Expert Consensus Statement on the Disease Burden and Vaccination for Respiratory Syncytial Virus Infection in Adults

Joon Young Choi; Chin Kook Rhee; Yong-Il Hwang; Ji-Yong Moon; Kwang Ha Yoo; Hyoung Kyu Yoon

doi:10.4046/trd.2025.0173

Tuberc Respir Dis > Volume 89(1); 2026 > Article

Choi, Rhee, Hwang, Moon, Yoo, and Yoon: Expert Consensus Statement on the Disease Burden and Vaccination for Respiratory Syncytial Virus Infection in Adults

Review

Pulmonary Infection

Tuberculosis and Respiratory Diseases 2026;89(1):18-28.

Published online: November 19, 2025

DOI: https://doi.org/10.4046/trd.2025.0173

Expert Consensus Statement on the Disease Burden and Vaccination for Respiratory Syncytial Virus Infection in Adults

Joon Young Choi¹

, Chin Kook Rhee², Yong-Il Hwang³, Ji-Yong Moon⁴, Kwang Ha Yoo⁴, Hyoung Kyu Yoon⁵

¹Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Incheon St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea

²Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea

³Department of Internal Medicine, Hallym University Sacred Heart Hospital, College of Medicine, Hallym University, Anyang, Republic of Korea

⁴Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Republic of Korea

⁵Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Yeouido St Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea

Address for correspondence Hyoung Kyu Yoon Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Yeouido St Mary’s Hospital, College of Medicine, The Catholic University of Korea, 10 63-ro, Yeongdeungpo-gu, Seoul 07345, Republic of Korea Phone 82-2-3779-2213 Fax 82-2-780-3132 E-mail cmcyhg@gmail.com

Received November 5, 2025 Accepted November 9, 2025

It is identical to the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/).

Abstract

Respiratory syncytial virus (RSV) is a leading cause of acute respiratory infection in adults, with higher morbidity and mortality in older adults and those with chronic obstructive pulmonary disease (COPD) or asthma. Despite the burden, disease awareness remains low and treatment is limited to supportive care. Recent advances have led to the approval of multiple vaccines and updated guideline recommendations. We reviewed current literature, surveillance data, and international guidelines to assess the burden of RSV in adults and to evaluate evidence for vaccination in high-risk groups. Globally, RSV accounts for millions of infections and substantial hospitalizations and deaths among adults ≥60 years. COPD and asthma patients show disproportionately high risks of RSV-related hospitalization, exacerbations, and mortality. South Korean studies confirm RSV as a major contributor to pneumonia, COPD and asthma exacerbations, and bronchiectasis. As of 2025, three RSV vaccines (Arexvy, Abrysvo, mRESVIA) have US Food and Drug Administration approval; only Arexvy is approved in Korea for older adults. Advisory Committee on Immunization Practices (ACIP) now recommends vaccination for all adults ≥75 years and high-risk adults aged 50-74 years, while Global Initiative for Chronic Obstructive Lung Disease (GOLD), Global Initiative for Asthma (GINA), and Korean COPD guidelines endorse RSV vaccination for chronic respiratory disease patients. RSV is underrecognized yet imposes significant disease and healthcare burdens in older adults and those with chronic respiratory diseases. In the absence of effective antivirals, vaccination is a key preventive strategy. Expanding vaccination uptake, improving awareness, and integrating RSV vaccines into national immunization programs could substantially reduce RSV-related morbidity and mortality.

Keywords: Respiratory Syncytial Virus; Acute Respiratory Infection; Chronic Obstructive Pulmonary Disease; Asthma; Vaccine

Key Figure

Introduction

Respiratory syncytial virus (RSV) is a single-stranded RNA virus of the family Pneumoviridae, which is one of the most common causes of acute respiratory disease worldwide [1,2], and it is classified into types A and B according to the antigen [1]. RSV is highly contagious, spreads through respiratory secretions, and has an incubation period of 2 to 8 days [1]. Immunity after infection is short-lived, and reinfection can occur frequently throughout life, even within a few weeks after recovery [1].

