Food and Drug Safety in 2024 [14].
In the global AReSVi-006 pivotal phase 3 trial, over 25,000 participants aged ≥60 years were enrolled between May 2021 and January 2022 [15]. Vaccine efficacy against RSV-LRTD was confirmed over two seasons (67.2% after single dose, 67.1% after two annual doses) [16]. Results over three RSV seasons further confirmed the efficacy of a single adjuvanted RSVPreF3 dose in preventing RSV-LRTD with a clinically acceptable safety profile (cumulative efficacy: 62.9%) [17]. We have performed a sub-analysis of the AReSVi-006 data to investigate the immune response and persistence over 24 months following vaccination and safety of a single dose of the adjuvanted RSVPreF3 vaccine in the Korean population.
Materials and Methods
1. Study design and participants
The AReSVi-006 study (NCT04886596) was a worldwide, randomized, observer-blind, placebo-controlled phase 3 trial, conducted in 275 centers in 17 countries (12 centers in Korea). Detailed methods were published previously [15,16,17].
Participants in the AReSVi-006 study were adults aged ≥60 years who were considered medically stable by the investigator, including individuals with chronic, medically stable comorbidities (study enrollment: May 25, 2021 to Jan 31, 2022). Results for the first three consecutive RSV seasons in the Northern Hemisphere (‘season’ was defined as October 1 to April 30 of the following calendar year) and at least two consecutive RSV seasons in the Southern Hemisphere (‘season’: March 1 to September 30) have been published previously [17].
2. Ethics statement
This study was conducted in accordance with the Protocol and consensus ethical principles derived from international guidelines including the Declaration of Helsinki, CIOMS International Ethical Guidelines, applicable ICH GCP Guidelines, and other applicable laws and regulations. The study was registered on ClinicalTrials.gov (NCT04886596), all relevant study documents were approved by the relevant institutional review boards/institutional ethics committees prior to site initiation, and subsequent amendments were approved prior to implementation. All participants provided written informed consent, prior to enrollment into the study.
3. Objectives
The objectives of this post-hoc, country-specific sub-analysis were to evaluate the immunogenicity and safety of a single dose of the adjuvanted RSVPreF3 vaccine and the immunopersistence up to 24 months after vaccination, in terms of RSV-A/B neutralizing titers and RSVPreF3-binding IgG concentrations, in the Korean cohort of the AReSVi-006 trial.
4. Procedures
All participants were randomized (1:1) to receive one intramuscular injection of the adjuvanted RSVPreF3 vaccine or placebo (Fig. 1). An internet-based automated system was used in the global AReSVi-006 trial (including the Korean cohort) with a minimization procedure accounting for center, age and region (Northern or Southern Hemisphere). All minimization factors had equal weight.
Figure 1. Study design.
Note: Immunogenicity and reactogenicity were assessed in a subset of the study participants.
AE, adverse event; pIMD, potential immune-mediated disease; SAE, serious adverse event.
In the AReSVi-006 trial, the immunogenicity and reactogenicity were assessed in a subset of the participants, comprising approximately 7% of the total, global study population. In a selected number of sites, the first participants enrolled in each age category were assigned to this subset, until the allocated target number of participants was reached. In this subset, serum samples were collected pre-vaccination, 30 days post-vaccination, pre-season 2 (i.e., 12 months after vaccination), and pre-season 3 (i.e., 2 months after vaccination), and analyzed for RSV-A and RSV-B neutralizing titers and RSVPreF3-binding IgG concentrations as described previously [15].
Reactogenicity was assessed in the subset by collecting solicited administration-site and systemic adverse events (AEs) starting within four days after the injection. Safety was assessed by collecting data on unsolicited AEs starting within 30 days after the injection, as well as serious adverse events (SAEs) and potential immune-mediated diseases (pIMDs) starting within six months after the injection in all study participants. All AEs were followed up until resolution; SAEs and pIMDs that were considered related to the study intervention, fatal SAEs, and AEs or SAEs that led to participant withdrawal were monitored until study end.
