bluuebunny/crossref_metadata_2025_split huggingface dataset:
P-680. Estimated Respiratory Syncytial Virus (RSV)-Related Hospitalizations and Deaths among Adults in Norway between 2010–2019
Authors: Casas Maribel , Molden Tor , Liang Caihua , Bruyndonckx Robin , Biyadgie Ewnetu Worku , Peerawaranun Pimnara , Molalign Moges Solomon , Polkowska-Kramek Aleksandra , Gessner Bradford D , Begier Elizabeth 
Published: January 2025

Abstract

Background
RSV can trigger acute cardiac events and cause respiratory disease in adults, but the true burden of RSV-associated disease and mortality remains largely underestimated due to limited standard-of-care testing and reduced test sensitivity. We retrospectively estimated the incidence of hospitalizations and deaths attributable to RSV in adults in Norway from 2010 to 2019

Methods
Counts of weekly hospitalizations and monthly deaths due to cardiorespiratory (ICD-10 codes: I00-I99, J00-J99), respiratory (J00-J99), and cardiovascular (I00-I99) diseases were obtained from the Norwegian Patient Registry and Norwegian Cause of Death Registry national databases, respectively. A quasi-Poisson regression model was fitted, stratified by age group, to estimate the number of hospitalizations and deaths attributable to RSV while considering temporal trends and virus activity. RSV and influenza hospitalizations in children aged &lt; 2 years and adults aged ≥65 years, respectively, were used as proxies for viral activity. Annual RSV-attributable hospitalization incidence and mortality rates were calculated using populations at risk as denominator.

Results
For all three study outcomes, RSV-attributable incidence and mortality rates increased with age. The highest RSV-attributable rates were observed in patients aged ≥65 years (range from 2010 to 2019 - hospitalizations per 100,000 person-years: 148-265 for cardiorespiratory, 81-143 for respiratory, and 124-221 for cardiovascular; deaths per 100,000 person-years: 19-35 for cardiorespiratory, 11-19 for respiratory, and 10-18 for cardiovascular). In any given year, the RSV-attributable cardiorespiratory disease hospitalization incidence and mortality rates were two times higher than the rates for respiratory disease alone. For the three outcomes, the attributable proportion of RSV hospitalizations was 2 to 3 times higher in adults aged 18-44 years than in those aged ≥65 years.

Conclusion
In Norway, RSV contributes substantially to both respiratory and cardiovascular diseases across all adult age groups, emphasizing the need for effective preventive strategies. Including cardiovascular disease increased measured burden by nearly 2-fold compared to respiratory disease alone.

Disclosures
Maribel Casas, PhD, Pfizer: Advisor/Consultant Tor Molden, PhD, Pfizer: I am an employee of Pfizer Caihua Liang, MD, PhD, Pfizer: Stocks/Bonds (Private Company) Aleksandra Polkowska-Kramek, n/a, Pfizer: employee of P95 which received funding from Pfizer to conduct this study Bradford D. Gessner, M.D., M.P.H., Pfizer: Employee|Pfizer: Stocks/Bonds (Public Company) Elizabeth Begier, MD, M.P.H., Pfizer Vaccines: Employee|Pfizer Vaccines: Stocks/Bonds (Private Company)
P-689. Respiratory Syncytial Virus Infection in Patients with Cancer at Referral Oncologic Center in Mexico City
Authors: Salto-Quintana Jack N , Cardona Ortiz Alex , Martinez-Rivera Nancy , Becerril-Vargas Eduardo , Martin-Onräet Alexandra , Vilar-Compte Diana 
Published: January 2025

Abstract

Background
Respiratory Syncytial Virus (RSV) infection has a high risk of complications in patients with cancer. This study aimed to describe the clinical characteristics and outcomes of oncologic patients infected with RSV in a tertiary care hospital.

Methods
A retrospective study was conducted over ten years at the National Cancer Institute in Mexico City. Adults with a confirmed diagnosis of cancer and RSV by polymerase chain reaction (PCR) were included.

