Estimated Respiratory Syncytial Virus-Related Hospitalizations and Deaths Among Children and Adults in Spain, 2016-2019

Respiratory syncytial virus immunization with nirsevimab: Acceptance and satisfaction assessment in infants and risk groups in the region of Murcia (Spain)

Respiratory syncytial virus (RSV) is a leading cause of respiratory infections in infants under two years of age, often resulting in bronchiolitis and pneumonia, which contribute to high hospitalization rates. The recent approval of nirsevimab, a long-acting monoclonal antibody, has provided an immunization alternative for infants, addressing the substantial burden of RSV. This study aimed to evaluate acceptance and satisfaction among parents or legal guardians of infants who were candidates for immunization with nirsevimab in the Region of Murcia (Spain) during the 2023-2024 campaign. A cross-sectional survey, encompassing 1692 parents of immunized infants and 219 of non-immunized infants, revealed a high acceptance rate for nirsevimab, with 87% of parents indicating willingness to immunize a future child and 86.6% willing to recommend it. Concerns about safety and side effects were the primary reasons for hesitation among parents who did not immunize their infants. These findings underscore the importance of enhancing educational efforts in future campaigns to address safety concerns, thereby supporting broader RSV immunization coverage in the pediatric population.

Disease burden of influenza in Spain: A five-season study (2015-2020)

Influenza accounts for 30% of the total morbidity and mortality in the European Union. However, the specific burden in different European countries is largely unknown, and more research is needed to ascertain the reality of this disease. In this retrospective study, we analyzed the burdens of hospitalization, intensive care unit (ICU) admission and in-hospital mortality in Spain over five seasons (2015-2020) via publicly available Minimum Basic Datasets (MDBS). The data revealed that influenza had a major impact in Spain, with approximately 29,000 hospitalizations, 2,200 ICU admissions, and 1,600 deaths each season. In this period, approximately 7.8% of those hospitalized required ICU admission, and 5.7% died in the hospital due to influenza, with wide differences in these parameters depending on the season due to the virological characteristics of the major circulating viruses. More than 60% of those hospitalized were over 65 years of age, and approximately 82% of those who died were elderly, demonstrating that the greatest burden of hospitalization and mortality is centered on this age group. The annual direct cost of influenza was approximately €128 million per season, with more than 80% of this cost centered on people over 45 years of age.

Estimated Incidence Rate of Specific Types of Cardiovascular and Respiratory Hospitalizations Attributable to Respiratory Syncytial Virus Among Adults in Germany Between 2015 and 2019

BACKGROUND

RSV incidence in adults is frequently underestimated due to non-specific symptomatology, limited standard-of-care testing, and lower test sensitivity compared to infants. We conducted a retrospective observational study to estimate RSV-attributable incidence of specific types of cardiorespiratory hospitalizations among adults in Germany between 2015 and 2019.

METHODS

Information on hospitalizations and the number of people at risk of hospitalization (denominator) was gathered from a Statutory Health Insurance database. A quasi-Poisson regression model accounting for periodic and aperiodic time trends and virus activity was fitted to estimate the RSV-attributable incidence rate (IR) of four specific cardiovascular hospitalizations (arrhythmia, ischemic heart diseases, chronic heart failure exacerbations, and cerebrovascular diseases) and four specific respiratory hospitalizations (influenza/pneumonia, bronchitis/bronchiolitis, chronic lower respiratory tract diseases, and upper respiratory tract diseases).

RESULTS

The estimated RSV-attributable IRs of hospitalizations generally increased with age. Among estimated cardiovascular hospitalizations in adults aged ≥ 60 years, arrhythmia and ischemic heart diseases accounted for the highest incidence of RSV-attributable events, followed by chronic heart failure exacerbation, with annual IR ranges of 157-260, 133-214, and 105-169 per 100,000 person-years, respectively. The most frequent RSV-attributable respiratory hospitalizations in adults aged ≥ 60 years were estimated for chronic lower respiratory tract diseases and bronchitis/bronchiolitis, with annual IR ranges of 103-168 and 77-122 per 100,000 person-years, respectively.

CONCLUSIONS

RSV causes a considerable burden of respiratory and cardiovascular hospitalizations in adults in Germany, similar to other respiratory viruses (e.g., influenza and SARS-CoV-2). This highlights the need to implement effective prevention strategies, especially for older adults.