5. Statistical methods
Detailed statistical methods were published previously [17]. All analyses specifically performed for the current sub-analysis were performed descriptively.
Immunogenicity was assessed in terms of geometric mean titers of RSV neutralizing antibodies and geometric mean concentration of RSVPreF3-binding IgG, as well as mean geometric increase (MGI, geometric mean of the within-participant ratio of post- versus pre-vaccination titers or concentrations) in the participants who did not have protocol deviations and had immunogenicity data available, i.e., the per-protocol population for immunogenicity. Reactogenicity was assessed in the subset of participants who had solicited AE data available, i.e., the solicited safety population. Safety outcomes were analyzed descriptively, using data from all participants who received study vaccine or placebo, i.e., the exposed set. Within-group proportions were calculated with exact 95% confidence intervals (CIs).
Results
1. Study participants
In the 12 participating Korean clinical centers, a total of 719 participants were enrolled in the study (360 participants in the RSVPreF3 group and 359 in the placebo group) and received the study intervention (exposed set). Of these, 87 (12.1%) were included in the per-protocol set for immunogenicity (43 in the RSVPreF3 group and 44 in the placebo group), and 91 (12.7%) were included in the solicited safety set (46 in the RSVPreF3 group and 45 in the placebo group) (Fig. 2).
Figure 2. Participant disposition.
RSVPreF3, participants who received the adjuvanted RSVPreF3 vaccine; Placebo, participants who received placebo.
AE, adverse event; N, number of participants in the South Korean population; RSV, respiratory syncytial virus; RSVPreF3, adjuvanted RSV prefusion F vaccine.
Overall, demographic characteristics of the Korean participants were well balanced between study groups. All participants in the Korean population were of Asian race. All participants but one were community-dwelling. The overall mean age was 68.2 (±5.8) years, 66.5% were female, and most participants were classified as ‘pre-frail’ (58.7%) or ‘fit’ (34.1%) using the gait speed test [17]; 86.1% were at low to medium comorbidity risk according to the Charlson Comorbidity Index and 22.5% had at least one pre-existing comorbidity of interest (5.6% cardiorespiratory, 18.5% endocrinometabolic) (Table 1).
Table 1. Demographic and baseline characteristics of the Korean population (exposed set).
| Characteristic | RSVPreF3 N=360 | Placebo N=359 | Overall N=719 | ||
|---|---|---|---|---|---|
| Age (years)a | 67.9±5.5 | 68.6±6.1 | 68.2±5.8 | ||
| Age categorya | |||||
| ≥65 years | 244 (67.8) | 250 (69.6) | 494 (68.7) | ||
| ≥70 years | 127 (35.3) | 132 (36.8) | 259 (36.0) | ||
| 60–69 years | 233 (64.7) | 227 (63.2) | 460 (64.0) | ||
| 70–79 years | 116 (32.2) | 112 (31.2) | 228 (31.7) | ||
| ≥80 years | 11 (3.1) | 20 (5.6) | 31 (4.3) | ||
| Sex | |||||
| Female | 249 (69.2) | 229 (63.8) | 478 (66.5) | ||
| Male | 111 (30.8) | 130 (36.2) | 241 (33.5) | ||
| BMI (kg/m2) | 24.8±2.8 | 25.0±3.3 | 24.9±3.0 | ||
| Frailty statusb | |||||
| Frail | 26 (7.2) | 26 (7.2) | 52 (7.2) | ||
| Pre-frail | 213 (59.2) | 209 (58.2) | 422 (58.7) | ||
| Fit | 121 (33.6) | 124 (34.5) | 245 (34.1) | ||
| Smoking status | |||||
| Current smoker | 30 (8.3) | 31 (8.6) | 61 (8.5) | ||
| Former smoker | 50 (13.9) | 67 (18.7) | 117 (16.3) | ||
| Never smoker | 280 (77.8) | 261 (72.7) | 541 (75.2) | ||
| Charlson Comorbidity Index categoryc | |||||
| Low/medium risk | 311 (86.4) | 308 (85.8) | 619 (86.1) | ||
| High risk | 49 (13.6) | 51 (14.2) | 100 (13.9) | ||
| Comorbidity of interestd | |||||
| At least 1 pre-existing comorbidity of interest | 83 (23.1) | 79 (22.0) | 162 (22.5) | ||
| Cardiorespiratory condition | 27 (7.5) | 13 (3.6) | 40 (5.6) | ||
| Endocrinometabolic condition | 63 (17.5) | 70 (19.5) | 133 (18.5) | ||
Value ± standard deviation, or number (%) of participants in each category.
