Respiratory syncytial virus (RSV) represents a major global public health challenge, with an especially high burden in low- and middle-income countries, many of which are located in Latin America. Worldwide, RSV is the leading cause of hospitalization in infants and young children due to lower respiratory tract infections (LRTIs). Beyond the acute illness, severe RSV disease is associated with substantial long-term respiratory morbidity, including recurrent wheezing and an increased risk of asthma later in childhood. These consequences underscore the significant clinical, social, and economic impact of RSV on children, families, and health systems, particularly in regions where healthcare access and surveillance infrastructure remain limited.
In recent years, major advances have been made in RSV prevention, including the availability of maternal vaccines and long-acting monoclonal antibodies that offer season-long protection for infants. However, access to these new tools remains uneven, and their implementation is particularly limited across much of Latin America, where the burden of disease is high and updated epidemiologic data are often scarce or inconsistent. Given these challenges, the Pediatrics chapter of ALAT undertook a mix in-person/virtual meetings to develop this comprehensive review to synthesize current knowledge on RSV epidemiology, consequences, and prevention in children across the region. RSV in Latin America causes a significant health burden among infants and young children. Disparities in healthcare access and preventive tools contribute to worse outcomes; recent advances in vaccines and treatments offer hope but ensuring equitable access and careful monitoring in low- and middle-income regions is crucial to reducing RSV-related illness and death.
IntroductionRSV is the main cause of hospitalizations for lower respiratory tract infections (LRTIs) in children, especially acute bronchiolitis and pneumonia [1]. In children under 5 years of age, annual estimates of the global impact of RSV-related lower respiratory tract infections (RSV-LRTIs) is around 33 million cases, with 3.6 million hospitalizations and 26,300 in-hospital deaths [1]. The highest incidence of hospitalization occurs in children under 6 months of age and approximately 99% of deaths occur in low- and middle-income countries (LMICs) [2–4]. Some groups are particularly vulnerable, such as premature infants, those born with congenital heart disease, bronchopulmonary dysplasia, genetic syndromes (especially Down syndrome) and neuromuscular diseases [2]. In contrast to the epidemiological changes observed in vaccine-preventable diseases in recent decades, the impact of LRTIs secondary to RSV has remained relatively unchanged for a long time. Thus, for example, the two most common viral agents of acute bronchiolitis continue to be RSV and rhinovirus. A recent meta-analysis [5] of 18 studies (n=6305 under 2 years of age) comparing the clinical course of RSV bronchiolitis vs. rhinovirus showed that RSV bronchiolitis was associated with a greater need for supplemental oxygen administration than rhinovirus (OR: 1.78, 95% CI: 1.04–3.02); but there were no significant differences in intensive care unit (ICU) admission, need for mechanical ventilation, presence of fever, wheezing, eosinophilia in peripheral blood, or family history of asthmatic parents between RSV bronchiolitis vs. rhinovirus; however, children with rhinovirus bronchiolitis had a higher personal history of dermatitis (OR: 0.60, 95% CI: 0.41–0.88).
In addition to the burden of LRTIs on hospitalizations and infant mortality, RSV-LRTIs in the early years of life are associated with increased respiratory morbidity in the medium and long term. In cohort studies in high-income countries, especially severe RSV disease has been associated with the development of wheezing or asthma during school-age age; however, there is limited data in low- and middle-income countries (LMICs) settings [3].
In recent years, the COVID-19 pandemic has led to notable epidemiological shifts. Several countries reported significant reductions in the incidence of RSV-LRTIs during periods of social distancing and other non-pharmacological interventions. However, data suggest a reversion to pre-pandemic patterns as these measures were relaxed [6–11]. Despite strong epidemiological evidence for the effectiveness of non-pharmacological measures to control the spread of RSV, sustaining these efforts is not always feasible. Consequently, a marked increase in RSV-LRTI incidence has been observed shortly after their discontinuation [12,13].
This ALAT consensus review aims to update the epidemiology, morbidity, management, and impact of pediatric RSV-LRTIs in Latin America and to summarize current and emerging prevention strategies. Methods: A mixed in-person/virtual process was used. A steering group set the scope and literature review. Multidisciplinary experts met via videoconference and in-person meetings to evaluate evidence, and draft statements. Two face-to-face workshops finalized the review and recommendations. Conflicts of interest were declared as needed. The final document underwent editorial integration, external review by a group of ALAT members and ALAT Director board.
Burden of RSV disease in the regionEpidemiology and impact of RSV-related lower respiratory tract infectionsAcute respiratory infections remain one of the leading causes of morbidity and mortality among children under five years of age worldwide [14]. Among viral agents responsible for LRTIs in infants and preschoolers, RSV stands out as the primary etiological agent, significantly contributing to disease burden. The PERCH study identified RSV as the virus with the highest attributable fraction (31%) for LRTIs in children under five, across nine countries in Africa and Asia. This finding was based on clinical evaluation, imaging, and molecular diagnostics. In comparison, other viral agents collectively accounted for 61.4% of infections [15]. Similar findings have been reported in Colombia, where a study involving 525 children under five with community-acquired pneumonia found that 72% had at least one viral pathogen identified, with RSV detected in 31.2% of cases [16]. Comparable prevalence rates have also been observed in studies from Costa Rica, Chile, Guatemala, Nicaragua, and Ecuador [17–21].
In a global burden of disease analysis based on 530 studies, Li et al. [1] estimated that, in 2019, RSV caused approximately 33 million infections in children under five, resulting in 3.6 million hospitalizations, 26,300 in-hospital deaths, and a total of 101,400 deaths attributable to RSV. The burden was particularly severe among infants under six months, accounting for 6.6 million infections, 1.4 million hospitalizations, and 45,700 deaths. Alarmingly, 97% of these deaths occurred in LMICs [1]. A systematic review by Ciapponi et al. [22], which included 156 studies from Latin America, found that the highest RSV prevalence occurred in children under one year of age (58%). Among subtypes, the prevalence of RSV-A and RSV-B was 52% and 34%, respectively. The incidence of RSV-LRTI was 15 per 100 symptomatic infants under two years of age and 22 per 100 in those under six months. ICU admission was required in 42% of hospitalized children under 24 months, with a mean ICU stay of 3.2 days (95% CI: 0.1–6.2), and mean general ward hospitalization of 6.5 days (95% CI: 4.7–8.3). Antibiotics were used in 47.4% of cases, and 13.6% required invasive mechanical ventilation. The case fatality rate was 0.6% (95% CI: 0.7–1.7) in children aged 0–2 years and 23% (95% CI: 7.6–52.2) in adults over 65 with risk factors [22].