Influence of kindergarten dormitory bed layout on the proximity propagation characteristics of exhaled pollutants

Kindergarten dormitories are indoor napping areas where preschool children spend extended periods nearby, making them high-risk environments for the transmission of respiratory diseases. To understand the transmission characteristics of respiratory pollutants, particularly CO2 and simulated cough aerosols between adjacent beds, two common bed layouts in kindergartens were investigated: three beds of staggered height (TBSH) and three beds of uniform height (TBUH). The experiments measured CO2 and PM2.5 concentrations (using liquid aerosols generated by an ultrasonic nebulizer as surrogates for cough particles) in the breathing zone of mannequins under different ventilation modes (on and off) and sleeping postures (lying face up and on the right side). The results showed that when ventilation was off, CO2 concentration near the head of each bed reached nearly 1,000 ppm within 60 min. When ventilation was on, CO2 concentration was diluted to ambient levels within 3.3 min. However, when the ventilation was on, aerosols exhibited different propagation characteristics compared to CO2. While CO2 was rapidly diluted, aerosols accumulated downstream and formed high-concentration zones at adjacent downstream beds. These findings visualize the potential aerosol transmission pathways between beds in kindergarten dormitories and highlight the limitations of using CO2 as an aerosol transmission tracer. The study found that increasing bed heights along the ventilation airflow direction effectively reduced downstream aerosol concentrations and compensated for the insufficient horizontal distance in kindergarten dormitories. Kindergarten design standards should consider local dilution efficiency in the breathing zone, and bed layouts should be integrated with the ventilation system to ensure air velocities exceed 0.01 m/s near the head, thereby reducing the residence time of pollutants in the breathing zone.

Estimated Incidence of Hospitalisations and Deaths Attributable to Respiratory Syncytial Virus Infections in Adults in Australia Between 2010 and 2019

BACKGROUND

Respiratory syncytial virus (RSV) morbidity and mortality in adults are often underestimated due to nonspecific symptoms, limited standard-of-care testing and lower diagnostic testing sensitivity compared with children. To accurately evaluate the RSV disease burden among adults in Australia, we conducted a model-based study to estimate RSV-attributable cardiorespiratory hospitalisation incidence and mortality rate.

METHODS

A quasi-Poisson regression model was used to estimate RSV-attributable cardiorespiratory, respiratory and cardiovascular events, using weekly hospitalisation and mortality data from 2010 to 2019, accounting for periodic and aperiodic time trends and viral activity and allowing for potential overdispersion. The time-series model compared the variability in confirmed RSV events alongside variability in all-cause cardiorespiratory events identified from ICD-10-AM codes to estimate the number of RSV-attributable events, including undiagnosed RSV-related events.

RESULTS

RSV-attributable incidence of cardiorespiratory hospitalisations increased with age and was highest among adults ≥ 65 years (329.5-386.6 cases per 100,000 person-years), nine times higher than in adults 18-64 years. The estimated incidence of RSV-attributable respiratory hospitalisations in adults ≥65 years (219.7-247.8 cases per 100,000 person-years) was 35-fold higher than in adults 18-64 years. RSV-attributable deaths accounted for 4% to 6% of cardiorespiratory deaths in adults ≥ 65 years, with RSV-attributable mortality rates ranging from 65.6 to 77.6 deaths per 100,000 person-years and respiratory mortality rates ranging from 20.3 to 24.0 deaths per 100,000 person-years, both 70-fold higher than in adults 18-64 years.

CONCLUSIONS

This study identified substantial RSV-associated morbidity and mortality among Australian adults and is the first study to report RSV-attributable mortality rates for Australia that account for untested events.

Incidence of RSV-related hospitalizations for ARIs, including CAP: Data from the German prospective ThEpiCAP study

BACKGROUND

RSV is a leading cause of ARI, including CAP, in older adults. Data available often underestimate RSV-related ARI incidence. We estimated RSV-related ARI hospitalization incidence from a prospective CAP study, adjusting for undiagnosed RSV infections due to nasopharyngeal/nasal swab testing only.

METHODS

Active surveillance of adult CAP hospitalizations in Germany was conducted between 2021-2023. Nasopharyngeal/nasal swabs were RSV-tested, and age-group specific proportions were applied to calculate RSV-related CAP incidence. This was divided by the CAP proportions among RSV-related ARI hospitalizations (from multispecimen study) to extrapolate RSV-related ARI rates.