RSVPreF3, participants who received the adjuvanted RSVPreF3 vaccine; Placebo, participants who received placebo.
aAt vaccine/placebo administration.
bBased on the gait speed test. Frail, participants with walking speed <0.4 m/s or who were unable to perform the test; Pre-frail, participants with walking speed between 0.4 and 0.99 m/s; Fit, participants with walking speed ≥1 m/s.
cCharlson Comorbidity score at baseline: ≤3, Low/medium risk; >3, High risk.
dComorbidities of interest were chronic obstructive pulmonary disease, asthma, any chronic respiratory or pulmonary disease, diabetes mellitus type 1 or type 2, chronic heart failure, and advanced liver or renal disease.
BMI, body mass index; N, number of participants.
2. Immunogenicity
In the subset for immunogenicity, participants who received the adjuvanted RSVPreF3 vaccine showed a robust increase in RSV neutralizing titers 30 days post-vaccination versus baseline, with an MGI of 7.7 (95% CI, 5.8–10.2; N=43) for RSV-A and 7.2 (5.5–9.4; N=43) for RSV-B. In the placebo group, no increase was observed for RSV-A (MGI, 1.1 [0.8–1.5]; N=44) or for RSV-B (MGI, 1.0 [0.9–1.2]; N=44) (Fig. 3 , panels A and B). RSVPreF3-binding IgG concentrations increased 30 days post-vaccination, with an MGI of 13.4 (10.8–16.8; N=43) in the participants who received the adjuvanted RSVPreF3 vaccine, versus 1.0 (0.9–1.0; N=44) in the participants who received placebo (Fig. 3, panel C).
Figure 3. Geometric mean RSV-A and RSV-B neutralizing titers (A and B), and RSVPreF3 binding IgG antibody concentrations (C) at baseline and 30 days post-dose (left panels) and immunopersistence up to 24 months post-vaccination (right panels).
RSV, respiratory syncytial virus; Ab, antibody; CI, confidence interval; D, day; ED60, estimated dilution 60; EU, ELISA units; GMT, geometric mean titer; IgG, immunoglobulin G; MGI, mean geometric increase.
At 24 months post-vaccination, the MGI (versus baseline) for RSV-A neutralizing titers decreased from 6.9 (95% CI, 4.4–10.9; N=19) at 30 days post-vaccination to 2.2 (1.4–3.4; N=18) in the RSVPreF3 group; for RSV-B neutralizing titers, the MGI decreased from 6.1 (4.0–9.3; N=19) at 30 days post-vaccination to 1.3 (1.0–1.9; N=18) at 24 months post-vaccination. Both RSV-A and RSV-B neutralizing titers remained above baseline up to 24 months post-vaccination (Fig. 3).
A similar evolution was seen for RSVPreF3-binding IgG concentrations, with an MGI decrease from 10.9 (8.2–14.6; N=19) to 2.7 (2.1–3.4; N=18). RSVPreF3-binding IgG concentrations remained above baseline for up to 24 months post-vaccination (Fig. 3).
3. Reactogenicity and safety
Solicited AE data were available for ≥98.8% of participants in the subset for reactogenicity. Within four days post-vaccination, none of the participants in the placebo group reported a solicited administration-site event. In the RSVPreF3 group, 58.7% of participants reported a solicited administration-site event, with a median duration of three days. Pain was the most commonly reported solicited administration-site event (56.5% in the RSVPreF3 group) (Table 2). Grade 3 solicited administration-site events were reported by 4.3% of participants in the RSVPreF3 group.