High-risk pediatric groupsAmong 4738 children hospitalized for RSV-LRTI in Argentina, multivariable logistic analysis identified several independent risk factors for RSV-related mortality. These included moderate-to-severe malnutrition (OR: 3.69; 95% CI: 1.98–6.87), chronic neurologic disease (OR: 4.14; 95% CI: 2.12–8.08), congenital heart disease (OR: 4.18; 95% CI: 2.39–7.32), and age less than six months (OR: 1.99; 95% CI: 1.24–3.18) [23]. Children with risk factors, such as prematurity, experience higher attack rates and mortality. Another Argentine study by Ofman et al. involving 664 preterm infants reported an RSV hospitalization rate of 40.9 per 1000 (95% CI: 36.3–45.6), respiratory failure in 8.2 per 1000 (95% CI: 4.9–11.5), and a mortality rate of 0.8 per 1000 (95% CI: 0–1.7), with a case fatality rate of 1.8% [24]. A Chilean cohort study [25] involving 116 children hospitalized with RSV revealed that children with Down syndrome had significantly longer hospital stays than matched controls (6 vs. 4 days, p<0.001), even after adjusting for relevant comorbidities. Among children under one year, the difference was even more pronounced (11 vs. 5 days, p<0.0001). Children with Down syndrome also showed higher rates of ICU admission (43.1% vs. 22.4%, p=0.002), mechanical ventilation (36.2% vs. 13.7%, p=0.005), and use of antibiotics (64.2% vs. 43.8%, p=0.03) and corticosteroids (83% vs. 45.6%, p<0.0001). A global meta-analysis of 12 studies involving over 1.1 million children confirmed that those with Down syndrome had significantly higher risks for hospitalization (OR: 8.69; 95% CI: 7.33–10.30), mortality (OR: 9.4; 95% CI: 2.26–39.15), and longer hospital stays (mean difference: 4.73 days; 95% CI: 2.12–7.33). They were also more likely to require oxygen (OR: 6.53; 95% CI: 1.38–5.08), ICU admission (OR: 2.56; 95% CI: 1.17–5.59), mechanical ventilation (OR: 2.56; 95% CI:1.17–5.59), systemic corticosteroids (OR: 2.65; 95% CI: 1.38–5.08), and antibiotics (OR: 5.82; 95% CI 2.66–12.69) [26].
Adult burden of RSVThe burden of RSV in adults, particularly older adults, is also considerable. A population-based study by Savic et al. in high-income countries estimated that in 2019, RSV led to 5.2 million infections, 470,000 hospitalizations, and 33,000 in-hospital deaths among adults over 60 [27]. Notably, a study assessing the impact of passive immunization with nirsevimab in infants under six months found that it also conferred indirect protection to cohabiting older adults, reducing the RSV-attributable burden by 7–10% [28]. These findings underscore not only the significant disease burden in adults but also the potential broader benefits of passive immunization strategies – effects that have not yet been systematically evaluated in Latin America [29].
Economic burden of RSVEconomic data from Argentina, Brazil, Colombia, El Salvador, Mexico, Chile, Panama, and Puerto Rico show substantial direct costs associated with RSV, ranging from US$563 to US$19,706 per case, with ICU admissions representing the greatest proportion of expenses and pediatric emergency care the lowest [29,30]. In Argentina, hospitalization costs ranged from US$588 for general ward management to US$1557 for ICU care [31].
However, current cost estimates often fail to consider the indirect costs that are highly relevant from a societal perspective, as well as those associated with the long-term sequelae of RSV infection. Numerous longitudinal cohort studies have identified links between RSV infection and conditions such as recurrent wheezing, both non-atopic and atopic asthma, impaired pulmonary function, and obstructive sleep apnea [32–34].
These costs of recurrent wheezing and asthma should be included as relevant outcomes in cost-effectiveness and cost-utility studies to determine the comprehensive short- and medium-term impact of passive immunization strategies such as monoclonal antibodies (palivizumab, nirsevimab) and maternal vaccine. In a recent study, Dvornik et al. followed a cohort of 256 infants under 12 months with a history of severe RSV respiratory infection over a five-year period to assess the costs associated with recurrent wheezing. The study reported an average of five episodes of recurrent wheezing per child, with an estimated direct cost of $191 per episode, resulting in an average cumulative cost (including the primary infection) of $959 [35]. To date, palivizumab remains the only intervention shown to significantly reduce the incidence of recurrent wheezing one year post-infection (RR: 0.39; 95% CI: 0.35–0.44) and at three years (31.9% reduction), though it has not demonstrated a reduction in school-age asthma [36,37].
Disease heterogeneity and implications for managementGrowing evidence supports that acute bronchiolitis is a heterogeneous syndrome rather than a single disease entity. Recent trials have begun stratifying treatment by viral etiology and atopic predisposition [38]. Rosas-Salazar et al. found that RSV infection – regardless of severity – was associated with the onset of non-atopic asthma [34]. The absence of RSV infection was associated with a 26% reduction in the risk of developing non-atopic asthma, and it was estimated that up to 15% of asthma cases at age five could be prevented through available passive immunization strategies [34].
Additional complications linked to RSV have also been explored. For instance, an analysis from the Boston cohort revealed a twofold increased risk of obstructive sleep apnea within two years post-infection among children with a history of RSV bronchiolitis, compared to those without (OR: 2.09; 95% CI: 1.12–3.88) [33,39].
In a recent meta-analysis of 12 studies (n=1931), the efficacy of personalized bronchiolitis treatments based on viral cause was assessed [40]. Among six randomized trials evaluating systemic corticosteroids, two showed a significant benefit for RSV-negative patients. One study (n=313) found that oral prednisolone reduced hospital stay by at least one day (57.2±39.9h in RSV-positive vs. 19.7±31.5h in rhinovirus, p=0.002). Another found that oral dexamethasone allowed RSV-negative patients to be discharged 48h earlier (OR: 0.28; 95% CI: 0.09–0.92). However, the remaining four studies found no significant differences, highlighting the need for further randomized research to refine corticosteroid use based on the viral etiology of bronchiolitis [40].
RSV seasonalityRSV seasonality varies markedly across Latin America, with predictable winter peaks in temperate Southern Cone countries (e.g., Chile/Argentina) but less-regular or rain-linked circulation in tropical and equatorial settings (e.g., northern Brazil, Caribbean, parts of Central America), where activity may persist for many months or occur in multiple waves [41,42]. These latitude- and climate-associated patterns complicate timing for diagnostics, infection-prevention measures, and deployment of seasonal prophylaxis, and they have shown post-pandemic shifts in peak timing and intensity according to regional surveillance [41]. Recent multi-country analyses across the Americas and global syntheses consistently highlight stronger seasonality in temperate zones and higher variability in tropical/subtropical areas, reinforcing the need for country-specific calendars when planning testing and prevention [41,42].