RESULTS

Among 1040 radiologically confirmed CAP cases, 3.7% tested RSV-positive via nasopharyngeal/nasal swab, corresponding to 7.8% after adjusting for underdetection. For 18-59 and ≥60 years, adjusted RSV-related CAP hospitalization rates (95% CI) were 4.9 (1.8-10.9) and 115.6 (78.8-163.6); adjusted RSV-related ARI hospitalization rates were 19.8 (6.8-50.1) and 401.6 (260.7-609.3) per 100,000, respectively. Within 30 days of an RSV-related CAP admission, 18.2% of those ≥65 years died, and 11.1% and 36.4% had cardiovascular events among those 18-64 and ≥65 years, respectively.

CONCLUSIONS

Older adults in Germany experience a high burden of RSV-related ARI hospitalizations, including CAP, underscoring RSV vaccination's potential utility for this population.

Hospitalization cost estimates of respiratory syncytial virus and influenza infections in adults in Spain, 2016-2019

Respiratory syncytial virus (RSV) is increasingly a recognized cause of severe respiratory infection among adults. This retrospective observational study compared the costs of RSV and influenza hospitalizations in adults aged ≥18 years admitted to the Spanish National Healthcare System between 2016 and 2019. Mean costs per hospitalization episode were compared using a multivariable log-gamma generalized linear model adjusted by age, risk group and calendar year. Total annual hospitalization costs were estimated from population incidence rates (for RSV we used model-based rates reported in a published study due to the substantial under-ascertainment of cases) and the mean cost per episode. ICD-10 codes identified a total of 11,662 adults hospitalized with RSV and 79,319 with influenza. The mean length of stay was longer for RSV than for influenza in low-risk patients aged 60-79 years, moderate-risk patients (those with chronic medical conditions) aged ≥50 years and in high-risk (those with immunocompromising conditions) patients aged <80 years. There were no differences in intensive care unit (ICU) admission (except for higher admission in high-risk RSV patients aged 70-79 years), ICU stay or in-hospital case fatality rate. Mean costs per hospitalization episode were also similar: RSV €3870 (95 % CI 3773-3942) vs influenza €3888 (95 % CI 3836-3931). Total annual costs for RSV-attributable hospitalizations were estimated at M€194, twice than that of influenza (M€83). Annual costs increased by 11 % over the study period for RSV and by 47 % for influenza. In 2019, adults aged ≥60 years and ≥ 70 years contributed 91 % and 82 %, respectively, of the total RSV-attributable hospitalization costs in adults. RSV has a significant economic burden to the Spanish National Healthcare System, likely greater than influenza. Efficacious RSV vaccines and antivirals have the potential for high public health impact.

Clinical and economic inpatient burden of respiratory syncytial virus (RSV) infections in children < 2 years of age in Germany, 2014-2019: a retrospective health claims analysis

BACKGROUND

Respiratory syncytial virus (RSV) is a common cause for severe lower respiratory tract infections (LRTI) in children < 2 years of age in Germany - though little is known about the clinical and economic burden of RSV in children with and without risk factors per month of life.

METHODS

In a retrospective health claims analysis, we identified RSV inpatient cases between 2014 and 2019. We assessed incidence rates, mortality rate, healthcare resource utilization, associated direct costs per case and excess costs for 30, 90 and 365 days after hospital admission matched to a control group. The outcomes are reported separately for the first and second year of life (i.e., for infants and toddlers) and were stratified by month of life, preterm and risk status (i.e., presence of underlying disease: chronic respiratory or cardiac disease, immunosuppression, neurological diseases, diabetes, conditions originating in the perinatal period).

RESULTS

RSV-attributable hospital incidence rate was higher in infants (30.25/1,000) than toddlers (14.52/1,000), highest in the first three months of life (44.21/1,000), in infants born preterm (64.76/1,000) or with any underlying disease (54.85/1,000). Mortality rate was also higher for infants (0.08/1,000) than toddlers (0.04/1,000). Mean 30-day excess costs ranged from 2,953 € for infants born full-term at no risk, hospitalized for 5 days, to 6,694 € for infants born extremely premature, hospitalized for 7 days.

CONCLUSION

In Germany, the clinical and economic burden of RSV is substantial, especially in the most vulnerable population, that is, very young infants, those born premature and/or those with an underlying disease.