The clinical spectrum of RSV infection ranges from mild cold-like symptoms to severe lower respiratory tract disease (LRTD), which may lead to hospitalization, intensive care unit (ICU) admission, or death [3]. Recently, as studies investigating the prevalence and mortality of RSV infection among adults at high risk for severe infection, such as the elderly and adults with certain comorbidities, have increased it has been confirmed that RSV infection places a significant burden on the healthcare system [2,3]. The severity of RSV infection is notably higher in people with chronic respiratory diseases, such as chronic obstructive pulmonary disease (COPD) and asthma, and several studies have reported that RSV detected in respiratory samples is a major viral cause of acute asthma and COPD exacerbations [3].

A major limitation in the treatment of RSV infection is the absence of specific antiviral agents [3]. Although ribavirin may be administered in certain immunocompromised patients, its accessibility is limited [3]. For most RSV infections, supportive care, such as intravenous fluids, antipyretics, or oxygen therapy during hospitalization depending on clinical symptoms, remains the only available treatment option [1].

Meanwhile, the development of RSV vaccines began with the stabilization of the pre-fusion (pre-F) protein, which exists prior to viral entry into the host cells [4]. In 2013, a research team led by Barney Graham at the National Institutes of Health first elucidated the stabilized structure of the RSV pre-F protein [4]. Based on this protein, the first RSV vaccine candidate underwent clinical trials, leading to the United States (US) Food and Drug Administration (FDA) approval of RSVPreF3 (Arexvy, GSK, London,UK) in May 2023 [5]. Currently, three vaccines, RSVPreF3 (Arexvy, GSK), RSVpreF (Abrysvo, Pfizer, New York, NY, USA), and mRNA-1345 (mRESVIA, Moderna, Cambridge, MA, USA), have been approved by the FDA for the prevention of LRTDs caused by RSV in adults aged 60 years and older, and as of July 2025 [6], only the RSVPreF3 vaccine has been approved for use in adults aged 60 years and older in South Korea [7]. The Advisory Committee on Immunization Practices (ACIP) of the US Centers for Disease Control and Prevention (CDC) recommends RSV vaccination for adults aged 75 years and older, as well as for high-risk individuals aged 50 to 74 years [8]. Additionally, the Global Initiative for Chronic Obstructive Lung Disease (GOLD) and Global Initiative for Asthma (GINA) guidelines recommend RSV vaccination for patients with COPD and asthma [9,10].

Over the past 20 years, the burden of RSV infection in adults has been increasingly recognized [2]. With the availability of vaccines to prevent RSV infection in adults, it is essential to raise awareness of the importance of prevention among older adults (OA) and individuals with chronic conditions, in the absence of specific treatments [1-3]. This consensus paper aims to understand the burden of RSV infection in adult patients and to review and propose recommendations for preventing RSV-related diseases and complications through vaccination.

The Burden of RSV

1. Global

RSV is one of the most common causes of lower respiratory tract infection (LRTI) in infants and young children and is the second leading cause of LRTI-related mortality worldwide [1,2]. The global incidence of RSV-related LRTIs in children under 5 years of age is estimated to exceed 30 million cases annually, resulting in approximately 3.2 million hospitalizations [2]. In the US, RSV infection is responsible for an estimated 60,000 to 160,000 hospitalizations and 6,000 to 10,000 deaths annually among adults aged 65 years and older [11]. A meta-analysis estimated that, as of 2019, RSV accounted for approximately 5.2 million cases of acute respiratory infection (ARI), 470,000 hospitalizations, and 33,000 in-hospital deaths among adults aged 60 years and older in major high-income countries, including the US, Europe, Canada, Japan, and South Korea [12].

RSV is also recognized as a significant pathogen in OA, immunocompromised individuals, and those with chronic respiratory or cardiac diseases [13]. In a meta-analysis of 31 studies conducted across 17 countries using a random-effects model, COPD was identified as an underlying condition in 27.7% (95% confidence interval [CI], 22.9 to 33.0; heterogeneity I²=89%) of all RSV-infected adults (Table 1) [14-19].

Adults with COPD are known to have an increased risk of RSV-related hospitalization and more severe clinical outcomes, with hospitalization rates for RSV infection being 13 times higher in patients with COPD [14]. One study reported that the incidence rate ratio (IRR) for RSV-related hospitalization in individuals with COPD was 9.6 times (95% CI, 6.2 to 14.8) higher in adults aged 50 to 64 years and 9.7 times (95% CI, 6.3 to 14.9) higher in those aged 65 years and older [14]. In a study that followed 450 patients with COPD over an average of 27 months, the prevalence of RSV was reported as 4.5% at baseline, 2.8% during stable periods, 7.8% during upper respiratory tract infection (URTI), 5.4% at follow-up visits, and 8.6% during acute exacerbation of COPD (AE-COPD) [20]. In another study involving 377 outpatients with COPD, 310 exacerbations were reported over 1 to 3 years, of which 27 (8.3%) were attributed to RSV [21]. Furthermore, among RSV-infected patients with COPD, the overall mortality rate was reported as 10.0% during hospitalization and within 30 days post-discharge, 2.8% within 30 days post-discharge, and 17.8% during hospitalization [14].