Mortality and regional disparitiesMortality outcomes in Latin American middle-income countries appear to differ markedly from those in high-income settings. Findings from Central America underscore the critical mortality burden associated with risk factors in LMICs. In Guatemala, age, malnutrition, lack of breastfeeding, chronic comorbidities, and hypoxemia were key predictors of fatal outcomes [43]. In this study, among children <2 years, lower family income ( [43]. In Nicaragua, a prospective birth-cohort study from Managua, demonstrated a high incidence of symptomatic RSV illness in the first two years of life, accounting for a substantial proportion of medically attributed deaths (25–37.5%), with infants <3 months of age experiencing the most severe and life-threatening disease [44]. In Colombia, data from the National Institute of Health in 2019 estimated a mortality rate of 0.7% in children under five with RSV infection [45]. These findings align with data from the RSV-GOLD study, which reported mortality rates of 2% in children aged 0–60 months and 3.6% in infants aged 28 days to 6 months in low- and middle-income countries [1]. In Argentina, the mortality rate was estimated at 0.27%, with risk factors for severe disease similar to those in Colombia: age under six months, malnutrition, congenital heart disease, pneumothorax, and sepsis. In contrast, mortality rates in high-income countries remain below 0.1% [46]. Unfortunately, none of the currently available passive immunization strategies – approved monoclonal antibodies or maternal vaccination – have demonstrated a real-world reduction in mortality rates to date.
Diagnosis and management of RSV LRTIThe molecular diagnosis of RSV relies primarily on real-time reverse transcriptase polymerase chain reaction (RT-PCR), which is considered the gold standard due to its high sensitivity and specificity for detecting low viral loads and differentiating RSV subtypes. Confirming RSV through molecular testing is crucial not only to establish the etiological cause of disease, but also to inform the use of preventive strategies, guide patient isolation to reduce nosocomial transmission, and support clinical decision-making – particularly by avoiding unnecessary antibiotic use and reinforcing antimicrobial stewardship [47,48]. Early and accurate viral identification is especially important for protecting high-risk infants and children who are more likely to develop severe complications. In addition, diagnostic testing plays a fundamental role in generating epidemiological data that informs public health strategies, including surveillance, outbreak preparedness, and allocation of preventive interventions such as monoclonal antibody prophylaxis [47,49]. Although a wide range of diagnostic methods exist – from serology and viral culture to fluorescent antibody detection and PCR-based techniques – access to molecular testing in Latin America remains limited and highly unequal [22]. In addition to a lack of mandatory reporting or passive surveillance of RSV. In many public hospitals, RSV has no confirmation, and diagnosis still depends on seasonality and clinical symptoms. Other may have rapid antigen tests with suboptimal sensitivity, particularly in older infants or later in the disease course, resulting in underdiagnosis and misreporting. Structural barriers such as high costs, fragmented health systems, limited laboratory infrastructure, and delays in sample transport further complicate timely confirmation across the region. Figs. 1 and 2 show the proportion of respiratory samples positive for RSV across Latin American countries during two surveillance periods. Compared with the first period, the second period demonstrates higher RSV positivity and a broader geographic distribution, with more countries reaching or exceeding the 20% threshold. These changes may reflect increased testing and surveillance capacity or a true rise in RSV circulation. Substantial heterogeneity between countries was observed in both periods, with the later period characterized by pronounced increases in selected South and Central American countries (see Figs. 1 and 2) (source: https://dashboards.pahoflu.com/app/respiratory_viruses/).
Acute management of RSV disease in Latin America relies almost entirely on supportive care, as no antiviral or disease-modifying therapies are recommended for routine treatment of bronchiolitis [50–52]. Clinical assessment focuses on the degree of respiratory distress, feeding ability, oxygen saturation, and the presence of high-risk conditions such as prematurity, congenital heart disease, or chronic lung disease. Oxygen supplementation is initiated when saturations fall below approximately 90%, and hydration is maintained using oral, nasogastric, or intravenous routes depending on work of breathing and the infant's ability to feed. Where available, non-invasive respiratory support such as high-flow nasal cannula or CPAP is reserved for moderate to severe disease, while invasive mechanical ventilation is used in cases of impending or actual respiratory failure [53].
Diagnostic and therapeutic interventions with limited or no proven benefit are generally discouraged across regional and international guidelines. This includes routine chest radiographs, viral panels, blood tests, bronchodilators, systemic corticosteroids, nebulized hypertonic saline, and antibiotics – unless clinical findings suggest an alternative diagnosis or concomitant bacterial infection. These recommendations are consistent with evidence-based bronchiolitis guidelines from the American Academy of Pediatrics [52,53] and the Australia Guidelines [54], as well as local guidelines from Latin American countries that highlight significant practice variation but reaffirm the primacy of supportive care [50,51].
Long-term consequences after RSV-LRTIsRSV infections can range from mild upper respiratory tract symptoms to severe, life-threatening bronchiolitis and pneumonia. Nearly 70% of infants contract RSV within their first year, and by the age of two, almost all children (around 90%) have been infected. Of these, up to 40% experience an initial episode of LRTIs [55].
While the acute clinical effects of RSV, especially in severe cases, are well recognized, there is growing awareness of the virus's long-term consequences – most notably, its association with recurrent wheezing and asthma [34,56–61]. A longitudinal study tracking children under one year of age hospitalized with RSV-related LRTIs until the age of 18 found significantly higher rates of recurrent asthma or wheezing (39% vs. 9%), clinical allergies (43% vs. 17%), and perennial allergen sensitization (41% vs. 14%) compared to controls [62]. In the study by Sigurs et al. [63], multivariate analysis at seven years showed that RSV bronchiolitis was the strongest independent risk factor for asthma (OR: 12.7; 95% CI: 3.4–47.1). This association persisted at 18 years, where hospitalization for RSV was the most significant predictor of recurrent asthma/wheezing (OR: 6.2; 95% CI: 2.0–19.2) and asthma alone (OR: 7.2; 95% CI: 2.1–23.9) [62]. Similarly, a prospective cohort study showed that nearly half (48%) of children who developed severe RSV LRTIs in the first year of life were diagnosed with asthma by a physician at age seven [64]. Another study reported that 31% of preschool children with asthma had a history of severe bronchiolitis in early life [65].
Recently, the INSPIRE study which followed healthy full-term newborns for five years, found a 26% reduced risk of asthma in children who were not infected with RSV in their first year (a RR: 0.74; 95% CI: 0.58–0.94). It was the first study specifically designed to test the hypothesis that avoiding RSV infection in infancy reduces asthma risk [34]. In addition, the study also showed that asthma risk correlates with the severity of RSV infection – being lower in children with milder disease. Furthermore, this association may occur independently of atopy [66].
Recurrent wheezing can persist for years after an initial severe RSV infection, often necessitating ongoing medical care [67,68]. In fact, studies have shown that being born before the respiratory peak is associated with an increased risk of developing asthma in school-age age [69]. In another study, children born four months before the seasonal RSV peak had a 29% higher risk of asthma compared to those born 12 months before the peak [70]. A systematic review concluded that early RSV-LRTI is strongly associated with later respiratory issues, particularly transient wheezing, recurrent wheezing, and asthma within the first decade of life [71]. Additionally, early RSV-LRTI has been linked to reduced lung function [71]. However, a meta-analysis comparing infants with bronchiolitis caused by rhinovirus vs. RSV found that rhinovirus bronchiolitis was more strongly associated with later recurrent wheezing (OR: 4.11; 95% CI: 2.24–7.56) and asthma (OR: 2.72; 95% CI: 1.48–4.99) [72].