Burden and Economic Impact of Respiratory Viral Infections in Adults Aged 60 and Older: A Focus on RSV

Background/Objectives: Respiratory syncytial virus (RSV) represents a significant cause of acute respiratory infections (ARIs) in adults aged 60 years and older, often leading to severe clinical outcomes and high healthcare costs. This study aimed to evaluate the clinical and economic burden of RSV compared to other ARIs, focusing on specific age groups, comorbidities, and demographic factors. Methods: A retrospective observational study was conducted using the electronic medical records of adults aged ≥60 years hospitalized for ARIs, including RSV, in Spain. Direct costs related to hospitalizations, intensive care unit (ICU) admissions, and treatments were analyzed. The study also assessed demographic, clinical, and comorbidity-related factors influencing the economic burden. Results: RSV infections resulted in significantly higher direct costs compared to other ARIs, particularly in patients aged 70-80 years. Comorbidities such as asthma and smoking history were associated with increased costs in RSV cases. Although ICU costs were comparable between groups, hospitalizations for RSV required longer stays and more intensive treatments, amplifying the overall economic burden. Differences in costs by age and sex highlighted the need for tailored clinical management strategies. Conclusions: RSV poses a substantial economic and clinical burden on adults aged 60 years and older, particularly in those with comorbidities. Preventive measures, such as vaccination, could reduce healthcare costs and improve outcomes in this vulnerable population. These findings support the inclusion of RSV vaccines in immunization programs, especially in aging populations like Spain, to alleviate healthcare pressures during peak respiratory disease seasons.

Estimating the burden of RSV- and influenza-associated hospitalizations, ICU admissions, and deaths across age and socioeconomic groups in New York State, 2005-2019

Background

Multiple prophylactic products are now available to protect against respiratory syncytial virus (RSV) in different age groups. Assessing the pre-intervention burden of RSV infections across various severity levels and risk groups is crucial, as it provides a baseline for evaluating the impact of these products.

Methods

We obtained monthly time series data on hospitalizations, intensive care unit (ICU) admissions, and deaths by age group, ZIP code, and cause for New York state from 2005 to 2019. Socioeconomic status (SES) of the ZIP codes was classified using supervised principal component analysis (PCA). We estimated the incidence of hospitalizations, ICU admissions, and deaths attributable to RSV and to influenza using hierarchical Bayesian regression models. Additionally, we assessed severity, defined by ICU admission and mortality risks, as well as recording fraction (i.e., percent of estimated virus-associated hospitalizations recorded as being due to the specific virus), stratified by age, SES, and over time.

Results

The estimated annual incidence of RSV-associated hospitalizations and ICU admissions were highest in infants under 1 in the low SES group (2,240 [95% credible interval (CrI): 2,200-2,290] hospitalizations and 330 [95% CrI: 320-350] ICU admissions per 100,000 person-years). The incidence of RSV-associated deaths was highest among adults ≥85 years old (61 [95% CrI: 49-74] per 100,000 person-years). In contrast to RSV, the burden of influenza was greatest in age groups ≥65 years. The risk of ICU admission varied by patients' age and SES, and the mortality risk increased dramatically with age for both pathogens (RSV: 11.9% [95% CrI: 9.6-14.3%], influenza: 14.4% [95% CrI: 13.1-15.6%] among ≥85 year age group). Incidence varied by epidemic year and season, and we observed an increasing recording fraction of RSV among all age groups over the study period.

Conclusions

RSV and influenza contribute significantly to the burden of hospitalizations, ICU admissions, and deaths, particularly among infants and older adults. Although the recording fraction of RSV increased over the study period, it remains lower, particularly for adults. Our findings reveal a disparity in hospitalization burden by SES, particularly among younger age groups.