Results
Fifty-seven cases of RSV infection were included, 29 (50.9%) were women, the median age was 48 years (IQR 34-12), 15 (26.3%) were &gt; 60 years; 36 (61%) had hematologic malignancies, and 23 (38.9%) solid tumors (two patients had both); 31 (54.4%) patients had active cancer; 24 (42.1%) received chemotherapy in the preceding 30 days. The most frequent comorbidities were hypertension (28.1%), obesity (17.5%), and diabetes (14%). Twenty-four (42.1%) patients had &gt; 5 points on the Charlson comorbidity index. Fifty-seven percent of patients presented Systemic Inflammatory Response Syndrome.
Fifty-four percent were diagnosed during winter (December to February) (n=22). According to the immunodeficiency index for progression risk prediction in hematological patients with RSV disease, 13 (36.1%) patients were at high risk.
Seventy percent were hospitalized, although only 52.6% for pneumonia. Respiratory progression or deterioration was documented in 11 (19.3%) patients; 5 (8.8%) required mechanical ventilation, and 4 (7%) were admitted to the ICU.
Eleven (19.3%) patients were treated with ribavirin, with no outcome differences (P= NS). Co-infection was documented in 15 patients (26.3%): 4 (7%) had bacteremia, 2 (3.5%) had bacterial pneumonia, and 5 (8.7%) had other bacterial infections. Seven (12.2%) patients had viral co-infection: 4 (7%) with COVID-19, 2 (3.5%) with rhinovirus and one (1.7%) with influenza. The 30-day mortality was 14.8% (n=8/54).

Conclusion
In this cohort, morbidity and mortality were high. The therapeutic options for RSV infection are limited. Currently, there are effective preventive measures for some risk groups; however, they do not include oncologic patients. These data provide relevant information about the burden of disease in adults with cancer.

Disclosures
All Authors: No reported disclosures
P-693. RSV Pneumonia Incidence in Solid Organ Transplant Recipients from 2014 to 2023 in an US Collaborative Network
Authors: Contreras German , Golovko Georgy 
Published: January 2025

Abstract

Background
Few studies have assessed the burden of RSV disease in solid organ transplant recipients (SOTr). The aim of our study is to determine the cumulative incidence (CI) and outcomes of RSV pneumonia among SOTr over 10 years.
Cumulative Incidence of RSV Pneumonia in SOTr 2014-2023

Methods
We used the TriNetX platform to access aggregated and de-identified EHRs from healthcare organizations in the USA from January 1st of 2014 to December 31st of 2023. We included individuals ≥18 years old with history of Heart, Lung, Kidney, or Liver transplantation. RSV infection status was based on RSV laboratory testing and clinical diagnosis codes (CPT and ICD-10, respectively). The index event was defined as the day of the first positive RSV test. The primary outcomes of interest were ICU admission, Invasive Mechanical ventilation, and all-cause mortality 30-days after index event. We used the TriNetX built-in functions to perform analysis.

Results
A total of 34,301 SOTr recipients were tested for RSV and 1671 were positive for RSV infection.
The population was mainly Male (53%) and No Hispanic (87%) with a median age at the time of diagnosis of 56 years. A high proportion of the cases were diagnosed in the South (37%) and Midwest (24%).
The CI of RSV Pneumonia significantly increased from 2014 to 2023, and it was higher among Hispanic, individuals ≥ 64 years old and among heart transplant recipients (Figure A-B).
During the observation period 137 (8.2%) were admitted to ICU, 99 (5.9%) required mechanical ventilation and 455 (27.2%) had complications with the transplanted organ during the RSV episode and 42 (2.5%) died.

Conclusion
We found evidence of substantial ethnic and age inequalities in the incidence of RSV pneumonia in SOTr recipients.

Disclosures
All Authors: No reported disclosures
P-695. Analysis of Seasonal Influenza Activity in Los Angeles County throughout the COVID-19 Pandemic
Authors: Ransohoff Heidi , Traub Elizabeth , Maurice Annabelle de St 
Published: January 2025

Abstract

Background
COVID-19 pandemic restrictions impacted flu transmission, leading to lower incidence and high influenza activity outside of the typical respiratory season. Los Angeles County (LAC) Department of Public Health (DPH) typically defines flu season in LAC as the first week of October through the end of March. Because positive flu results became reportable in LAC via electronic laboratory reporting (ELR) in October 2019, this analysis uses this new data source to describe flu positive tests from the current and previous four flu seasons to understand how flu activity in LAC changed throughout the pandemic.

Methods
This analysis includes influenza positive test results for LAC residents reported to DPH via ELR with specimen collection dates from October 2019 to March 2024. Results were deduplicated at the specimen level. Descriptive statistics were used to analyze positive tests.