Table 2. Number of participants reporting solicited administration-site and solicited systemic adverse events within 4 days post-vaccination (solicited safety population).
| Event | RSVPreF3, N=46 | Placebo, N=45 | |||
|---|---|---|---|---|---|
| n | % (95% CI) | n | % (95% CI) | ||
| Any administration-site AE | 27 | 58.7 (43.2–73.0) | 0 | 0 (0.0–7.9) | |
| Grade 3 | 2 | 4.3 (0.5–14.8) | 0 | 0 (0.0–7.9) | |
| Pain | 26 | 56.5 (41.1–71.1) | 0 | 0 (0.0–8.0) | |
| Grade 3 | 1 | 2.2 (0.1–11.5) | 0 | 0 (0.0–8.0) | |
| Erythema | 5 | 10.9 (3.6–23.6) | 0 | 0 (0.0–8.0) | |
| Grade 3 | 0 | 0 (0.0–7.7) | 0 | 0 (0.0–8.0) | |
| Swelling | 3 | 6.5 (1.4–17.9) | 0 | 0 (0.0–8.0) | |
| Grade 3 | 1 | 2.2 (0.1–11.5) | 0 | 0 (0.0–8.0) | |
| Any systemic AE | 28 | 60.9 (45.4–74.9) | 8 | 17.8 (8.0–32.1) | |
| Grade 3 | 3 | 6.5 (1.4–17.9) | 0 | 0 (0.0–7.9) | |
| Fevera | 0 | 0 (0.0–7.7) | 0 | 0 (0.0–7.9) | |
| Grade 3 | 0 | 0 (0.0–7.7) | 0 | 0 (0.0–7.9) | |
| Headache | 16 | 34.8 (21.4–50.2) | 6 | 13.3 (5.1–26.8) | |
| Grade 3 | 0 | 0 (0.0–7.7) | 0 | 0 (0.0–7.9) | |
| Fatigue | 22 | 47.8 (32.9–63.1) | 5 | 11.1 (3.7–24.1) | |
| Grade 3 | 1 | 2.2 (0.1–11.5) | 0 | 0 (0.0–7.9) | |
| Myalgia | 20 | 43.5 (28.9–58.9) | 3 | 6.7 (1.4–18.3) | |
| Grade 3 | 2 | 4.3 (0.5–14.8) | 0 | 0 (0.0–7.9) | |
| Arthralgia | 12 | 26.1 (14.3–41.1) | 1 | 2.2 (0.1–11.8) | |
| Grade 3 | 2 | 4.3 (0.5–14.8) | 0 | 0 (0.0–7.9) | |
aFever defined as temperature ≥38.0°C.
Grade 3 was defined as diameter >100 mm for swelling and erythema, fever >39.0°C, and preventing normal everyday activities for all other AEs.
RSVPreF3, participants who received the adjuvanted RSVPreF3 vaccine; Placebo, participants who received placebo; N, number of participants in each group; n, number of participants reporting a solicited AE.
AE, adverse event; CI, confidence interval; RSV, respiratory syncytial virus.
Solicited systemic AEs occurring within four days post-vaccination were reported by 60.9% of the participants in the RSVPreF3 group and 17.8% of the participants in the placebo group, with a median duration across both groups of three days or less. The most commonly reported solicited systemic AE across groups was fatigue (reported by 47.8% of participants in the RSVPreF3 group and 11.1% in the placebo group) (Table 2). Grade 3 solicited systemic AEs were reported by three participants (6.5%) in the RSVPreF3 group.
No vaccine-related or fatal SAEs were reported. In the placebo group, two pIMDs were reported: gastric cancer (within 6 months after the second dose) and myopericarditis (within 6 months after the first dose); both were considered not related to the study intervention by the investigator (Table 3).