Economic burden of children hospitalized with respiratory syncytial virus infection in Spain, 2016-2019

This retrospective observational study aimed to quantify the costs associated with hospitalized respiratory syncytial virus (RSV) in children <18 years admitted to the Spanish National Healthcare System between 2016 and 2019 and contrast them with the costs of unspecified bronchiolitis/bronchitis/pneumonia (UBP) and influenza. The mean cost per hospitalization episode was reported by age group, risk category and prematurity. Total annual hospitalization costs were calculated from population incidence rates and the mean cost per episode. A total of 41,934 children were hospitalized with RSV, 70,160 with UBP and 8525 with influenza during 2016-2019. The highest incidence of hospitalization for RSV, UBP, and influenza occurred among infants <6 months. The mean cost per episode was highest for RSV cases aged <6 months with at least one risk factor (€4760 high vs €2827 low risk), while the mean cost ranged from €3704-4352 for high-risk and €2687-3475 for low-risk children of other ages, and from €4300-44,594 for preterm infants. In the 0-5 months age group, the mean cost per episode for UBP was €4189 and €2666 for high and low risk, and for influenza it was €3134 and €2081, respectively; while the mean cost of co-infected RSV-influenza cases was €4809 and €2887, respectively. The mean total annual estimated cost for RSV for children aged 0-17 years was €39.3 M based only on reported cases, rising to €53.8 M if we correct for under-diagnosis and all RSV-attributable cases are considered. In contrast, the mean total annual cost for influenza was €5.9 M. Compared to influenza, RSV has a substantially higher economic burden; nevertheless, the Spanish immunization schedule recommends influenza vaccine between 6 and 59 months of age and RSV monoclonal antibody only for those aged <6 months. RSV immunization is still to be implemented in older children, considering that 37 % of RSV hospitalized patients were aged ≥6 months.

[Epidemiological characteristics of respiratory syncytial virus infection in children in Nanchang and its correlation with climate environmental factors]

OBJECTIVES

To explore the epidemiological characteristics of respiratory syncytial virus (RSV) infection in children in Nanchang and its correlation with climate environmental factors.

METHODS

The clinical data were collected from children with acute respiratory infection in Nanchang who were tested for RSV at Jiangxi Provincial Children's Hospital from January 2019 to December 2023, along with climate environmental data for the same period. The epidemiological characteristics of RSV and their correlation with climate environmental factors were investigated.

RESULTS

A total of 178 127 children underwent RSV testing from January 2019 to December 2023, with a positive detection rate of 8.35% (14 873/178 127). The positive detection rate in males was 8.92% (10 137/113 660), which was higher than that in females (7.35%, 4 736/64 467). The differences in RSV positive detection rates among different age groups were statistically significant (P<0.001), with the highest rate observed in the 0 to <3 months age group (14.38%, 3 328/23 142). Peaks in RSV positive detection occurred during winter and spring periods in 2019, 2020, and 2022, while in 2023, it occurred in spring and summer periods, with no seasonality noted in 2021. The RSV positive detection rate showed a positive correlation with average humidity, average atmospheric pressure, monthly PM2.5, and monthly carbon monoxide levels (P<0.05), while it showed a negative correlation with average wind speed, average temperature, and maximum 8-hour ozone levels (P<0.05).

CONCLUSIONS

In Nanchang, the RSV positive detection rate in children with acute respiratory infection is higher in males than in females. Among children of all age groups, the infants aged 0 to <3 months have the highest detection rate of RSV. RSV infection predominantly occurs in winter and spring periods. Lower temperatures, lower wind speeds, higher humidity, and elevated levels of PM2.5 and carbon monoxide may increase the risk of RSV infection in children.

Annual public health and economic burden of medically attended respiratory syncytial virus illnesses among US adults

BACKGROUND

Respiratory syncytial virus (RSV) is a common cause of lower respiratory tract disease (LRTD) among adults and can lead to serious morbidity and mortality; however, evidence on the magnitude of the public health and economic burden of adult RSV-LRTD is limited. This study was undertaken to project annual clinical outcomes and economic costs of medically attended RSV-LRTD among US adults, and to identify subgroups responsible for a disproportionate share of disease burden.

METHODS

Clinical outcomes of RSV-LRTD were projected for subgroups of US adults defined by age and comorbidity profile (with vs. without chronic/immunocompromising medical conditions) based on corresponding population sizes, episode (disease) rates, and case-fatality rates. Economic costs comprised medical (i.e., direct) costs and non-medical (i.e., indirect) costs of RSV-LRTD, and were generated based on numbers of episodes and unit costs in relation to setting of care, age, and comorbidity profile.

