bluuebunny/crossref_metadata_2025_split huggingface dataset:
P-2340. Single-Center Inpatient Measles Analysis During a Congregate Setting Outbreak; Comparing Vaccine History between Measles Positive and Negative Cohorts
Authors: Fricchione Marielle J , Nguyen David , Nash Colleen B 
Published: January 2025

Abstract

Background
Chicago’s 2024 measles outbreak affected many new arrivals living in congregate settings with unknown or poorly documented vaccination history. Despite post-exposure prophylaxis provided at shelters, many families still developed measles. Frequency of measles exposure in congregate settings certainly plays a role in infection, but vaccination history and source should also be evaluated.Table.Characteristics of Measles Patients Under Investigation (PUI) stratified by PCR result
* One case received IGIM and five received 1 MMR post-exposure prophylaxis dose given at the shelter between 10—30 days prior to rash onset (median: 11 days), ∞ including vaccine strain case, # n=7, ^n=10, ^^Countries of origin: Venezuela, Peru, Ecuador

Methods
Data was abstracted from 12 measles PCR positive and 13 measles PCR negative patient charts from 3/10/24—4/23/24 including measles vaccination history, IgG antibody titers, concurrent infections and measles complications. Relative risks and p-values were calculated using MedCalc Software Ltd (Version 22.023).

Results
From 3/10/24—4/23/24, 12 measles PCR positive patients were admitted with median age 16 years (range 13 months—43 years) including 3 parent-child dyads; serotyping through the Illinois Department of Public Health reported one vaccine strain and 11 wild type cases. Of the 11 wild type measles cases, 3 (27%) had concurrent infections; (2 of 3 group A streptococcus culture positive (oropharynx); 1 of 3 was rhinovirus/enterovirus positive (nasopharyngeal PCR); 8 of 11 (73%) had at least 1 measles complication including dehydration (4), acute otitis media (3), pneumonia (1), and hepatitis (2). Comparing vaccine history between measles negative and positive cohorts, there was a non-significant trend towards history of international vaccination in the measles positive cohort. History of current congregate setting residence and exposure to a known measles case were significantly associated with measles positivity with a relative risk of 2.2.

Conclusion
Inpatient data is lacking during the 2024 international measles surge and new arrivals' vaccination history documentation is inconsistent. A trend towards international measles vaccine receipt in a measles positive cohort highlights the importance of US public health efforts to offer MMR vaccination to new arrivals. Limitations of this report include small cohort sizes and recall bias. Additional data is needed to describe the impact of improper vaccine storage and handling on vaccine effectiveness in the current international measles epidemic.

Disclosures
All Authors: No reported disclosures
P-2341. Was Viral Interference Responsible for the Unusual 2021-22 Influenza Season?
Authors: Krauland Mary G , Roberts Mark S 
Published: January 2025

Abstract

Background
Viral interference is a short-term, non-specific immunity that limits infection by a second virus when a person has been infected by a first virus. Epidemiological and biological data supports the existence of viral interference, most likely caused by interferon production in response to an infection. The 2021-22 influenza season in the US displayed a highly unusual pattern in which a single influenza variant displaying a bimodal pattern, with a fall rise in transmission followed by a winter decrease and subsequent increase. The addition of a refractory period to a simulation of co-circulation of an Omicron-variant COVID-19 like virus and an H3N2-like influenza virus produced similar transmission dynamics to that observed in the 2021-22 influenza season.Figure 1. Covid-19 Omicron variant and influenza cases in the US population and in the simulation.A: Reported Covid-19 Omicron variant and influenza cases in US in the 2021-22 season. B: Simulated COVID-19 and influenza cases with and without refractory period with varied prior immunity to COVID-19. Left Y-axis, influenza cases; right Y-axis, Covid-19 cases.

Methods
We used the Agent-based modeling platform FRED (Framework for Reproducing Epidemiological Dynamics), with inclusion of a model of Omicron-variant COVID-19 like virus and an H3N2-like influenza virus.