The SPRING study focused on late preterm infants (32–35 weeks gestational age) and found that those hospitalized for RSV had a significantly higher incidence of recurrent wheezing in the first six years of life, regardless of atopy history [73]. Similarly, the RISK study reported that 27.7% of RSV-hospitalized children experienced recurrent wheezing compared to 17.6% of those not hospitalized (OR: 1.8; 95% CI: 1.11–2.85). RSV infection in this group was also linked to increased healthcare usage in the year following infection, including emergency visits, outpatient care, and rehospitalizations [74,75].
Despite the clear association between RSV and asthma or wheezing, the causal relationship remains a topic of debate. In a double-blind, placebo-controlled trial in the Netherlands, preterm infants who received palivizumab had 61% fewer wheezing days and a 10% lower rate of recurrent wheezing compared to those given a placebo (11% vs. 21%) [76]. Later studies showed fewer parent-reported asthma-like symptoms in the palivizumab group, although physician-diagnosed asthma and lung function were similar between groups [61,70].
RSV infections early in life may also impair lung function. Several studies have reported reduced lung capacity and increased airway reactivity in school-aged children who experienced RSV-LRTIs in infancy [56,77–79]. For instance, a long-term study in Tucson found lower lung function in children who had RSV-LRTI before age three [56]. A 20-year Finnish follow-up found that 44% of children with RSV-LRTI in the first two years had at least one abnormal pulmonary function outcome, compared to 31% of controls (p<0.05) [77]. However, it remains unclear whether these impairments are directly caused by RSV or reflect pre-existing vulnerabilities [80].
Although direct evidence of causality is limited, the consistent association between early RSV-LRTI and later respiratory morbidity is well documented. These long-term effects go beyond medical concerns, impacting children's quality of life, family well-being, and contributing significantly to healthcare costs [81–83].
Non-pharmacological prevention strategiesNon-pharmacological strategies are essential for reducing RSV transmission, especially in settings where circulation is shaped by seasonal trends, population density, and broader social and environmental factors. A clear understanding of RSV transmission dynamics – ranging from predictable seasonal peaks to the heightened risk associated with crowded households and indoor exposures – underpins the development of effective community-level prevention measures. Protective behaviors such as breastfeeding, alongside caregiver education and community-based engagement, add meaningful layers of defense by supporting immunity, promoting early recognition of illness, and improving adherence to recommended practices.
These prevention efforts can be grouped into both general respiratory-virus precautions and RSV-specific approaches. Core measures include consistent hand hygiene, appropriate respiratory etiquette, maintaining distance during symptomatic periods, and routine cleaning of shared surfaces to limit fomite spread. When implemented together, these strategies provide a practical, accessible foundation for reducing RSV transmission across diverse communities.
Seasonal variability and transmission dynamicsRSV typically becomes endemic during colder months or rainy seasons in most regions. Nearly all children will be infected by the virus at least once before the age of two. While reinfections can occur throughout life, they generally lead to milder illness over time. Importantly, RSV is also a significant cause of respiratory illness in older adults – especially those over 65 or with pre-existing heart or lung conditions – with attack rates comparable to young children in non-institutionalized settings [84–86].
Although RSV outbreaks most commonly occur during winter, in tropical regions the virus may circulate year-round. Since long-lasting immunity is not typically established after reinfection, children under two without prior exposure remain at highest risk for severe illness. Consequently, this age group should be the primary target for preventive interventions [87].
Social and environmental risk factorsSeveral epidemiological studies highlight that close-contact environments are linked to an increased risk of severe RSV illness. Attending daycare, having older siblings, living in large families, or residing in overcrowded conditions all increase exposure and the likelihood of infection. Public transportation is also a risk factor due to its confined space and frequent surface contact. All these situations enhance the potential for transmission via droplets or contaminated surfaces (fomites) [87–93]. Although the exact transmission routes of RSV remain under discussion, preventive measures effective against similar respiratory viruses (e.g., influenza, parainfluenza, SARS) serve as a useful model. The most effective interventions include droplet and contact precautions. While RSV primarily spreads through close contact, airborne transmission over longer distances is also possible in some cases. This understanding supports the implementation of broader protective measures, especially for those at higher risk of severe disease [89,90,94,95].
Infection control and fomite transmissionRSV can remain viable on surfaces for several hours, making fomite transmission a significant concern. Thus, non-pharmacological prevention focuses on minimizing spread through droplets and contact. Such prevention approaches include isolation precautions, hand hygiene, and environmental cleaning and disinfection [96,97]. Physical distancing and the use of face coverings or masks should be considered in certain situations to reduce RSV transmission. Children susceptible to severe RSV illness may benefit greatly from these precautions. Preventing close contact between infected individuals and at-risk children is particularly important, as RSV can remain present in respiratory secretions for weeks after infection [96,98].
In healthcare settings, optimal prevention of nosocomial (hospital-acquired) RSV infections requires a multi-faceted approach, including contact isolation of RSV-positive patients, strict adherence to hand hygiene protocols, proper handling and disposal of contaminated materials, and masks use where indicated. Recently, several non-pharmacological prevention strategies have been developed and tested to protect high-risk infants from severe RSV lower respiratory tract infections and disease-associated hospitalizations [98,99].
While these measures are endorsed by agencies such as the Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO), specific evidence supporting their efficacy in individual (non-outbreak) cases remains limited. Still, these standard precautions incur minimal additional costs and are essential for preventing larger outbreaks, which can significantly strain healthcare resources [99–101].
Role of breastfeedingExclusive breastfeeding is universally recommended for newborns and has been shown to lower both the incidence and severity of RSV bronchiolitis [102–104]. In addition, breast milk prevents severe RSV disease by providing passive protection from mother to baby. Breast milk offers passive immunity through antibodies such as IgA, IgG, and IgM, transferred from the mother. Secretory IgA, the most abundant immunoglobulin in human milk, plays a key role in mucosal defense against RSV. Other bioactive components in breast milk, including lactoferrin and oligosaccharides, have demonstrated antiviral activity [102,103,105].
Education and community engagementEducation plays a critical role in RSV prevention. Parents, caregivers, and even educators at daycare centers should be informed about how RSV spreads and how it can be mitigated. Health education sessions during pediatric visits could teach children to wash hands frequently, cover coughs and sneezes properly, avoid touching the face and maintain distance from individuals with respiratory symptoms [106,107]. Such education can enhance adherence to preventive behaviors and reduce the spread of RSV within households and communities [106,107].