In case of asthma, a meta-analysis of 24 studies across 14 countries using a random-effects model found that 17.7% (95% CI, 13.7 to 22.7; heterogeneity I²=93%) of adults aged 18 years and older with RSV infection had underlying asthma (Table 2) [14].

Two studies investigating hospitalization rates by asthma status found that, similar to COPD, adults with asthma had a significantly higher risk of RSV-related hospitalization compared to those without asthma, and the risk generally increased with age [14]. The IRR for hospitalization risk among patients with asthma compared with those without asthma was reported to be 7.6 times higher (95% CI, 4.9 to 11.6) in patients aged 50 to 64 years and 8.2 times higher (95% CI, 5.5 to 12.2) in patients aged 65 years and older [14]. In patients with both RSV infection and asthma, the all-cause mortality rate during hospitalization and within 30 days post-discharge was reported to be 2.6%, while the in-hospital mortality rate was 4.3% [14].

2. South Korea

In South Korea, RSV is one of the acute respiratory viruses under sentinel surveillance by the Korea Disease Control and Prevention Agency (KDCA), and ranks as the third most common cause of ARIs (Table 3) [22,23]. In temperate regions like South Korea, RSV is a cause of seasonal respiratory diseases, exhibiting a 12-month seasonal cycle [23]. The data from 2015 to 2019 also reported that the peak of prevalence occurred between November and January [23].

According to a study conducted in South Korea, the annual incidence of RSV in the general adult population ranged from 1% to 7%, increasing to approximately 4% to 10% among the elderly and high-risk groups [2]. In a comparative study of adults hospitalized with RSV (n=97) or influenza (n=312), RSV patients were, on average, older (70 years old vs. 62 years old), more likely to be admitted from long-term care facilities (10.3% vs. 1.9%), had a higher prevalence of COPD (12.6% vs. 4.8%), and had higher incidence of pneumonia, secondary bacterial respiratory infections, and hypoxia [2]. Moreover, RSV patients had a significantly higher 20-day mortality rate than influenza patients (18.4% vs. 6.7%; hazard ratio, 2.32; 95% CI, 1.2 to 4.6)2. In another study, among 1,589 patients with severe community- acquired pneumonia, 3.4% were attributed to RSV and 8.1% to influenza. Among 1,276 cases of severe hospital-acquired pneumonia, RSV accounted for 3.8% and influenza accounted for 3.5% [2]. Immunocompromised (57.6% vs. 34.4%) and nosocomial infection (47.8% vs. 23.9%) were significantly more common in the RSV group; however, 90-day mortality rate was similar between the two groups (RSV 39.1% vs. influenza 40.5%) [2]. Another study comparing 368 patients with influenza and 184 patients with RSV found that although clinical symptoms were less frequent in RSV patients, they more often required oxygen therapy and had longer hospital stays, indicating more severe disease [3].

Among patients aged 75 years and older with RSV, hospitalization rate was 26.67%1. Among adult patients with ARI and pneumonia, the proportion of RSV-positive cases ranged from 1.21% to 7.52% [1]. The in-hospital mortality rate was approximately 7% to 10%, and ICU admission rates reached up to 40% [2].

Various respiratory diseases have been identified as a major underlying conditions among adults infected with RSV [23]. An analysis of 204 hospitalized RSV-positive patients from 2012 to 2015 revealed that the majority across all age groups had underlying conditions (85.0% in ages 19-49, 90.4% in ages 50-64, and 90.9% in those aged ≥65) [24]. Among these, pneumonia accounted for 57.8% [24], and two other studies reported that RSV patients had COPD (11.5% and 12.6%, respectively), asthma (3.4% and 6.6%, respectively), and non-COPD and non-asthma lung diseases, such as pneumoconiosis, interstitial lung disease, bronchiectasis, radiation pneumonitis, and fibrosis (7.0%) [25,26]. The prevalence of COPD and asthma among RSV patients in South Korea, as well as the RSV infection rates in patients with respiratory diseases, are presented in Table 4.