Results
In a simulation including a 7-day refractory period, the introduction of an Omicron-like variant in December of the season after influenza transmission was already widespread caused influenza transmission to subside while the Omicron-like variant was circulating at high rates. Influenza still circulated at lower levels and rebounded after the Omicron-like variant surge decreased since there was no cross-immunity between the 2 viruses and a large pool of influenza susceptible agents remained. The epidemic curve from this simulation resembled in shape the epidemic curve of H3N2 influenza in 2021-22 (Figure).
This effect was not present in similar simulations without a refractory period and was similar over the values of prior population immunity included in the simulation set.

Conclusion
Viral interference caused by widespread COVID-19 Omicron variant transmission is a plausible explanation for the unusual influenza infection pattern seen in the 2021-22 season. It is likely that viral interference is often influential in the interactions of a number of respiratory pathogens and should therefore be included in simulations that include multiple co-circulating respiratory pathogens.

Disclosures
All Authors: No reported disclosures
P-2344. Genomic Analysis of Monkeypox Virus (MPVX) Outbreak in Bangkok, Thailand in 2022-2023
Authors: Putcharoen Opass , Rattanatumhi Khwankamon , Supataragul Ananporn , Sangsub Pakamas , Wacharapluesadee Supaporn 
Published: January 2025

Abstract

Background
Since early May 2022, cases of mpox (monkeypox) have been reported in countries where the disease is not endemic, alongside continued reports from endemic regions. This marks the first time that multiple mpox cases and clusters have been concurrently reported in both non-endemic and endemic countries across diverse geographical areas. As of March 8, 2024, there were 94,776 confirmed mpox cases globally, with 721 cases in Thailand—most of which were reported from Bangkok.
Figure 1
The phylogenetic tree was constructed from 60 Mpox genomes collected in Bangkok, Thailand, during 2022-2023. The tree was produced using the maximum likelihood method in IQ-TREE2 with 1000 replicates of ultrafast bootstrap and HKY+F+I nucleotide substitution model and visualized by ggtree library in R.

Methods
We collected biological samples, mostly lesion swabs from suspected Mpox cases at STI Clinics in Bangkok, Thailand, from July 2022 to September 2023. Whole Genome Sequencing (WGS) was performed on 60 specimens from mpox cases in Bangkok, primarily lesion swabs, that were PCR-positive for MPXV with a cycle threshold (Ct) value below 30. A hybridization probe-capture–based approach was utilized for sequencing, specifically Illumina RNA Prep with Enrichment kit with the Viral Surveillance Panel. Consensus genomes were generated using an in-house pipeline based on reference mapping (BWA v0.7.17) to the Mpox reference genome from Nigeria (GenBank accession no. NC_063383.

Results
Phylogenetic analysis from WGS revealed that the predominant MPXV clade in Bangkok is IIb, with most specimens belonging to lineage IIb-C (48/60), followed by IIb-A (9/60) and IIb-B (3/60) as shown in Figure 1. Lineage IIb-A was detected in samples from 2022, while IIb-B and IIb-C were prominent in 2023. We identified multiple clusters with similar genomes in lineage IIb-C from different individuals, with percent identity ranging from 99.970% to 99.999% (197,184 nucleotides), suggesting ongoing community transmission. There is no clear introduction of lineage IIb-C into Thailand, however, the phylogenetic tree indicates the transmission of locally transmitted lineage to other countries. We detected the unique activity of APOBEC mRNA editing in serial samples from immunocompromised hosts. No mutations associated with resistance to tecovirimat were identified.

Conclusion
Our study demonstrated the introduction of MPXV from multiple countries, confirming ongoing community transmission in Bangkok during 2022-2023. Continuing genomic surveillance is crucial for tracking the epidemiology and viral evolution.

Disclosures
All Authors: No reported disclosures
P-2348. Predictors of Dengue Outcome after Adoption of a Management Protocol
Authors: Sigdel Keshav Raj , Pradhan Rehan , Lamichhane Saugat , Ranjitkar Nora , Koirala Janak 
Published: January 2025

Abstract

Background
Dengue caused a large outbreak in Nepal with over 54,000 reported cases in 2022. Once considered a disease of tropics, dengue has expanded to subtropical and temperate regions of Nepal including Kathmandu valley. A standard protocol, which included screening criteria for admission and treatment based on severity, was adopted at our hospital which is located at the epicenter of 2022 outbreak.