Table 3. Number of participants reporting unsolicited adverse events within 30 days post-vaccination, and serious adverse events and potential immune-mediated diseases up to six months post-vaccination (exposed set).
| Event | RSVPreF3 N=360 | Placebo N=359 | |||
|---|---|---|---|---|---|
| n | % (95% CI) | n | % (95% CI) | ||
| Any unsolicited AE | 157 | 43.6 (38.4–48.9) | 46 | 12.8 (9.5–16.7) | |
| Grade 3 | 3 | 0.8 (0.2–2.4) | 2 | 0.6 (0.1–2.0) | |
| Any related, unsolicited AE | 149 | 41.4 (36.3–46.7) | 22 | 6.1 (3.9–9.1) | |
| Grade 3 | 2 | 0.6 (0.1–2.0) | 1 | 0.3 (0.0–1.5) | |
| Any medically attended, unsolicited AE | 25 | 6.9 (4.5–10.1) | 15 | 4.2 (2.4–6.8) | |
| Any SAE | 8 | 2.2 (1.0–4.3) | 8 | 2.2 (1.0–4.3) | |
| Any pIMD | 0 | 0 (0.0–1.0) | 1 | 0.3 (0.0–1.5) | |
RSVPreF3, participants who received the adjuvanted RSVPreF3 vaccine; Placebo, participants who received placebo.
AE, adverse event; CI, confidence interval; N, number of participants in each group; n, number of participants reporting an unsolicited AE; pIMD, potential immune-mediated disease; RSV, respiratory syncytial virus; SAE, serious adverse event.
Discussion
In older adults or adults with underlying medical condition, RSV continues to cause clinically meaningful disease, with recurrent seasonal surges that place a sustained burden on health systems. Although infection can occur frequently throughout life, the immune response induced by natural exposure is transient and does not confer durable protection, underscoring the need for preventive strategies capable of generating longer-lasting immunity. The adjuvanted RSVPreF3 vaccine was developed within this context and has demonstrated maintained efficacy across consecutive RSV seasons in the pivotal phase 3 trial [15,16,17]. Here, we present the first Korean-specific data on the immunogenicity, immunopersistence and safety of the adjuvanted RSVPreF3 vaccine in adults ≥60 years of age. The Korean cohort of the AReSVi-006 trial represented a typical community-dwelling population of older adults in Korea with similar age, frailty and risk for pre-existing comorbidities.
The immunogenicity profile of the adjuvanted RSVPreF3 vaccine in the Korean participants is consistent with the overall global trends and suggests a strong immune response [15,16,17]. Thirty days after a single dose of the adjuvanted RSVPreF3 dose vaccine, RSV-A and RSV-B neutralizing titers increased approximately 7.5-fold, while RSVPreF3-binding IgG concentrations increased approximately 13-fold. Although the immune response to the adjuvanted RSVPreF3 vaccine declined over time, a 1.3 to 2.7-fold increase in neutralizing titers and antibody concentrations versus baseline was shown up to 24 months after vaccination. These findings are consistent with the global cohort, which showed an approximate 8 to 10-fold increase in RSV-A and RSV-B neutralizing titers, and a 13-fold increase in RSVPreF3-binding IgG concentrations 30 days after a single dose, which waned to a 1.7- to 3.0-fold increase at 24 months after vaccination [17].
As described previously, natural infection induces a limited and short-lived immune response [8,9,11]. In contrast, vaccination with the adjuvanted RSVPreF3 vaccine induces a robust response, which persists and stays above baseline for up to at least 24 months. The high baseline titers observed prior to the administration of adjuvanted RSVPreF3 vaccine or placebo suggest that the participants had been previously exposed to naturally circulating RSV. Additionally, the relative stable titers in the placebo group over the follow-up period may reflect cumulative exposure to RSV.
The reactogenicity and safety results in the Korean population were similar to the global results [15,16,17] and showed that the adjuvanted RSVPreF3 vaccine is generally well tolerated with an acceptable safety profile. Reactogenicity was generally transient and predominantly mild to moderate, with administration-site pain and fatigue being the most commonly reported events. The proportion of grade 3 solicited events was low and comparable to global rates. No vaccine-related serious adverse events were identified, and the incidence of pIMDs was minimal and judged unrelated to vaccination.