Similar to overseas findings, studies in South Korea have demonstrated a correlation between RSV infection and exacerbations of symptoms in patients with COPD and asthma. A retrospective study of 1,186 patients diagnosed with AE-COPD across 28 hospitals between 2015 and 2018 found that 6.4% of AE-COPD cases were attributed to RSV [27]. In a cohort study of Korean adults admitted to the ICU for severe pneumonia (median age of approximately 65 years), RSV was detected in 5.1% to 6.1% of cases1. RSV infection rates among patients with COPD and asthma ranged from 3.5% to 14.8% and 3.4% to 25.0%, respectively (Table 4) [23,25,26,28-32]. Furthermore, viral infections are also recognized as contributors to acute exacerbations of bronchiectasis [28]. Among 792 patients who visited the emergency room or were hospitalized due to bronchiectasis, viral infections were found in approximately 25% of patients, with RSV infections accounting for 13.1% of these cases [28].

RSV Vaccines

As previously mentioned, RSV infection can pose a significant burden, making prevention important; therefore, vaccination is recommended by several major authorities and guidelines (Table 5) [8-10]. In May 2023, the FDA approved RSVPreF3 OA, a recombinant F protein antigen vaccine, as the first vaccine for the prevention of RSV-LRTD in adults aged 60 years and older [5]. This was followed by the approval of the RSVpreF vaccine and, in 2024, mRNA vaccines [6].

1. RSVPreF3 OA vaccine

RSVPreF3 OA (Arexvy, GSK) is a vaccine that received FDA approval in 2023 for adults aged 60 years and older [5], followed by approval in 2024 for adults aged 50 to 59 years with an increased risk of RSV-LRTD infection [33]. RSVPreF3 OA consists of a pre-F recombinant F protein antigen and the ‘AS01’ adjuvant [34]. In the AReSVi-006 study and its sub studies, the prevention rate of RSV-LRTD with RSVPreF3 OA in adults aged 60 years and older was 82.6% during the first season (median follow-up period, 6.7 months) [34]. The cumulative prevention rate was 67.2% in the second season (median follow-up period, 17.8 months) and 62.9% up to the third season (median follow-up period, 30.6 months) [35].

2. RSVpreF vaccine

RSVpreF (Abrysvo, Pfizer), the second RSV vaccine approved by the FDA in 2023, is composed of recombinant surface proteins of RSV-A/B viruses [6,36]. In the first season (median follow-up period, 7.1 months), it showed an RSV-LRTD prevention rate of 65.1% in individuals with two or more symptoms, and 88.9% in those with three or more symptoms [37]. By the second season (median follow-up period, 17.6 months), the cumulative prevention rate was 58.8% for two or more symptoms and 81.5% for three or more symptoms [37].

3. mRNA-1345 vaccine

mRNA-1345 (MRESVIA, Moderna) is a lipid nanoparticle-encapsulated mRNA-based vaccine [38], and was approved by the FDA in 2024 as the third RSV vaccine for the prevention of RSV-LRTD in adults aged 60 years and older [6]. The RSV-LRTD prevention rates were 62.5% in individuals with two or more symptoms, and 61.1% in those with three or more symptoms in the first season (median follow-up period, 8.6 months) [39]. By the second season (median follow-up period, 18.8 months), the cumulative prevention rates were 47.4% for two or more symptoms and 48.4% for three or more symptoms [40].

4. South Korea and international clinical guidelines on RSV vaccination

Building on its 2023 recommendation for adults aged 60 years and older, the ACIP revised its guideline in 2024 to include both age- and risk-based recommendations [40]. This change, based on the evidence gathered over one RSV season, aims to maximize RSV vaccination rates in individuals most likely to benefit [40]. The updated recommendation advises a single dose of the RSV vaccine per year for all adults aged 75 years and older, as well as for adults aged 60 to 74 years who are at increased risk for severe RSV disease [40]. In 2025, the recommendation was further expanded to include all adults aged 75 years and older and high-risk individuals aged 50 to 74 years [8]. The 2025 GOLD also confirmed that RSV vaccines can prevent RSV-related diseases and reduce the likelihood of hospitalization [9]. It recommends that COPD patients receive a number of vaccines, including the RSV vaccine (evidence A), as well as influenza, pneumococcal, coronavirus disease 2019 (COVID-19), and Tdap vaccines [9]. Similarly, the GINA 2025 recommends RSV vaccination, along with pneumococcal, pertussis, influenza, and COVID-19 vaccines, in children, adults, and elderly asthma patients to prevent RSV-related upper and LRTDs and asthma exacerbations (Table 6) [10].