Methods
We enrolled 261 patients admitted to Patan Academy of Health Sciences between August and October, 2022. We analyzed patients’ baseline clinical and laboratory characteristics as predictors of outcomes including duration of stay and mortality.

Results
The mean age of the patients was 40.9 (±19.1) years with female predominance (54.4%). Most patients were from Lalitpur district followed by Kathmandu, which are the main catchment areas of the hospital and epicenter of 2022 outbreak. Most common clinical presentations included fever (93.5%),followed by vomiting (65.5%), myalgia (52.1%), headache (45.6%), mucosal bleeding (18.4%), eye pain (16%), anorexia (13.8%), loose stools (13.8%), and rash (10%). The patient’s age correlated directly with both systolic and diastolic blood pressures (p=0.002 and 0.01, respectively), and inversely with platelet counts (p=0.002).
Duration of hospital stay (median 3, IQR 2 days) correlated with aspartate aminotransferase (median 141 U/L) and alanine aminotransferase (median 90.5 U/L) levels at presentation (p&lt; 0.001 and p=0.03, respectively). Hemorrhagic rash occurred in 10 patients and was associated with low platelets at day 1 of admission (p=0.01). There were no deaths.

Conclusion
Elevated aminotransferases as a marker of hepatocellular injury was the main predictor of longer duration of hospital admission. With adoption of a standard screening and treatment protocol, despite varied clinical presentations and complications, no fatalities occurred among the 261 adult patients in our hospital. This underscores the importance of early detection and proper management in effectively combating the disease and preventing mortality.

Disclosures
All Authors: No reported disclosures
P-2351. Assumptions and Realities: Unraveling Varicella Zoster Virus Immunity in Unvaccinated Populations
Authors: Jordão Sofia , Pena Eduarda , Gonçalves Maria João , Batista Clara , Oliveira Susana Ramos , Azeredo Constança , Araújo Sara , Reis Fábio , Soeiro Cristina , de Abreu Ricardo Correia 
Published: January 2025

Abstract

Background
In countries without universal vaccination for chickenpox in childhood, a very high seroprevalence for varicella zoster virus (VZV) IgG in adults is often assumed. Consequently, some suggest vaccinating at-risk adults against herpes zoster, even if they lack a documented history of chickenpox, under the assumption of immunity. However, this presumption may not accurately reflect today's epidemiological landscape. Neglecting the risk of primary infection post-childhood could lead to severe outcomes in vulnerable adults, pregnant patients, and increase the likelihood of exposure for caregivers, potentially resulting in secondary transmission.
Graphic 1. Sample distribution by gender and age group.

Methods
A retrospective study was conducted on VZV serology among individuals aged 11 and above, from February 2014 to March 2024, who were unvaccinated and lacked known chickenpox history, within a Portuguese hospital.
Graphic 2. Varicella Zoster Virus IgG seroprevalence by gender and age group.

Results
Analysis of 613 patients (68% women, median age 39 years), all with high VZV infection risk due to comorbidities or immunosuppression, revealed an 83.6% VZV IgG positivity rate, increasing with age. Among working age individuals aged 21-60,12% were seronegative for VZV and 19.2% of women of childbearing age 16-40 showed no immunity.

Conclusion
Although common, the presence of antibodies against VZV is not universal after childhood in unvaccinated populations. Vaccination for herpes zoster is not indicated for the prevention of primary infection, so assuming immunity may fail to prevent it in a population at risk. Prevention of chickenpox relies on specific vaccination, or the use of immunoglobulin when the former is contraindicated, which implies recognition of this susceptibility. Serology remains a useful tool, especially for at-risk individuals and caregivers, and should be considered in women of reproductive age and immunocompromised individuals.

Disclosures
All Authors: No reported disclosures
P-2352. Post-pandemic SARS-CoV-2 vaccination and infection status and risk of influenza-like illnesses and work absenteeism in healthcare workers – a prospective cohort study
Authors: Dörr Tamara K , Lacy Joanne , Ballouz Tala , Cusini Alexia , Grässli Fabian , Haile Sarah , Kocan Emina , Carsten Möller J , Puhan Milo Alan , Schlegel Matthias , Von Kietzell Matthias , Rütti Markus , Stocker Reto , Vuichard-Gysin Danielle , Kahlert Christian , Kuster Stefan , Kohler Philipp 
Published: January 2025

Abstract

Background
In the transition to SARS-CoV-2 endemicity, we prospectively assessed whether the number of SARS-CoV-2 vaccinations was associated with influenza-like illness (ILI) episodes or work absenteeism in a cohort of healthcare workers (HCW).