This sub-analysis has several limitations. First, the immunogenicity and reactogenicity subsets were relatively small, which limits precision and statistical power for subgroup comparisons. Second, immunogenicity was assessed using humoral endpoints only; cellular immune responses, which may be particularly relevant in older adults, were not measured in this study. However, a previous phase 3 study which evaluated immunogenicity and safety of the adjuvanted RSVPreF3 vaccine, a one-dose vaccination elicited cell-mediated immune response for at least one year [18]. Third, although the cohort reflects community-dwelling older Koreans, institutionalized or more frail populations were underrepresented, potentially limiting generalizability. Finally, as a post-hoc sub-analysis, these findings should be considered exploratory and hypothesis-generating.
Nevertheless, this sub-analysis provides the first long-term immunogenicity and safety data in a well-characterized Korean population from a large, multi-country phase 3 trial. The Korean cohort reflects a typical community-dwelling older adult population with representative distributions of frailty and comorbidities, strengthening our findings as well as supporting the generalizability of these findings to real-world settings. We demonstrate a robust and persistent immune response up to at least 24 months post-vaccination, with an acceptable safety profile. Our findings align with the global AReSVi-006 results, which have demonstrated sustained immunogenicity and efficacy over three consecutive RSV seasons. The consistency of Korean results with the overall global dataset supports the applicability of adjuvanted RSVPreF3 vaccination to older adults in Korea. The results from this sub-analysis show that adjuvanted RSVPreF3 vaccination may offer protection extending beyond a single RSV season, thereby informing considerations for optimal vaccination timing in countries like Korea where seasonal RSV activity shows consistent annual peaks. Although further research is needed to establish the optimal re-vaccination strategies and timings, the sustained immune responses up to at least 24 months provide evidence to inform national vaccination policies and may contribute to optimizing long-term RSV prevention strategies in the context of Korea’s rapidly aging population.
In conclusion, we show that the adjuvanted RSVPreF3 vaccine is immunogenic, well tolerated, and the immune response persists up to at least 24 months in older Korean adults. These findings align with the global AReSVi-006 results, which have demonstrated sustained immunogenicity and efficacy over three consecutive RSV seasons.
ACKNOWLEDGEMENTS
The authors would like to thank all study participants, investigators and GSK study staff involved in the study. The authors also thank Akkodis Belgium for medical writing (Geert Behets), design and coordination support on behalf of GSK.
Footnotes
Funding: This work was supported by GSK (Study ID: 212494). GSK was involved in all stages of the study conduct and analysis and took responsibility for all costs associated with the development and the publishing of the present manuscript.
Conflict of Interest: SBP, SM, SKS, SX, GZ, MZ, and MVDW are employed by GSK. SBP, SM, GZ, MZ, and MVDW hold financial equities in GSK. MVDW is listed as an inventor on a vaccine patent filed by GSK. DGL is editorial board of Infect Chemother; however, he was not involved in the peer reviewer selection, evaluation, and decision process of this article. Otherwise, no potential conflicts of interest relevant to this article was reported.
Data sharing statement: GSK makes available anonymized individual participant data and associated documents from interventional clinical studies which evaluate medicines, upon approval of proposals submitted to www.clinicalstudydatarequest.com. To access data for other types of GSK sponsored research, for study documents without patient-level data and for clinical studies not listed, please submit an enquiry via the website.
Previous presentation: The data reported in the current manuscript were presented in part as a Poster at the 26th Autumn Conference of the Korean Vaccine Society, 19 September 2025, in Seoul, Korea.