The 2024 COPD treatment guidelines of the Korean Academy of Tuberculosis and Respiratory Diseases also highlighted the association between RSV, the third most common respiratory virus after influenza and COVID-19, and AE-COPD, as well as the occurrence of cardiovascular complications in hospitalized elderly patients [41]. Since the RSV vaccine has been reported to be effective in preventing RSV-related diseases in the elderly, vaccination is recommended globally for individuals aged 75 years and older or those aged 60 years and older with immunosuppression or chronic heart/lung disease [8,41]. Accordingly, the guideline emphasizes the need to consider RSV vaccination particularly for elderly and high-risk individuals [41].

Discussion

In most patients, RSV infection presents as mild and non-specific symptoms, which lead to misdiagnosis as other respiratory infections, such as influenza [2,3,42]. Furthermore, the economic burden associated with RSV testing and the lack of awareness and understanding of the disease make diagnosis challenging [2]. Among the elderly, co-infection with other pathogens is not uncommon, which may further complicate the detection of RSV [42].

RSV ranks as the third most common cause of ARIs in South Korea [22], with an annual incidence rate of 1.7% in the general adult population, increasing to approximately 4% to 10% among the elderly and high-risk groups [2]. The hospitalization rate among RSV-infected patients is reported to be 26.67% [13], with the majority having multiple underlying diseases such as COPD, asthma, and lung diseases [3]. In addition, RSV infection was confirmed in patients hospitalized due to severe pneumonia or AE-COPD, asthma, or bronchiectasis [28]. Among adult patients with ARI and pneumonia, the mortality rate associated with RSV ranged from 1.21% to 7.52%, with an in-hospital mortality rate of approximately 7% to 10%, and up to 40% in patients admitted to the ICU [1]. Although RSV has a lower infection rate than influenza, it has been shown to result in more severe clinical outcomes, such as severe deterioration, transition to pneumonia, and death [3,25]. Thus despite its relatively low public awareness, RSV should be considered a clinically significant disease. In OA, the risk of severe RSV infection increases, potentially leading to worsening health status due to sequelae, increased frailty, and negative impacts on activities of daily living, autonomy, and independence [1,42]. As previously mentioned, there is no approved antiviral treatment for RSV in adults, and management is limited to supportive care [1]. Given the substantial disease burden and lack of specific therapies, prevention through vaccination is essential [1,13]. Accordingly, the ACIP recommends annual RSV vaccination for all adults aged 75 years and older, as well as for adults aged 60 to 74 years who are at increased risk for severe RSV disease, based on age and risk factors [8]. Furthermore, the GINA and GOLD clinical guidelines also recommend RSV vaccination among several vaccines for patients with COPD and asthma to prevent RSV-related diseases and exacerbations of underlying diseases [9,10]. In South Korea, the Korean Academy of Tuberculosis and Respiratory Diseases COPD clinical guideline emphasizes the need for an RSV vaccination strategy with a focus on the elderly and high-risk populations [41].

However, despite the risks and burden associated with RSV, research data from South Korea is lacking, with most studies limited to hospitalized patients, making it difficult to fully understand true burden of RSV infection. This may impede awareness and understanding of RSV infection among clinicians and the public, making RSV testing and treatment challenging. Another important limitation in understanding the true burden of RSV infection is the restricted availability and variable performance of diagnostic testing. Although rapid antigen detection tests for RSV are now available domestically, their diagnostic utility in adults—particularly in OA—is limited because of lower viral loads and reduced sensitivity compared with children. In contrast, reverse transcription polymerase chain reaction assays offer higher sensitivity and specificity, but their high cost and limited accessibility restrict their use mainly to hospitalized patients. Consequently, the true prevalence of RSV infection among adults in the community, especially outpatients with mild or moderate disease, remains difficult to ascertain.