Emerging prevention strategies and public health interventionsPromoting active immunization in pregnant women and protecting the newborn through active and passive immunization are two novel strategies that can prevent RSV infection. These approaches could reduce both vertical (mother-to-child) and nosocomial transmission [108,109]. A recent study in Tucson found that maternal exposure to the RSV season during the third trimester significantly reduced the incidence of RSV-LRTI during the child's first year of life (9.1% vs. 13.2%, p=0.015). No such effect was seen with exposure during earlier trimesters [105].
In both high- and low-income settings, there are sustainable and cost-effective approaches to reducing RSV incidence, such as improving maternal health and nutrition, encouraging breastfeeding, and addressing environmental factors like pollution and housing conditions. Public awareness campaigns targeting passive smoking are especially important, as tobacco smoke can worsen RSV outcomes by increasing airway inflammation in young children [110–112]. In addition, addressing overcrowding and poor living conditions can also significantly reduce transmission risk. Public health awareness can guide policy development and improve adherence to both pharmacological and non-pharmacological interventions [113,114].
Pharmacological prevention interventionsImmunoprevention: monoclonal antibodiesRSV-specific prevention includes immunoprophylaxis with monoclonal antibodies (such as palivizumab, nirsevimab or clesrovimab) and immunization strategies, either maternal or pediatric. The recent introduction of maternal RSV vaccines and the long-acting monoclonal antibody nirsevimab or clesrovimab is expected to lead to significant epidemiological changes [115–121].
As precision medicine continues to guide advancements in pediatric healthcare, pharmacologic prevention has become a cornerstone in reducing the burden of respiratory syncytial virus (RSV). This includes both long-acting monoclonal antibodies and the growing portfolio of RSV vaccines. Understanding current and emerging guidance on these interventions – including Palivizumab and the newer long-acting antibodies such as nirsevimab and clesrovimab – is essential for shaping effective prevention strategies across both general pediatric populations and those at heightened risk [122]. Together, these tools represent a transformative shift in how clinicians and public health systems can proactively protect infants and young children from RSV.
The RSV fusion (F) protein is the primary target for vaccines, monoclonal antibodies, and antiviral therapies due to its critical role in viral entry into respiratory epithelial cells [123]. This protein is highly conserved across both RSV A and B subtypes and contains six antigenic sites capable of inducing robust neutralizing antibody responses [124,125]. Of these six key neutralization sites (I, II, III, IV, V, and Ø) on the pre-fusion (pre-F) form of the protein, sites Ø and V are the most exposed and, therefore, the most immunologically accessible. Antibodies targeting the pre-F conformation demonstrate superior neutralizing activity and binding strength compared to those targeting the post-fusion (post-F) form [126].
PalivizumabPalivizumab is a monoclonal antibody that specifically targets site II of the RSV F protein, neutralizing the virus and inhibiting membrane fusion [127,128]. Until recently, it was the leading prophylactic option for preventing severe RSV disease in high-risk infants. Key risk factors for severe RSV illness – which can lead to ICU admission, mechanical ventilation, or death – include prematurity (<35 weeks’ gestation), bronchopulmonary dysplasia, congenital heart disease with significant hemodynamic compromise, neuromuscular or chronic pulmonary disorders, airway malformations, genetic syndromes (e.g., Down syndrome), inborn errors of immunity, and severe respiratory conditions such as cystic fibrosis [129–131].
Approved in 1998, palivizumab significantly reduced RSV-related hospitalizations in high-risk infants. The pivotal IMPact-RSV study demonstrated a 55% overall reduction in RSV hospitalizations, including 59% in children with chronic lung disease, 47% in those born <32 weeks, and up to 80% in those born between 32 and 35 weeks’ gestation [127,132]. Subsequent studies, such as SENTINEL1, reported a 42% NICU admission rate and a 19% rate of mechanical ventilation among preterm infants (29–35 weeks) not receiving prophylaxis [133].
Other regional data reinforce these findings. A prospective study by Castillo et al. in Latin America reported RSV hospitalization rates of 2.9 per 100 patient-years with palivizumab – comparable to rates in clinical trials [134]. In a multicenter cohort study from Colombia involving 600 infants, only 1.8% were hospitalized with confirmed RSV despite receiving prophylaxis, and RSV-specific mortality was just 0.2%. Another Colombian cohort of 222 preterm infants found that those who required hospitalization had received fewer doses of palivizumab, suggesting a dose-dependent protective effect (p=0.049) [135,136].
To better prioritize prophylaxis in late preterm infants, several countries – including Canada, Spain, and the Netherlands – have developed risk stratification tools. These typically assess factors like birth timing relative to RSV season, household smoking exposure, and the presence of school-age siblings [137,138]. One such tool, the Risk Staging Tool (RST), classifies infants into low (≤19 points; 1.0% hospitalization risk), moderate (20–45; 3.3%), and high risk (50–56; 9.5%) groups [139]. In Latin America, where RSV circulates year-round, additional contextual risk factors include birth during RSV season (<12 weeks), low birth weight or growth restriction, limited breastfeeding (<2 months), daycare attendance, household crowding (≥4 members), smoking exposure, male sex, family history of asthma or eczema, low caregiver education, and young maternal age (<25 years). These factors can guide the decision to initiate prophylaxis in late preterm infants, whereas infants born between 29 and 32 weeks’ gestation often qualify for immunization based on gestational age alone due to their high disease burden [140].
Importantly, preventing or mitigating early RSV infection may also reduce the risk of developing recurrent wheezing or early childhood asthma. Several studies have demonstrated that palivizumab is associated with lower rates of wheezing in early life. For example, preterm infants who received prophylaxis had fewer wheezing episodes by age 3 compared to those who did not. In one study, palivizumab reduced wheezing by 2.7 days per 100 patient-days in infants aged 33–35 weeks versus placebo [37,76].
The MAKI trial, a randomized placebo-controlled study of 429 infants born at 32–35 weeks, showed a 41.9% reduction in wheezing at age 6 in the palivizumab group (11.6% vs. 19.9%). Similarly, the Japanese CREW study reported significantly lower rates of recurrent wheezing among palivizumab recipients (15.3%) compared to untreated infants (31.6%, p=.003) [78,141].
According to the American Association of Pediatrics 2014 guideline, updated in 2023 [142] palivizumab is recommended for:
- •
Infants born before 29 weeks gestation and under 12 months of age at the start of RSV season.
- •
Infants <32 weeks with bronchopulmonary dysplasia, especially those requiring oxygen, steroids, or diuretics during their second RSV season.
- •
Children under one year with neuromuscular or lung diseases.
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Immunocompromised patients under 24 months.
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Infants with congenital heart disease with hemodynamic significance.
Many Latin American countries have long adopted palivizumab as part of their national strategies, tailoring AAP recommendations to local needs and disease burdens (see Table 1). Based on these adaptations, children with Down syndrome – given their increased susceptibility – should also be included among those eligible for monoclonal antibody prophylaxis.