Results
During the 2023-24 flu season from October 2023 through March 2024, 39,412 positive influenza results were reported (87% flu A; 13% flu B), with the greatest number of positive results for flu A observed in December 2023 and flu B observed in February 2024. During the same months of previous seasons, the number of positive tests ranged from 217 tests in the 2020-21 season to 40,843 tests in the 2022-23 season. Peak months of flu activity ranged from November in the 2022-23 season to May in the 2021-22 season.
For all tests reported during the study period, subtyping was reported for 8% of positive flu A specimens. Lineage typing was reported for 0.04% of positive flu B specimens. During the current flu season, at least 1 positive test has been reported for flu A/H1, flu A/H3, and flu B/Victoria. The last recent positive flu B/Yamagata specimen was reported in January 2020.

Conclusion
Results show that flu activity in LAC during the current flu season appears to be returning to pre-COVID-19 pandemic seasonality; flu B activity peaked later in the season, which has been described for previous flu seasons. During the pandemic, peak months of flu activity varied from what is usually observed. No positive flu B/Yamagata tests since 2020 may support ongoing efforts to assess flu B/Yamagata extinction during the COVID-19 pandemic, prompting the World Health Organization to recommend excluding flu B/Yamagata from flu vaccines.

Disclosures
All Authors: No reported disclosures
P-699. The Impact of Low Influenza Immunization rates on U.S. Hospital System Resources. A Dynamic Model estimation
Authors: Nguyen Van , Mould-Quevedo Joaquin F 
Published: January 2025

Abstract

Background
Increasing influenza vaccination rates can significantly reduce the onset of severe symptoms and reduce the risk of complications. This helps alleviate the burden during flu seasons when hospitals may be overwhelmed with patients. Nevertheless, the overall vaccine uptake has been decreasing in the United States which is expected to have an important effect by increasing the burden of disease. The aim of this study was to estimate the impact of low influenza vaccination rates on disease burden and U.S. hospital system resources.

Methods
The impact of the reduced flu immunization rate was estimated using a dynamic age-stratified transmission model. Two U.S. flu seasons (2011-2012 for low incidence and 2017-2018 for high incidence) were used in the analysis to simulate the variation of flu epidemic. This study assessed four different flu vaccination rates: 25%, 30%, 35% and 40%. Outcome measures include number of infections, outpatient visits, hospitalizations, intense care unit (ICU) stays and deaths. The flu vaccine effectiveness (VE) rate was taken from CDC reports to estimate an average VE for all ages for the last 10 seasons (42%). Vaccination rates by age group were estimated using CDC reports and this model assumed immunization with quadrivalent flu vaccines for all ages. Total number of acute hospital and ICU hospital beds available for influenza were assumed in the U.S. at 300,000 and 30,000, respectively.

Results
Using U.S. flu immunization rate from season 2023-2024 (≈35%), in case of a high flu incidence season, the total number of symptomatic infections is expected to result in 71M, office visits in 29M, hospitalizations in 0.94M and deaths in 133,670. Any scenarios with an immunization rate below 45% will generate significant pressure on the US hospital system and would saturate the number of ICU hospital beds in high incidence seasons. Only increasing the flu immunization rate up to 50% or higher may prevent any saturation of acute hospital or ICU hospital beds regardless on the incidence of the flu season.

Conclusion
The U.S. analyses shows the critical need to increase the U.S. flu immunization rates to at least 50%, to improve health outcomes and avoid saturation of hospital system resources, especially those associated to ICU hospital beds.

Disclosures
Van Nguyen, PhD, CSL Seqirus USA: Advisor/Consultant Joaquin F. Mould-Quevedo, PhD, CSL Seqirus USA: Stocks/Bonds (Private Company)
P-710. Epidemiology of RSV infections in a birth cohort of healthy children, PREVAIL Cohort 2017-2020
Authors: Leon Maria Deza , Conrey Shannon C , Epperson Monica , Coughlin Melissa , Cline Allison R , Mattison Claire , Payne Daniel C , McMorrow Meredith L , Morrow Ardythe L , Thornburg Natalie J , Staat Mary A 
Published: January 2025

Abstract

Background
Acute bronchiolitis due to respiratory syncytial virus (RSV) is the leading cause of hospitalizations in infants in the United States. Most available data on RSV epidemiology were obtained from hospital cohorts or medically attended illnesses, focusing on symptomatic children. We examined the PREVAIL Cohort (2017–2020) of healthy, term infants in Cincinnati, Ohio to understand the epidemiology of RSV infections in a birth cohort under weekly surveillance.
Table 1
Medical attendance by age group, PREVAIL Cohort, Cincinnati, Ohio, 2017–2020