To address these issues, we believe that extensive research on the burden of RSV infection is necessary. This should include prospective studies investigating the incidence and disease burden of RSV in outpatient population, comparative studies assessing the burden of RSV versus other major respiratory viruses such as influenza in patients with respiratory conditions, and research on the impact of underlying diseases on RSV severity. The findings from these studies would support nationwide public awareness campaigns targeting both the general population and RSV-infected patients, help establish educational programs to engage clinicians, and formulate prevention strategies. Support for including RSV vaccination in the National Immunization Program (NIP) should also be discussed, not only for individuals aged 65 years and older but also for those underlying diseases (e.g., cardiac disease, respiratory disease, etc.).

Furthermore, it should be noted that the currently available clinical data on RSV vaccine effectiveness extend for less than 3 years. As summarized in this manuscript, vaccine efficacy tends to decline over time, falling below 50% in subsequent RSV seasons. Considering that the cost of RSV vaccination has been reported to be more than five times higher than that of seasonal influenza vaccination, the argument for its immediate inclusion in the NIP may be premature. Therefore, a more balanced approach would be to recommend vaccination primarily for well-defined high-risk populations—such as OA and individuals with chronic cardiopulmonary or immunocompromising conditions—until additional long-term efficacy and cost-effectiveness data become available.

Conclusion

RSV is one of the most common causes of acute respiratory disease worldwide, and it presents a significant burden to population globally, including South Korea [1,2]. Various studies have shown that patients with underlying diseases, such as respiratory diseases, and the elderly are at an increased risk of RSV infection [13]. When infected, these individuals often experience worsening of major underlying respiratory diseases, along with higher rates of hospitalization and mortality [13]. Since there is no specific treatment for RSV infection, RSV vaccination can provide opportunities and benefits to prevent the associated burden on both the patients and the healthcare system [1]. As a result, various national and international guidelines are updating their recommendations for vaccination [8-10]. Ultimately, comprehensive efforts are urgently needed to raise awareness and understanding of the RSV burden among both clinicians and the public to effectively support the expansion of RSV vaccination.

Notes

Authors’ Contributions

Conceptualization: all authors. Methodology: all authors. Formal analysis: all authors. Data curation: all authors. Validation: all authors. Investigation: all authors. Writing - original draft preparation: Choi JY. Writing - review and editing: all authors. Approval of final manuscript: all authors.

Conflicts of Interest

Joon Young Choi is an early career editorial board member, Chin Kook Rhee is a deputy editor, Yong-Il Hwang is an associate editor, and Ji-Yong Moon is an editor of the journal, but they were not involved in the peer reviewer selection, evaluation, or decision process of this article. No other potential conflicts of interest relevant to this article were reported.

Funding

No funding to declare.

Table 1.

The prevalence of COPD among RSV-infected adults based on a random-effects model [14]

Study	Country	Age, yr	Events/Total	Proportion, % (95% CI)
Inpatient				30.84 (26.13-35.99)
Heterogeneity: I²=90%; τ²=0.3695; p<0.01
Outpatient
Barrett et al. (2020) [15]	USA	47-89	2/20	10.00 (1.23-31.70)
Duncan et al. (2009) [16]	USA	≥18	6/26	23.08 (8.97-43.65)
Juhn et al. (2023) [17]	USA	≥50	3/58	5.17 (1.08-14.38)
Walsh et al. (2013) [18]	USA	≥21	10/61	16.39 (8.15-28.09)
Korsten et al. (2021) [19]	The Netherlands, Belgium, UK	≥60	1/36	2.78 (0.07-14.53)
Heterogeneity: I²=53%; τ²=0.3235; p<0.07

COPD: chronic obstructive pulmonary disease; RSV: respiratory syncytial virus; CI: confidence interval.

Table 2.

The prevalence of asthma among RSV-infected adults based on a random-effects model [14]

Study	Country	Age, yr	Events/Total	Proportion, % (95% CI)
Inpatient				19.32 (14.97-24.58)
Heterogeneity: I²=94%; τ²=0.5083; p<0.01
Outpatient
Duncan et al. (2009) [16]	US	≥18	1/26	3.85 (0.10-19.64)
Juhn et al. (2023) [17]	US	≥50	6/58	10.34 (3.89-21.17)
Korsten et al. (2021) [19]	The Netherlands, Belgium, UK	≥60	2/36	5.56 (0.68-18.66)
Heterogeneity: I²=0%; τ²=0; p<0.52				7.50 (3.95-13.79)

RSV: respiratory syncytial virus; CI: confidence interval.