Administration and indications of palivizumab in Latin America.
| Gestational age | ≤26 | 26+1 to 28 | 28+1 to 29 | 29+1 to 30 | 30+1 to 32 | 32+1 to 34 | 34+1 to 35 |
|---|---|---|---|---|---|---|---|
| México | All | CCHS under 24 monthsBPD children younger than 12 months or younger than 24 months who have required treatment with oxygen, bronchodilators, diuretic, or inhaled steroid in the 6 months prior to the start of RSV season (November–March) | |||||
| Guatemala, Panamá, República Dominicana | All if they are younger than 12 months | BPD under 24 months if requiring oxygen, diuretic, or steroid | |||||
| Costa Rica | All if younger than 12 months at the beginning RSV season | CCHS if younger than 12 months at the beginning RSV season | |||||
| Colombia | All | With at least 2 risk factors for severe infection** | |||||
| Argentina | <29 weeks: birth weight <1000g with chronological age ≤12 months at the start of RSV season | <32 weeks: Birth weight <1500g with age chronological ≤6 months at the start of the RSV season | ≤34+6: chronological age <10 weeks at the start of RSV season with 2 risk factors*** | ||||
| Chile | All: <32 weeks and/or <1500g, or with twin brother <1500g | ||||||
| Perú | With BPD who have required treatment with oxygen, diuretics, steroids, or bronchodilators without acute respiratory infection | Chronological ≤6 months at the start of the RSV season | |||||
| Other indications independent of gestational age | |||||||
| Guatemala, Panamá, República Dominicana | CCHSNeuromuscular disease or lung disease that hinders clearance of secretions as in cystic fibrosis with evidence of chronic disease and malnutritionSevere immunocompromise in RSV season | ||||||
| Colombia | Younger than 12 months: BPD or post-prematurity respiratory disease with risk factors**, or in Down syndrome with CCHS, chronic lung disease, or immunity defect.Younger than 24 months: BPD on oxygen, steroid (oral or inhaled), or diuretics without prior immunoprophylaxis, severe chronic lung disease or with home ventilatory support, cystic fibrosis with severe lung disease and malnutrition, primary and secondary immunodeficiencies | ||||||
| Argentina | BPD: if it is <12 months or <24 months and required treatment with oxygen, diuretics, bronchodilators in 6 months prior to the start of the RSV season or discharged during itCongenital heart disease: if <12 months with CCHS or cardiomyopathy at the start of the RSV season, or <24 months on the transplant list or who received heart transplantation during the RSV seasonDown syndrome if you have CHD or prematuritySevere neuromuscular disease <24 months at high risk of ARI, respiratory failure, or impaired secretion clearanceSevere combined immunodeficiencyCongenital diaphragmatic hernia <24 months on home oxygen or moderate-to-severe PHTCystic fibrosis, lung malformations, or interstitial lung disease | ||||||
| Chile | CCHS*DBP with Risk Factors | ||||||
| Perú | In some Social Security accounts, it is approved for:All patients <29 weeks regardless of BPD diagnosisPatients <32 weeks and diagnosed with BPD up to 12 monthsCongenital heart disease up to 24 months | ||||||
Abbreviations: RSV: respiratory syncytial virus; PN: birth weight; GA: gestational age; PT: preterm; CHD: congenital heart disease; CCHS: hemodynamically significant heart disease; g: grams; RA: high risk; IRAB: acute respiratory infection; PHT: pulmonary hypertension; VAS: upper airway.
Risk factors considered in Chile: sibling in school, multiple births, exposure to smokers, overcrowding, low educational level of parents.
High-risk factors and/or risk conditions that predispose to serious infections and/or need for hospitalization in Colombia: attendance at daycare, living with children <5 years of age, not breastfeeding, exposure to tobacco smoke at home, mother who smokes during pregnancy, history of family atopy, maternal education at primary level or lower.
Governments and health ministries across Latin America that have not yet adopted any of the new long-acting monoclonal antibodies should transition promptly, as palivizumab is no longer recommended for routine use and will be discontinued effective December 31, 2025.
NirsevimabNirsevimab is a long-acting recombinant human monoclonal antibody designed to target the pre-fusion conformation of the RSV F (fusion) protein. Specifically, it is an IgG1 kappa monoclonal antibody that binds to the Ø antigenic site, blocking the F protein in its pre-fusion state and preventing viral entry into host respiratory epithelial cells. With an extended half-life, a single dose of nirsevimab provides protection for at least five months. Clinical studies have shown that serum antibody concentrations remain above the 90% efficacy threshold even at 151 days post-administration [143].
Nirsevimab has demonstrated a significant impact in reducing both medically attended RSV illness and RSV-related hospitalizations [144]. In the initial phase of the MELODY trial – a randomized clinical study comparing nirsevimab with placebo in term and late preterm infants – nirsevimab reduced medically attended RSV disease by 74.5% at 150 days [95% CI: 49–87]. When the trial was extended due to changes in RSV circulation during the COVID-19 pandemic, a 76.8% reduction in RSV-related hospitalizations was observed [144,145]. The HARMONIE study, a pragmatic trial conducted in France, Germany, and the UK, included infants up to 12 months old (gestational age ≥29 weeks) entering their first RSV season. Participants received either a single dose of nirsevimab or standard care (no prophylaxis). Nirsevimab showed 83.2% efficacy in preventing hospitalization for RSV-associated lower respiratory tract infections (95% CI: 67.8–92.0) [146] In the MEDLEY study, the safety and efficacy of a second dose of nirsevimab (200mg) were evaluated in infants with congenital heart disease or chronic lung disease, comparing outcomes to those who received palivizumab. Nirsevimab demonstrated a safety profile like palivizumab, with comparable efficacy [147].
In September 2023, Galicia (Spain) launched the NIRSE-GAL population-based study to assess real-world effectiveness of nirsevimab in preventing RSV hospitalizations. Early data showed an 89% reduction in hospital admissions among infants under six months (95% CI: 85–93), with a number needed to treat (NNT) of 25 to prevent one hospitalization [148]. In Latin America, Chile was the first country to implement widespread immunization with nirsevimab. Within four months, a significant decrease in RSV-related hospitalizations – ranging from 86% to 90% – was reported compared to previous seasons. Notably, Chile achieved 98% coverage in newborns and 90% in infants under one year, with no RSV-related deaths in children under 12 months reported during this period (Ministry of Health of Chile) [149,150].