Methods
Children who were at least 70% adherent to the weekly sample protocol were included in this analysis. Weekly, mid-turbinate nasal swabs were tested using the Luminex Respiratory Pathogen Panel PCR test. Child serum samples were collected at birth, 6 weeks, and 6, 12, 18, and 24 months of age. Symptoms status and medical visits were obtained weekly via SMS text messaging. RSV detection was defined as a swab positive for RSV (A or B) or an increase in RSV pre-fusion log10 IgG ( &gt;0.32) or IgA ( &gt;0.20) F-antibody levels. Medical charts were reviewed for unreported medical visits. Asymptomatic infection was defined as no reported fever or cough onset within 7 days of the first PCR positive result.
Figure 1
Cumulative incidence of RSV detections by nasal swab and serology, PREVAIL Cohort, Cincinnati, Ohio, 2017–2020

Results
Overall, 137 infections were identified in 74/101 (73%) children: 66% (n=91) of infections were identified by PCR (48 (35%) RSV A, 43 (31%) RSV B) and 34% (n=46) were identified only by serology (subtype unknown). Two-year cumulative incidence was 65% by PCR only and increased to 73% when including serology; annual incidence was 0.71 infections/child year. Reinfections were common, with 48 (35%) second and 15 (11%) third infections by 2 years of age. Of the 91 PCR-identified infections, 24 (26%) were asymptomatic, 22 (24%) were symptomatic but not medically attended, and 45 (50%) were medically attended, of which 8 (18%) were hospitalized or seen in the emergency department. Seasonality of infection peaked between November and January, although infections were identified in the spring and summer months.
Seasonality of RSV infections throughout the study period (2017-2020) grouped by RSV subtype, PREVAIL Cohort, Cincinnati, Ohio

Conclusion
RSV infections were common in the PREVAIL cohort; most infections were symptomatic, but few were severe. Calculating RSV incidence using only medically attended cases of RSV underestimates disease burden and overestimates the proportion of severe cases.

Disclosures
Mary A. Staat, MD, MPH, Cepheid: Grant/Research Support|Merck: Grant/Research Support|Pfizer: Grant/Research Support|Up-To-Date: Honoraria
P-712. Effectiveness of Seasonal Influenza Vaccines against Medically Attended Influenza B, US Flu VE Network
Authors: Price Ashley , Chung Jessie R , Ellington Sascha , Flannery Brendan 
Published: January 2025

Abstract

Background
Quadrivalent influenza vaccines including both B/Victoria and B/Yamagata components were introduced during the 2013-2014 season in the United States. With the worldwide interruption of influenza B/Yamagata virus circulation since March of 2020, trivalent vaccines including a B/Victoria component are expected to be recommended for the 2024-2025 season. We describe quadrivalent vaccine effectiveness (VE) against medically attended influenza B from 2016-2017 through 2019-2020 when the majority of the seasonal influenza vaccinations were quadrivalent.

Methods
Study sites enrolled patients aged ≥6 months with acute respiratory illness and tested for influenza by RT-PCR. VE against influenza B was estimated using a test-negative design as 100% x (1 – adjusted odds ratio) comparing receipt of vaccination among B cases versus influenza-negative patients using logistic regression models adjusting for age, race/ethnicity, sex, calendar time and study site.

Results
Over 4 seasons, 34,994 patients were enrolled, including 2,849 influenza B cases (1,507 [53%] type B/Yamagata and 1,342 [47%] B/Victoria), 7,539 influenza A cases (3,048 [40%] H1N1 and 4,491 [60%] H3N2) and 24,607 patients without influenza. Among influenza B cases, ratios of B/Yamagata to B/Victoria varied by season; no B/Yamagata cases were confirmed after 2020. By season, quadrivalent vaccine effectiveness among patients of all ages ranged from 48% to 55% against B/Yamagata and 56% to 85% against B/Victoria. VE tended to be highest among children aged 6 months – 8-years and against B/Victoria associated illness.

Conclusion
Quadrivalent vaccines were effective against both lineages of influenza B viruses. Monitoring effectiveness of trivalent vaccines against B/Victoria and continued surveillance for emerging B lineages will be important.

Disclosures
All Authors: No reported disclosures
P-721. Risk Factors Associated with COVID-19 Among Fully Vaccinated Healthcare Workers in Lima, Peru
Authors: romero Candice , Ponce Diana , Soto Giselle , Marcenac Perrine , Leidman Eva , Mahon Garrett W , Fowlkes Ashley , Nayra Joan M 
Published: January 2025

Abstract

Background
Healthcare workers (HCWs) are an important target group for COVID-19 vaccination. In February 2021, Peru launched a COVID-19 vaccination campaign among HCWs using a BBIBP-CorV inactivated whole-virus vaccine (Sinopharm). We aim to understand risk factors for SARS-CoV-2 infection after vaccination using a cohort of HCWs in two hospitals in Lima, Peru.