Table 3.

Reported annual positive rate of respiratory viruses from 2015 to 2019 in Korean Influenza and Respiratory Surveillance System (KINRESS) [23]

Year	Rhinovirus	Adenovirus	Human coronavirus	Respiratory syncytial virus	Influenza virus	Parainfluenza virus	Human meta-pneumovirus	Human bocavirus
2015	31.4%	12.2%	3.0%	17.8%	11.7%	11.9%	6.2%	5.8%
2016	24.7%	16.6%	6.6%	17.7%	13.6%	9.2%	5.6%	6.0%
2017	29.8%	9.2%	5.3%	20.1%	12.1%	11.1%	6.1%	6.4%
2018	23.6%	12.4%	6.5%	14.8%	21.5%	9.7%	6.4%	5.0%
2019	29.3%	15.0%	4.3%	11.7%	13.8%	12.6%	6.9%	6.3%

Table 4.

Rates of RSV-co-infection with respiratory diseases

Study	Study design	Disease	Age group	Respiratory diseases/Total RSV cases, %
Proportion of respiratory diseases among adults with RSV
Kwon et al. (2017) [25]	Retrospective	COPD	≥18 YOA	11/87 (12.6)
		Asthma	≥18 YOA	3/87 (3.4)
Park et al. (2017) [26]	Single-center,	COPD	≥18 YOA	26/227 (11.5)
	retrospective	Asthma	≥18 YOA	15/227 (6.6)
		Others	≥18 YOA	16/227 (7.0)
RSV-related respiratory complications
An et al. (2024) [23]	Multicenter, retrospective	AE-COPD, asthma	Asthma (≥18 YOA)	50/1,314 (3.4-5.0)
An et al. (2024) [23]	Multicenter, retrospective	AE-COPD, asthma	COPD (≥40 YOA)	50/1,314 (3.4-5.0)
Lee et al. (2022) [29]	Multicenter, observational	AE-COPD	≥40 YOA	42/1,186 (3.5)
Lee et al. (2022) [29]	Multicenter, observational	AE-COPD	Mean age: 73.78±9.22	42/1,186 (3.5)
Park et al. (2021) [28]	Single-center, retrospective	AE-bronchiectasis	Median age: 70 YOA	28/214 (13.1)
Jang et al. (2021) [30]	Single-center, retrospective	AE-COPD	Mean age: 76.5±7.9 YOA	16/108 (14.8)
Seo et al. (2017) [31]	Prospective	AE-asthma	≥18 YOA (adult)	RSV: 11/323 (3.4)
				In exacerbated cases: 8/259 (11.8)
				In stable cases: 3/64 (25.0)
Kwak et al. (2016) [32]	Single-center, retrospective	AE-COPD	Mean age: 69.2±11.0 YOA	12/78 (14.1)

RSV: respiratory syncytial virus; COPD: chronic obstructive pulmonary disease; YOA: years of age; AE: acute exacerbation.

Table 5.

Comparison of three RSV vaccines (as of June 2025)

Vaccine		RSVPreF3 OA [5,33-35]	RSVpreF [6,36,37]	mRNA-1345 [39,40]
Type		Recombinant RSV pre-fusion F protein adjuvanted with AS01E	Recombinant bivalent RSV-A and RSV-B pre-fusion F protein	mRNA expressing pre-fusion protein
Indication (US FDA)		Active immunization for the prevention of LRTD caused by RSV in:	1) Active immunization of pregnant individuals at 32 through 36 weeks gestational age for the prevention of LRTD and severe LRTD caused by respiratory syncytial virus (infants from birth through 6 months of age)	Active immunization for the prevention of LRTD caused by RSV in:
		1) Individuals aged 60 years and older	2) Active immunization for the prevention of LRTD caused by RSV in individuals aged 60 years and older	1) Individuals aged 60 years and older
		2) Individuals aged 50 to 59 years who are at increased risk for LRTD caused by RSV	3) Active immunization for the prevention of LRTD caused by RSV in individuals aged 18 to 59 years who are at increased risk for LRTD caused by RSV	2) Individuals aged 18 to 59 years who are at increased risk for LRTD caused by RSV
Dose		0.5 mL IM, once	0.5 mL IM, once	0.5 mL IM, once
Supplied		2 vials to be combined:	Kit for combination:	1 single dose pre-filled plastic syringe
		Vial of lyophilized antigen	Vial of lyophilized antigen
		Vial of adjuvant suspension	Pre-filled syringe of sterile water
			Vial adapter
Efficacy: RSV-associated LRTD (95% CI)/median follow-up period	Participants	In adults ≥60 years old	In adults ≥60 years old	In adults ≥60 years old
	Season 1	82.6 (57.9-94.1)^*	With ≥2 symptoms^†: 65.1 (35.9-82.0)	With ≥2 symptoms^‡: 62.5 (47.7-73.1)
		/6.7 months	With ≥3 symptoms^†: 88.9 (53.6-98.7)	With ≥3 symptoms^‡: 61.1 (34.7-76.8)
			/7.1 months	/8.6 months
	Season 2	67.2 (97.5% CI, 48.2-80.0)	With ≥2 symptoms: 58.8 (43.0-70.6)	With ≥2 symptoms^‡: 47.4 (35.0-57.4)
		/17.8 months	With ≥3 symptoms: 81.5 (63.3-91.6)	With ≥3 symptoms^‡: 48.4 (27.9-63.1)
			/17.6 months	/18.8 months
	Season 3	62.9 (97.5% CI, 46.7-74.8)^*
	Season 3	/30.6 months
FDA approved		May, 2023	May, 2023	May, 2024