In a recent systematic review and meta-analysis, Soudani et al. examined 16 observational studies (totaling approximately 141,550 infants) across Spain, Italy, the United States and France to assess the real-world effectiveness of nirsevimab in preventing RSV-LRTI in infants [151]. They found that nirsevimab was associated with substantial reductions in risk, approximately an 84.5% reduction (95% CI: 73.6%–90.9%) in hospitalization for RSV-LRTI, an 85.9% reduction (95% CI: 13.2%–97.7%) in admissions to intensive care, and an 87.1% reduction (95% CI: 70.2%–94.4%) in ventilatory support use. For less severe settings, they estimated reductions of 75.8% (95% CI: 40.4%–92.7%) for primary-care visits and 87.9% (95% CI: 70.3%–95.1%) for emergency-department visits due to RSV-LRTI [151]. Importantly, the authors did not observe a meaningful difference in effectiveness between infants born during the RSV season and those born out of season, nor between preterm and term infants – though they noted that the available data on very preterm infants remain limited.
In Chile, the National Nirsevimab Immunization strategy (NIRSE-CL) evaluated 154,173 infants born between 1 October 2023 and 30 September 2024, of whom 145,087 received nirsevimab, achieving high coverage across both the catch-up and seasonal cohorts [152]. After adjustment for demographic and clinical factors, nirsevimab demonstrated an effectiveness of 76.41% (95% CI: 72.57–79.72) against RSV-related LRTI hospitalizations and 84.94% (95% CI: 79.47–88.95) against RSV-related ICU admissions; effectiveness against all-cause LRTI and all-cause hospitalization was 66.50% (95% CI: 61.97–70.50) and 47.90% (95% CI: 44.35–51.21), respectively [152]. The counterfactual modelling indicated 30.05 averted RSV-LRTI hospitalizations per 1000 immunized infants, corresponding to an NNI of 35 to prevent one RSV-LRTI admission [152]. Economic evaluations based on Chilean national datasets from 2019 to 2023 showed that a nirsevimab strategy yields substantial cost-savings and reduces healthcare utilization by preventing seasonal LRTI surges [153]. Additional modelling work similarly identified nirsevimab-centered prevention as a cost-effective strategy for protecting infants from RSV disease in Chile [154]. Collectively, these data indicate that nirsevimab is a highly effective, virologically stable, and economically advantageous intervention for RSV prevention in Latin America.
As for dosage, the recommendation is 50mg in children under 5kg of body weight and 100mg in those weighing more than or equal to 5kg. The dose is unique in infants in their first RSV season and should always be prioritized for infants under 6 months of age. It is recommended to give one dose to all children under 8 months of age who are born during the season or who are entering their first RSV season. In addition, it will be applied to children between 8 and 19 months who are at higher risk of contracting severe disease from RSV, shortly before the start of the season. In Chile, prophylaxis with nirsevimab is extended up to 24 months of age and is applied universally, regardless of underlying risk factors.
Despite encouraging clinical outcomes, cost-effectiveness data for Latin America remains limited. A Colombian study analyzed cost-effectiveness thresholds based on quality-adjusted life years (QALYs) and suggested that to be considered cost-effective at thresholds of US$4828, US$5128, and US$19,992 per QALY, the corresponding acceptable price per dose of nirsevimab would need to be US$21.88, US$25.04, and US$44.02, respectively [155].
ClesrovimabClesrovimab is a long-acting monoclonal antibody designed to provide passive immunity against RSV by targeting site IV on the RSV F protein, a conserved epitope present on both A and B strains [156]. By binding this site, clesrovimab neutralizes both RSV A and B strains and prevents the conformational changes required for viral entry into host respiratory epithelial cells. It differs from RSV the RSV antibodies palivizumab (site II) and nirsevimab (site Ø) (Table 2).
Administration and indications of nirsevimab.
| Country | Target population | Indications |
|---|---|---|
| Chile | Newborns and infants as of 1/10/2023 | - Universal for all children during their first RSV season, including infants benefited by the Ricarte Soto Law for palivizumab up to 24 months:1. Preterm infants (less than 35 weeks or <2500g at birth).2. Twin brothers of premature babies.3. Infants with hemodynamically significant congenital heart disease or cyanotic heart disease. |
| Argentina | Infants in their first season of RSV | - Nirsevimab approved for:1. Healthy, full-term or premature infants.2. Children up to 24 months of age vulnerable to severe RSV illness through their second RSV season. |
Efficacy and safety in healthy infants were evaluated in the pivotal CLEVER phase 2b/3 trial, which enrolled 3614 healthy preterm and full-term infants entering their first RSV season and compared one intramuscular 105-mg dose of clesrovimab or placebo. Patients were followed for 150 days for the primary endpoint of RSV-associated medically attended LRTI. In this study, clesrovimab significantly reduced medically attended RSV disease by 60.4% (95% CI: 44.1%–71.9%), and RSV-associated hospitalizations by 82% (95% CI: 66.6%–92.6%) compared to placebo. Safety outcomes were favorable: adverse events were similar between groups and no new safety signals were identified [121].
In the August 28, 2025 issue of MMWR Morbidity and Mortality Weekly Report, Moulia et al. report that the Advisory Committee on Immunization Practices (ACIP) recommends the newly licensed monoclonal antibody clesrovimab, as an alternative to nirsevimab for preventing severe RSV-LRTI in infants aged <8 months who are born during or entering their first RSV season and whose mothers did not receive RSV vaccination [120].
Immunoprevention: maternal vaccinationRSV exists in multiple subtypes, with types A and B being most prevalent. While the G protein varies between subtypes, the F protein is conserved and antigenically shared. Consequently, the F protein, especially in its prefusion (pre-F) form, is the primary target for vaccines. This protein shifts quickly from a pre-fusion to a more stable post-fusion conformation after infecting host cells [123]. Pre-F differs from post-F in two antigenic sites, the first having six of them (Ø, I, II, III, IV and V) and the second having only four (I, II, III and IV). Therapeutics like palivizumab target the shared site II, while more potent neutralizing antibodies – especially in adult populations – predominantly target Ø and V, which are exclusive to the pre-F structure [123,157].
Vaccines based on the post-F structure have shown limited efficacy. For instance, a phase 2b trial by Fallon et al. found no significant difference in RSV-related acute respiratory infections among elderly patients who received a post-F vaccine versus placebo [158]. This highlights the superior neutralizing potency of agents like nirsevimab, which targets the Ø site and is approximately 100 times more potent in vitro than palivizumab [123].
Currently, there are two pre-F vaccines approved by regulatory agencies such as the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) for the prevention of RSV infection. In 2023, two pre-F-based RSV vaccines were approved for older adults in the U.S. and Europe. The Pfizer vaccine ABRYSVO received FDA approval in May 2023 for individuals over 60 years and in August 2023 for pregnant women between 32 and 36 weeks of gestation to prevent RSV-LRTI in infants aged 0–6 months. The European Medicines Agency (EMA) approved ABRYSVO in July 2023 for maternal immunization during 24–36 weeks of pregnancy and for older adults [159–163].
ABRYSVO is a bivalent vaccine containing pre-F RSV-A and RSV-B proteins in equal amounts. In pregnant individuals, it induces antibodies that cross the placenta, providing passive immunity to infants in their first six months of life [161].