Methods
Between August 2021-June 2022, HCW who received at least two COVID-19 Sinopharm vaccine doses were enrolled in the cohort and followed for 6 months. Participants provided a self-collected nasal swab weekly for SARS-CoV-2 by reverse transcriptase polymerase chain reaction testing. SARS-CoV-2 infection was confirmed by a positive PCR test result at least 14 days after receiving the second vaccine dose. Adjusted hazard ratios (aHR) were used to identify associations with infection accounting for potential confounding. Person-time was calculated based on days between negative PCR results, capped at 10 days; in cases of infection, the time between positive and negative tests was halved, with half the days considered at risk.

Results
Of 670 vaccinated HCWs, 111 (16.6%) tested positive for SARS-CoV-2 during the follow-up period. In adjusted models, prior report of COVID-19 illness in the previous 12-months was associated with reduced risk of infection (aHR: 0.98 [95% CI:0.97‒0.99], p=0.026). Being beyond 6 months since the last vaccination was significantly associated with an increased risk of infection (aHR: 3.22 [95% CI:1.66‒6.23], p=0.0001) as well as working in an outpatient setting (aHR: 1.94 [95% CI:1.06‒3.53], p=0.031).

Conclusion
In this cohort of healthcare workers undergoing regular asymptomatic COVID testing, our findings suggest evidence of waning protection at 6 months post-vaccination BBIBP- CorV. Additionally, preliminary indications suggest that healthcare worker behaviors or specific occupational exposures may contribute to increased infection risk even following vaccination. In addition, these results support the inclusion of HCWs as a priority group for additional booster doses of COVID-19 vaccine at 6 months after the most recent dose.

Disclosures
All Authors: No reported disclosures
P-750. The Use of Doxycycline for MRSA SSTIs in the Setting of Tetracycline Resistance (The DOXY-MASTER Study)
Authors: Nham Ashly , sikand harminder , Sullivan Eva 
Published: January 2025

Abstract

Background
Inducible doxycycline resistance has been reported in tetracycline (TET)-resistant methicillin-resistant Staphylococcus aureus (MRSA) isolates. The two major resistance mechanisms found in MRSA involve efflux pump expression and ribosomal protection proteins (RPP), both of which are mediated by the presence of tet genes. In isolates that are positive for tetK and negative for tetM, in vitro studies have demonstrated an increase in the mean minimum inhibitory concentration (MIC) of doxycycline above the Clinical and Laboratory Standards Institute (CLSI) breakpoint for susceptibility after incubation in broth containing doxycycline. This study aims to investigate the presence of inducible resistance as defined by treatment failure with the use of doxycycline for MRSA skin and soft tissue infections (SSTIs) in the setting of tetracycline resistance.

Methods
This retrospective study analyzed patients from a 5-hospital health system and ensuing outpatient clinics from January 1, 2022 to February 29, 2024. Eligible patients were adults that had received doxycycline for the treatment of SSTI with a positive skin and soft tissue culture for MRSA that was susceptible to doxycycline. Exclusion criteria included presence of other organisms or concomitant infections requiring antimicrobial therapy, receipt of &gt; 24 hours of effective systemic antimicrobial therapy against MRSA, and suspected or confirmed osteomyelitis or septic arthritis.

Results
A total of 164 patients were screened, and 35 patients met the inclusion criteria for analysis: 11 in the TET-resistant arm and 24 in the TET-susceptible arm. Any readmission occurred in 6 (54.5%) patients in the TET-resistant arm and 7 (29.2%) patients in the TET-susceptible arm. However, readmission for SSTIs occurred in 1 patient (9.1%) in the TET-resistant arm and 2 patients (8.3%) in the TET-susceptible arm (p &gt;0.999) with an average of 39.3 and 20.3 days to readmission (p = 0.179), respectively.

Conclusion
In this small study sample, the use of doxycycline for MRSA SSTIs in the setting of tetracycline-resistance had no difference in treatment failure when compared to its use in tetracycline-susceptible isolates. This data suggests that susceptibility to doxycycline may be preserved in tetracycline-resistant MRSA isolates.

Disclosures
All Authors: No reported disclosures