^* RSV-LRTD, confirmed by reverse transcription polymerase chain reaction (RT-PCR), was defined as follows: the participant had experienced at least two lower respiratory symptoms or signs, including at least one lower respiratory sign for at least 24 hours, or had experienced at least three lower respiratory symptoms for at least 24 hours.

^† Reverse transcriptase-polymerase chain reaction-confirmed RSV illness with two or more, or three or more, respiratory symptoms within 7 days of symptom onset and lasting more than 1 day during the same illness.

^‡ LRTD symptoms included shortness of breath, cough, fever (≥100.0°F [≥37.8°C]), wheezing, rales, rhonchi, sputum production, tachypnea, hypoxemia (new oxygen saturation ≤93% or new or increasing use of supplemental oxygen), or pleuritic chest pain for ≥24 hours. In case of inability to fully assess other clinical parameters, radiologic evidence of pneumonia with RT-PCR- confirmed RSV infection could also be used to confirm RSV-associated LRTD.

RSV: respiratory syncytial virus; RSVPreF: respiratory syncytial virus prefusion F; OA: older adults; mRNA: messenger ribonucleic acid; FDA: Food and Drug Administration; LRTD: lower respiratory tract disease; IM: intramuscular; CI: confidence interval.

Table 6.

International and South Korea treatment guidelines on RSV vaccination

Guideline	Recommendation
ACIP 2025 [8]	All adults aged ≥75 years and adults aged 50-74 years who are at increased risk for severe RSV disease should receive a single dose of RSV vaccine^*.
ACIP 2025 [8]	A single dose provides protection for at least two RSV seasons.
GOLD 2025 [9]	RSV vaccination for individuals aged ≥60 years and/or with chronic heart or lung disease, as recommended by the CDC (Evidence A)
GINA 2025 [10]	RSV vaccines prevent RSV-related acute respiratory infection; an adjuvanted RSV-subunit vaccine reduced upper and lower respiratory tract disease in adults 60 years or older, including in those with underlying coexisting conditions such as asthma.
KATRD 2024 [41]	Recommendations for RSV vaccines are yet to be established in Korea, but it is necessary to approach vaccination with a focus on the elderly or high-risk groups.

^* Examples of risk factors that increase susceptibility to RSV infection include chronic cardiovascular disease, chronic respiratory disease, end-stage renal disease, chronic liver disease, severe obesity (body mass index ≥40 kg/m²), diabetes with complications or requiring insulin or sodium-glucose cotransporter-2 inhibitor treatment, neurological or neuromuscular diseases that weaken airway clearance or respiratory muscles, chronic blood disease, moderate or severe immunocompromise, in convalescence, and other chronic medical conditions that medical professionals determine may increase the risk of severe disease due to viral respiratory infection.

ACIP: Advisory Committee on Immunization Practices; RSV: respiratory syncytial virus; GOLD: Global Initiative for Chronic Obstructive Lung Disease; CDC: Centers for Disease Control and Prevention; GINA: Global Initiative for Asthma; KATRD: Korean Academy of Tuberculosis and Respiratory Diseases.

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