Methods
In October 2023, we updated information on SARS-CoV-2 vaccination and infection within a prospective multi-centre HCW cohort. Anthropometric data and information on personal health, patient contact, and household structure were collected. Between 11/2023 and 04/2024 (i.e. follow-up), where community activity of SARS-CoV-2 and influenza were high, HCW filled in weekly questionnaires on acute viral symptoms and number of days absent from work. The main predictor was SARS-CoV-2 vaccination status grouped into unvaccinated, 1-2, 3, or≥ 4 vaccine doses. Outcomes were the number of ILI episodes and days absent from work. ILI was defined as acute-onset (≤ 7 days) of fever/feverish feeling and one respiratory symptom (runny nose, loss of smell, cough, sore throat). Using a negative binomial model, we calculated adjusted incidence rate ratios (aIRR) and 95% confidence intervals (CI) for SARS-CoV-2 vaccination status and the outcomes, adjusting for important confounders.

Results
We included 1’783 HCW (median 47 years, range 17-70), 178 (9.9%) were unvaccinated, 368 (20.6%) had 1-2 vaccinations, 910 (51.0%) 3 vaccinations and 327 (18.3%) ≥4 vaccinations (Table 1). Overall, 764 (42.8%) experienced ≥ 1 ILI episode during follow-up, the mean number of days absent from work was 2. In multivariable analysis, number of SARS-CoV-2 vaccinations was positively associated with number of ILI episodes (aIRR per dose 1.15, 95% CI 1.13-1.16), as did the number of positive SARS-CoV-2 tests (aIRR 1.13, 95% CI 1.11-1.16). Seasonal influenza vaccination (aIRR 0.80, 95% CI 0.77-0.83) was associated with decreased risk (Table 2). SARS-CoV-2 vaccination was also associated with days absent from work (aIRR 1.08, 95% CI 1.06-1.10).

Conclusion
The number of vaccinations against SARS-CoV-2 is not associated with decreased ILI episodes and absenteeism in HCW during high community transmission level of SARS-CoV-2 and influenza. In contrast, smoking and male sex are associated with increased and influenza vaccination with decreased risk.

Disclosures
Tala Ballouz, MD PhD, Moderna: Grant/Research Support
P-2360. Wastewater-Based Surveillance of Hepatitis A Virus Across Communities in Alberta, Canada
Authors: Weyant Benson , Ueno Aito , Waddell Barbara Jean M , Lee Jangwoo , Xiang Kevin , Du Kristine , Bender Aidan , Visser Gail , McCalder Janine , Papparis Chloe , Chavarriaga Maria Bautista , Fonseca Kevin , Swain Mark , Coffin Carla , Lee Bonita , Pang Xiao-Li , Drews Steven J , O’Grady Christine , Hubert Casey R J , Parkins Michael 
Published: January 2025

Abstract

Background
Hepatitis A virus (HAV) incident infection in Canada is rarely diagnosed (i.e. incidence of 3.6-10 cases/100,000 persons) (PMID: 18159360). Infections generally relate to imported contaminated food-products, or travelers returning from endemic countries. Due to its fecal-oral spread, possible underdiagnosis, and often-cryptic presentation, HAV is an ideal candidate for wastewater (WW)-based surveillance, a tool increasingly utilized to monitor infectious diseases globally.Figure 1.Longitudinal monitoring of HAV RNA wastewater abundance across eight Alberta municipalities over a 4-month period.

Methods
24-hour composite WW was collected weekly from eight geographically disparate, and socioeconomically diverse municipal WW treatment plants in Alberta from August to December 2023. After short-term cold storage, WW was centrifuged, and RNA from the raw pellet was extracted using Qiagen’s RNeasy PowerFecal pro. HAV levels were quantified by RT-qPCR of the vp1 gene. 2021 Canadian census data was used to define population demographics for each participating site.