Two major clinical trials underpin the approval of ABRYSVO for use during pregnancy. A phase 2b trial in healthy pregnant women aged 18–49 years, vaccinated between 24 and 36 weeks of gestation, evaluated safety and immunogenicity using doses of 120μg or 240μg, with or without aluminum hydroxide, compared with placebo [164]. The study found no significant differences in adverse events among groups, while vaccinated mothers demonstrated markedly higher RSV-A and RSV-B neutralizing antibody levels, with greater placental transfer in those who received the formulation without aluminum hydroxide [164]. A large phase 3 randomized, double-blind trial by Kampmann et al. enrolled 7358 pregnant women across 18 countries, including Argentina and Chile, who received a single 120μg dose or placebo between 24 and 36 weeks of gestation [161]. This trial showed 81.8% efficacy against severe RSV-associated lower respiratory tract infection within 90 days after birth and 69.4% efficacy within 180 days. Although adverse events were not significantly increased, a trend toward more preterm births and hypertensive disorders was observed among vaccinated participants [161]. As a precaution, the FDA authorized use between 32 and 36 weeks and required post-marketing safety monitoring [165].
Post-marketing data have continued to support the vaccine's safety and effectiveness. A Japanese study reported 100% efficacy against severe RSV disease at 90 days and 75.1% at 180 days, with similar rates of maternal adverse events in vaccine and placebo groups and a lower preterm birth rate in the vaccinated group (3.2% vs. 6%) [166]. In the United States, surveillance from the 2023–2024 season documented a 4.1% preterm birth rate among vaccinated mothers, consistent with expected historical baselines [167]. Additionally, a retrospective cohort study from two New York hospitals (September 2023–January 2024) found no significant association between maternal RSV immunization and adverse perinatal outcomes, including preterm birth, with an adjusted odds ratio of 0.87 (95% CI: 0.62–1.20) [168,169].
Following Food and Drug Administration (FDA) approval and CDC endorsement in 2023, the United States implemented a complementary strategy integrating maternal vaccination with monoclonal antibody use. This includes seasonal administration – vaccinating pregnant women between September and January, ideally one to two months before RSV season – for optimal protection and cost-effectiveness; co-administration with Tdap, influenza, and COVID-19 vaccines without regard to timing; and ongoing evaluation of the need for boosters in subsequent pregnancies as more safety and effectiveness data accumulate [170]. Consistent with evidence from U.S. and European regulatory bodies, the Pan American Health Organization recommends the use of ABRYSVO in pregnant women between 32 and 36 weeks of gestation for any Latin American or Caribbean country electing to introduce the vaccine [167].
In Argentina, the vaccine was approved in September 2023 for pregnant women (32–36 weeks) and adults over 60. In December 2023, it was added to the national immunization program, effective from March 1, 2024, in preparation for the southern hemisphere winter [168]. Likewise, on April 10, 2024, in Uruguay, as part of a combined strategy, the National Advisory Commission on Vaccination (CAV) considered introducing the pre-F RSV vaccine into its immunization program in pregnant women between 32 and 36.6 weeks of gestational age [169,170].
Currently, this vaccine is endorsed in more than 30 countries, including Canada, the United States, the United Kingdom, the United Arab Emirates, countries belonging to the European Union, Bahrain, Saudi Arabia, Macau, Australia, Hong Kong and Japan. In Latin America, it is approved in Argentina, Costa Rica, Panamá and Uruguay (Table 3).
Administration and indications of the RSV vaccine in Latin America.
| Argentina | September 2023Pregnant women between 32 and 36 weeks of gestational age for the prevention of lower respiratory tract disease and severe respiratory infection caused by RSV in infants from birth to 6 months of age |
| Uruguay | In April 2024, as part of a combined strategy, the National Advisory Commission on Vaccination (CAV) considered introducing the RSVpreF vaccine into its immunization program in pregnant women between 32 and 36.6 weeks of gestational age. |
| Brasil | In April 2024, Brazil's National Health Surveillance Agency (ANVISA) approved passive protection against lower respiratory tract disease caused by RSV in infants from birth to 6 months of age. Maternal immunization during pregnancy at 24–36 weeks of gestational age |
| Costa Rica | In June 2025 Ministry of Health, in coordination with the Costa Rican Social Security Fund (CCSS) introducing the RSVpreF vaccine for pregnant women between 32 and 36 weeks of gestational age. |
| Colombia | In November 2025 Ministry of Health introducing the RSVpreF vaccine into its immunization program in pregnant women between 28 and 36 weeks of gestational age. |
Note: Maternal immunization with RSV is designed to protect infants during the first 6 months of life, which is when the risk of hospitalization for RSV is highest. Administer between the 32nd and 36th week of gestation.
Current expert guidance emphasizes that all infants should receive protection against RSV-LRTI through at least one of the available preventive strategies [122,171]. Leading public health bodies, state that effective protection can be achieved through maternal RSV vaccination during pregnancy, which provides passive antibody transfer to the newborn, or through direct infant immunoprophylaxis with a new long-acting monoclonal antibody – either nirsevimab or clesrovimab – administered prior to or during the RSV season [120]. These approaches serve the same preventive goal, and no single method is broadly favored; instead, the most appropriate option is guided by factors such as timing, availability of products, and individual clinical circumstances. Together, these recommendations highlight a coordinated strategy to ensure that all infants receive effective protection against severe RSV disease during their first season of risk [172,173].
LimitationsThis consensus reflects expert opinion informed by available data, but it is not a systematic review and relies on studies of variable quality from across Latin America. Although the panel included diverse clinicians and researchers, it may not fully represent all regional perspectives or health-system realities. The consensus process used a mixed in-person and virtual format, rather than a formal Delphi method or structured evidence-grading system, which may limit the rigor and consistency of agreement. Additionally, because RSV epidemiology and preventive strategies are evolving rapidly, the recommendations may require updating as new evidence emerges.
ConclusionRSV poses a substantial health burden among infants and young children globally. While it is a concern in all regions, the impact is especially severe in developing countries, including many across Latin America. Variations in disease outcomes between high- and low-income countries are likely influenced by disparities in access to healthcare, resource availability, living conditions, and the affordability of preventive tools such as monoclonal antibodies for high-risk groups.
Recent advances in RSV prevention, including the development and broader distribution of vaccines and treatments, mark a promising shift in the fight against the virus. This progress brings with it a critical responsibility, particularly for health systems in Latin America, to ensure that these innovations reach the most vulnerable populations. Ensuring equitable access to newly approved vaccines and monoclonal antibodies in low- and middle-income countries is essential. Additionally, careful monitoring and evaluation of these interventions will be vital to maximize their impact and reduce RSV-related illness and death.
FundingThe study was funded by AstraZeneca. The sponsors did not play any part in the study and did not participate at any stage of the development of these guidelines. None of the authors was paid for their participation in the preparation of this update or consensus.
Conflict of interestsNone of the authors declare no real or perceived conflict of interest with the preparation or presentation of this consensus.