RESULTS

Among 265 million US adults aged ≥18 years in 2023, 6.5 million medically attended episodes of RSV-LRTD were projected to occur including 349,260 requiring hospitalization, 357,892 requiring an emergency department visit (not leading to hospitalization), and 5.8 million requiring other ambulatory care. Direct costs ($15.2 billion) and indirect costs ($9.7 billion) were projected to total $25.0 billion. Persons aged 60-99 years accounted for 31 % of the adult population and over 50 % of the economic burden of RSV-LRTD, while adults aged <60 years with chronic/immunocompromising medical conditions accounted for 10 % of the population and 27 % of the economic burden.

CONCLUSIONS

Annual burden of RSV-LRTD among US adults-especially older adults and those of all ages with underlying medical conditions-is substantial. Preventive measures, such as recently approved RSV vaccines, have the potential to yield important improvements in public and patient health, and to reduce the economic burden of RSV-LRTD from the US healthcare system and societal perspectives.

Impact of Respiratory Syncytial Virus (RSV) in Adults 60 Years and Older in Spain

Background/Objectives: Respiratory illnesses frequently lead to hospitalization in adults aged 60 and older, especially due to respiratory viral infectious (RVI). This study investigates hospitalization patterns and characteristics of RVI at HM Hospitals from October 2023 to March 2024; Methods: We retrospectively explored hospitalizations of patients aged 60 years and older with RVIs, gathering data on demographics, clinical profiles, comorbidities, and treatments. Outcomes included hospitalization, ICU admissions, and mortality, and independent factors associated with outcomes were identified using a multi-state model; Results: From October 2023 to March 2024, from a total of 3258 hospitalizations, 1933 (59.3%) were identified as positive for RVIs. Overall, SARS-CoV-2 was the most prevalent (52.6%), followed by influenza (32.7%), and RSV (11.8%). Most RVI involved single infections (88.2%). Hospitalization rates increased with age for SARS-CoV-2 (333.4 [95% CI: 295.0-375.2] to 651.6 [95% CI: 532.1-788.4]), influenza (169.8 [95% CI: 142.6-200.7] to 518.6 [95% CI: 412.1-643.1]), and RSV (69.2 [95% CI: 52.2-90.0] to 246.0 [95% CI: 173.8-337.5]), with SARS-CoV-2 showing the highest rate, followed by influenza and RSV. In the multi-state model, RSV infection significantly increased ICU admission risk (HR: 2.1, 95%, p = 0.037). Age on admission (HR: 1.1, 95%, p < 0.001) and Charlson score (HR: 1.4, 95%, p = 0.001) were associated with transitioning from admission to death. ICU to death risks included age at admission (HR: 1.7, 95%, p < 0.001); Conclusions: RVI in adults 60 years and older are associated with high hospitalization and mortality rates, primarily driven by influenza and SARS-CoV-2, followed by RSV. Age and comorbidities significantly impact disease severity, emphasizing the need for targeted prevention and management strategies for RSV in this vulnerable population.

Respiratory Syncytial Virus Risk Profile in Hospitalized Infants and Comparison with Influenza and COVID-19 Controls in Valladolid, Spain, 2010-2022

INTRODUCTION

We aimed to describe the risk profile of RSV infections among children aged ≤ 24 months in Valladolid from January 2010 to August 2022 and to compare them with influenza and COVID-19 controls.

METHODS

We conducted a retrospective cohort study of all laboratory-confirmed RSV, influenza, and COVID-19 infections. We analyzed risk factors for RSV hospitalization and severity (length-of-stay ≥ 8 days, intensive-care-unit admission, in-hospital death or readmission < 30 days) and compared severity between hospitalized RSV patients vs. influenza and COVID-19 controls using multivariable logistic regression models.

RESULTS

We included 1507 patients with RSV (1274 inpatient), 32 with influenza, and 52 COVID-19 controls. Hospitalized RSV (mean age 5.3 months) and COVID-19 (4 months) were younger than influenza (9.1 months) patients. Sixteen percent of patients had RSV within the first month of life. Most infants did not have comorbidities (74% RSV, 56% influenza, and 69% COVID-19). Forty-one percent of patients with RSV and influenza were coinfected vs. 27% COVID-19 (p = 0.04). Among RSV, hospitalization risk factors were prematurity (adjusted OR 3.11 [95% CI 1.66, 4.44]) and coinfection (2.03 [1.45, 2.85]). Risks for higher severity were maternal smoking (1.89 [1.07, 3.33]), prematurity (2.31 [1.59, 3.34]), chronic lung disease (2.20 [1.06, 4.58]), neurodevelopmental condition (4.28 [2.10, 8.73]), and coinfection (2.67 [2.09, 3.40]). Breastfeeding was protective against hospitalization (0.87 [0.80, 0.95]) and severity (0.81 [0.74, 0.88]), while complete vaccination schedule was protective against severity (0.51 [0.27, 0.97]). RSV had 2.47 (1.03, 5.96) higher risk of experiencing any severe outcome compared to influenza and did not show significant differences vs. COVID-19.