Results
HAV was detected in 18/117 (15.4%) WW samples and 5/8 (62.5%) municipalities over the 4-month period (Figure 1). RNA abundance in HAV positive WW samples was a median of 3.4 copies/mL (IQR 0.44 - 6.97). Larger population size (p=0.007), and greater density (p=0.001) were associated with increased likelihood of HAV WW detection, whereas social and economic demographics of populations within sewershed catchments did not associate with likelihood of HAV detection (Table 1).

Conclusion
HAV RNA is rarely detected in the wastewater of Alberta. Detection was more frequently observed in larger municipalities, which is consistent with non-endemic, imported disease. WW surveillance can potentially be adapted to monitor HAV in the context of outbreaks to reduce secondary transmission, and safeguard public health.

Disclosures
Mark Swain, MD MSc, Abbott: Advisor/Consultant|Advanz: Advisor/Consultant|Gilead, BMS, CymaBay, Intercept, Genfit, Pfizer, Novartis, Astra Zeneca, GSK, Celgene, Novo Nordisk, Axcella Health Inc., Merck, Galectin Therapeutics: Grant/Research Support|GSK: Advisor/Consultant|Ipsen: Advisor/Consultant|Novo Nordisk: Advisor/Consultant Carla Coffin, MD MSc, Altimmune: Grant/Research Support|Gilead: Grant/Research Support|GSK: Grant/Research Support|Janssen: Grant/Research Support Steven J. Drews, PhD FCCM D(ABMM), Abbott: Grant/Research Support|Danaher: Honoraria|Roche: Advisor/Consultant|Roche: Grant/Research Support
P-2362. Risk Factors for Persistent and Recurrent CMV DNAemia in a Real-World Cohort of SOT and HSCT Patients Receiving Maribavir
Authors: Morinishi Chelsea , Schaenman Joanna M , Beaird Omer E , Gaynor Pryce , Multani Ashrit , Pham Christine , Yanagimoto-Ogawa Lauren 
Published: January 2025

Abstract

Background
Refractory/resistant (R/R) CMV infection, defined by persistent symptoms or DNAemia after at least two weeks of antiviral therapy, is associated with high rates of rejection and mortality in transplant patients. Maribavir (MBV) is a newer agent with demonstrated efficacy in achieving DNAemia clearance without the bone marrow suppression associated with conventional first line therapy. However, there is less data on the risk factors for treatment failure with MBV. We sought to evaluate clinical outcomes of MBV in transplant patients in a real-world patient cohort.Table 1:Demographic Characteristics

Methods
A retrospective chart review was conducted of adult solid organ transplant (SOT) and hematopoietic stem cell transplant (HSCT) recipients who received MBV for R/R CMV infection at a high-volume transplant center from 2021-2023. The main treatment outcome was failure (defined as persistence of DNAemia requiring a switch in therapy).Table 2:Risk Factors for Maribavir Failure

Results
Nineteen patients received MBV for CMV DNAemia or tissue-invasive disease. Overall, 84% were SOT, 63% had high-risk CMV serostatus, and 90% had asymptomatic DNAemia. Twenty-six percent of patients experienced MBV failure. The median absolute lymphocyte count (ALC) was 852 µL at MBV switch in those with successful treatment compared with 262 µL in those with MBV failure, although this did not reach statistical significance. Peak viral load was also not significantly associated with MBV failure. Five patients later developed MBV resistance by commercial genotype sequencing.

Conclusion
Real world use of MBV demonstrated comparable rates of viral clearance with clinical trial data in SOT and HSCT patients. While not statistically significant, there was a trend towards MBV failure in patients with lower ALC. Future studies may be useful to determine if switching to MBV before onset of worsening lymphopenia related to first line therapy would impact the rate of treatment failure and MBV resistance. The lack of association between VL and virologic response also suggests that MBV may be safely used in patients regardless of viral load.

Disclosures
Joanna M. Schaenman, MD, PhD, FAST, Eurofins Viracor: Honoraria|F2G: Grant/Research Support|MedCure: Advisor/Consultant|Moderna: Clinical trial support to institution|OneLegacy: Advisor/Consultant