AReSVi-006 study group members (listed alphabetically): Adams Mark, Adams Michael, Agutu Clara, Akite Elaine Jacqueline, Alt Ingrid, Andrews Charles, Antonelli-Incalzi Rafaelle, Asatryan Asmik, Athan Eugene, Bahrami Ghazaleh, Bargagli Elena, Bhorat Qasim, Bird Paul, Borowy Przemyslaw, Boutry Celine, Brotons Cuixart Carles, Browder David, Brown Judith, Buntinx Erik, Cameron Donald, Cartier Cyrille, Chinsky Kenneth, Choi Melissa, Choo Eun-Ju, Collete Delphine, Corral Carrillo Maria, Cuadripani Susanna, David Marie-Pierre, Davis Matthew G, de Heusch Magali, de Looze Ferdinandus, De Meulemeester Marc, De Negri Ferdinando, DeAtkine David, Dedkova Viktoriya, Deraedt Quentin, Descamps Dominique, Dezutter Nancy, Dzongowski Peter, Eckermann Tamara, Essink Brandon, Faulkner Karen, Feldman Robert, Ferguson Murdo, Fissette Laurence, Fuller Gregory, Galan Melendez Isabel Maria, Gentile Ivan, Gerard Catherine, Ghesquiere Wayne, Grimard Doria, Gruselle Olivier, Halperin Scott, Halpin David MG, Heer Amardeep, Helman Laura, Hotermans Andre, Hulstrom Veronica, Ison Michael G, Jelinek Tomas, Kamerbeek Jackie, Kim Hyo Youl, Kimmel Murray, Koch Mark, Kokko Satu, Koski Susanna, Kotb Shady, Lalueza Antonio, Langley Joanne M, Lee Jin-Soo, Leroux-Roels Isabel, Lins Muriel, Lombaard Johannes, Mahomed Akbar, Malerba Mario, Marechal Celine, Martinon-Torres Federico, Marion Sandie, Martinot Jean-Benoit, Masuet-Aumatell Cristina, McNally Damien, Medina Pech Carlos Eduardo, Mendez Galvan Jorge, Mercati Lise, Mesotten Dieter, Michaud Jean-Philippe, Mitha Essack, Mngadi Kathryn, Moeckesch Beate, Montgomery Barnaby, Murray Linda, Nally Rhiannon, Narejos Perez Silvia, Newberg Joseph, Nugent Paul, Ochoa Mazarro Dolores, Oda Harunori, Olivier Aurelie, Orso Maurizio, Ortiz Molina Jacinto, Pak Tatiana, Park Dae Won, Papi Alberto, Patel Meenakshi, Patel Minesh, Pedro Pijoan Anna Maria, Perez Vera Merce, Perez Alberto Borobia, Perez-Breva Lina, Pileggi Claudia, Pregliasco Fabrizio, Pretswell Carol, Quinn Dean, Reynolds Michele, Romanenko Viktor, Rosen Jeffrey, Roy Nathalie, Ruiz Antoran Belen, Sakata Hideaki, Sauter Joachim, Schaefer Axel, Schwarz Tino F, Sein Anand Izabela, Serra Rexach Jose Antonio, Shu David, Siig Andres, Simon William, Smakotina Svetlana, Steenackers Katie, Stephan Brigitte, Tafuri Silvio, Takazawa Kenji, Tellier Guy, Terryn Wim, Tharenos Leslie, Thomas Nick, Toursarkissian Nicole, Ukkonen Benita, Vale Noah, Van Landegem Pieter-Jan, van Zyl-Smit Richard N, Vanden Abeele Carline, Verheust Celine, Vermeersch Lode, Vitale Francesco, Voloshyna Olga, White Judith, Wie Seong-Heon, Wilson Jonathan, Ylisastigui Pedro
Trademark statement: AS01E and Arexvy are trademarks owned by or licensed to the GSK group of companies.
- Conceptualization: MVDW.
- Data curation: MZ, MVDW, DGL.
- Formal analysis: MZ, MVDW, SX, GZ.
- Methodology: SBP, SM, SKS, SX, GZ, MZ, MVDW, DGL.
- Supervision: DGL.
- Validation: SBP, SM, SKS, SX, GZ, MZ, MVDW, DGL.
- Writing - original draft: SBP, SM, SKS, SX, GZ, MZ, MVDW, DGL.
- Writing - review & editing: SBP, SM, SKS, SX, GZ, MZ, MVDW, DGL.
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