CONCLUSIONS

RSV hospitalizations were more frequent and severe than influenza, while severity was comparable to the early pandemic COVID-19. Currently, both influenza and COVID-19 vaccines are included in the maternal and childhood Spanish immunization schedule between the ages of 6 and 59 months. RSV monoclonal antibody is recommended for ≤ 6 months but a third of patients were aged 6-24 months. Maternal RSV vaccination can protect their children directly from birth and indirectly through breastfeeding.

RSV Risk Profile in Hospitalized Adults and Comparison with Influenza and COVID-19 Controls in Valladolid, Spain, 2010-2022

INTRODUCTION

We aimed to describe the risk profile of respiratory syncytial virus (RSV) infections among adults ≥ 60 years in Valladolid from January 2010 to August 2022, and to compare them with influenza and COVID-19 controls.

METHODS

This was a retrospective cohort study of all laboratory-confirmed RSV infections identified in centralized microbiology database during a 12-year period. We analyzed risk factors for RSV hospitalization and severity (length of stay, intensive care unit admission, in-hospital death or readmission < 30 days) and compared severity between RSV patients vs. influenza and COVID-19 controls using multivariable logistic regression models.

RESULTS

We included 706 RSV patients (635 inpatients and 71 outpatients), and 598 influenza and 60 COVID-19 hospitalized controls with comparable sociodemographic profile. Among RSV patients, 96 (15%) had a subtype identified: 56% A, 42% B, and 2% A + B. Eighty-one percent of RSV patients had cardiovascular conditions, 65% endocrine/metabolic, 46% chronic lung, and 43% immunocompromising conditions. Thirty-six percent were coinfected (vs. 21% influenza and 20% COVID-19; p =  < .0001 and 0.01). Ninety-two percent had signs of lower respiratory infection (vs. 85% influenza and 72% COVID-19, p =  < .0001) and 27% cardiovascular signs (vs. 20% influenza and 8% COVID-19, p = 0.0031 and 0.0009). Laboratory parameters of anemia, inflammation, and hypoxemia were highest in RSV. Among RSV, being a previous smoker (adjusted OR 2.81 [95% CI 1.01, 7.82]), coinfection (4.34 [2.02, 9.34]), and having cardiovascular (3.79 [2.17, 6.62]), neurologic (2.20 [1.09, 4.46]), or chronic lung (1.93 [1.11, 3.38]) diseases were risks for hospitalization. Being resident in care institutions (1.68 [1.09, 2.61]) or having a coinfection (1.91[1.36, 2.69]) were risks for higher severity, while RSV subtype was not associated with severity. Whereas RSV and influenza patients did not show differences in severity, RSV patients had 68% (38-84%) lower odds of experiencing any severe outcome compared to COVID-19.

CONCLUSIONS

RSV especially affects those with comorbidities, coinfections, and living in care institutions. RSV vaccination could have an important public health impact in this population.

Burden of Disease Due to Respiratory Syncytial Virus in Adults in Five Middle-Income Countries

Respiratory syncytial virus (RSV) is an important cause of severe respiratory disease in older adults. Understanding the disease burden is crucial for guiding vaccination policy and raising disease awareness. We estimated the burden of RSV hospitalizations and deaths in adults in five middle-income countries: Argentina, Brazil, Chile, Mexico, and Malaysia. Hospital discharge and death statistics due to any respiratory disease (ICD-10 codes: J00-99) from 2010 to 2022 were obtained. The RSV attributable burden on hospitalizations and deaths by age group was determined for 2019 using previously published estimates. Latin American countries showed distinct annual peaks in respiratory-related hospitalizations and deaths during winter months that were absent in Malaysia. Among ≥20-year-olds in 2019, there were 14,604 RSV-attributable hospitalizations nationally in Argentina, 44,323 in Brazil, 4529 in Chile, 7416 in Malaysia, and 8651 in Mexico, and 60-74% in ≥65-year-olds. There were also 3518 RSV-attributable deaths in Argentina, 9115 in Brazil, 801 in Chile, 704 in Malaysia, and 3806 in Mexico 79-88% in ≥65-year-olds. Incidences of RSV-attributable hospitalizations in ≥75-year-olds ranged between 256.3 and 294.3 per 100,000 population, and deaths between 33.6 and 112.9 per 100,000 population. RSV is associated with a substantial disease burden beyond pediatric age groups, and preventive vaccines could have a major impact on this burden, especially in older adults.

Occurrence of Central Nervous System Complications of Respiratory Syncytial Virus Infections: A Systematic Review with Meta-Analysis

An increasing base of evidence suggests that respiratory syncytial virus (RSV) infections may be associated with neurological complications. In accord with the PRISMA statement, we performed a systematic review and meta-analysis on the occurrence of encephalitis and encephalopathy associated with documented RSV infections. PubMed, Embase, and Scopus databases were searched for eligible observational studies published up to 10 April 2024. Raw data included the occurrence of RSV infections among cases of encephalitis and/or encephalopathy and cases of encephalitis and/or encephalopathy among series of RSV infections. Data were pooled in a random effects model. Case reports were also collected, and their data pooled as a cumulative series. Heterogeneity was assessed using the I2 measure, while reporting bias was assessed by means of funnel plots and regression analysis. A total of 15 studies for a total of 7719 RSV infections and 1631 cases of encephalitis were analyzed. Moreover, 27 case reports and case series were retrieved, for a total of 84 individual cases of encephalitis/encephalopathy occurring during a documented RSV infection. A pooled prevalence of 2.20 cases of encephalitis/encephalopathy per 100 RSV cases (I2 = 99%) was calculated, while a prevalence of RSV infections among cases of encephalitis/encephalopathy was estimated to 3.53 per 100 cases for studies on respiratory specimens (I2 = 48%) and 0.37 per cases on central nervous system (CNS) specimens (I2 = 0%). Detection of RSV within the CNS was relatively rare (17.86% of pooled case reports), being associated with male gender (adjusted odds ratio [aOR] 5.021, 95% confidence interval [95%CI] 1.104 to 22.831) and recovery with long-term sequelae (aOR 5.699, 95%CI 1.152; 28.183). Case fatality ratio was estimated to be 0.43 per 100 cases on observational studies and 10.71% in case reports, a difference likely due to publication bias. In summary, RSV represented a not frequent but notable cause of encephalitis/encephalopathy in adults and children. The paucity of available studies not only recommends a cautious appraisal of our results but stresses the clinical significance of future studies on incident cases of encephalitis and/or encephalopathy.

How Does the Burden of Respiratory Syncytial Virus Compare to Influenza in Spanish Adults?

BACKGROUND

Respiratory syncytial virus (RSV) and influenza infections cause significant annual morbidity and mortality worldwide in at-risk populations. This study is aimed at assessing hospital burden and healthcare resource utilization (HRU) of RSV and influenza in adults in Spain.

METHODS

Data were obtained from the Projected Hospitalisation Database of inpatient episodes (ages: younger adults 18-50 and 51-64 years; older adults 65-74, 75-84, and ≥ 85 years) during 2015, 2017, and 2018 in Spanish public hospitals. Incidence, mean hospitalization, and HRU assessments, including length of stay (LOS), intensive care unit (ICU) usage, and age-standardized mortality rates, were collected and stratified by age group, with analyses focusing on the adult population (≥ 18 years old).

RESULTS

Mean hospitalization rate in the population across all years was lower in individuals with RSV versus influenza (7.2/100,000 vs. 49.7/100,000 individuals). ICU admissions and median LOS were similar by age group for both viruses. Age-standardized mortality was 6.3/100,000 individuals and 6.1/100,000 individuals in patients with RSV and influenza, respectively, and mortality rates were similar in older adults (≥ 65 years) for both viruses.

CONCLUSIONS

RSV and influenza infection were associated with considerable HRU. There is a substantial disease burden for RSV infection in older adults ≥ 65 years. While RSV hospitalization rates in adults reported here appeared lower than influenza, RSV is still underdiagnosed in the hospital setting and its incidence might be similar to, or higher than, influenza.