1046. Assessing School-Based COVID-19 Transmission in Middle and High Schools in an Underserved Population through Qualitative Interviews

Background

Case and contact investigation is a mitigation strategy to understand transmission of diseases. The goal of this study is to assess COVID-19 transmission in schools that employ contact tracing.

Methods

Five middle and high schools provided a list of ongoing student and staff cases and their school contacts for the 2021-22 school year. Cases were eligible for interview if they had a known positive test or were a “presumed positive” by a practitioner. Contacts were eligible if they were identified as a close contact to a case within their school. Contacts who later became a case were eligible for a separate case interview. Trained interviewers contacted eligible individuals to offer COVID-19 resources and determine interests in participating in the study. Interested cases and contacts underwent a semi-structured interview with standardized questions.

Results

From 5/2021-4/2022, 360 cases (45% during Omicron surge) and their 412 contacts were identified (Fig 1). Among the 111 cases interviewed, 75% were students, half were in grades 6-8 (Fig 2). 61% of the cases were vaccinated with their primary series. 92% were symptomatic and fatigue, cough, and headaches were the most common symptoms. Transmission from school occurred in 29% (Fig 3) and most commonly occurred in the classroom. Among the 68 contacts interviewed, 96% were students. The two most reported activities contacts participated in were band (n=9) and sports (n=22), 10 from playing basketball. Three contacts reported exposure to COVID-19 within the household and five contacts reported exposure outside the home or school.

Conclusion

Case and contact investigation can be a valuable tool to assess COVID-19 transmission in schools. Almost one-third of cases reported school exposures, a greater school transmission rate than previous reported likely do to the increased transmissibility of Omicron. Assessing transmission events with this strategy alone may be limited by its reliance on self-reports. Case investigations can help schools identify potential areas to improve in limiting school-based COVID-19 transmission.

Disclosures

Sara Malone, PhD, LCSW, AHRQ: Grant/Research Support|NIH: Grant/Research Support Jason Newland, MD, AHRQ: Grant/Research Support|Merck: Grant/Research Support|NIH: Grant/Research Support|PEW Charitable Trust: Grant/Research Support|Pfizer: Grant/Research Support.

Assessing COVID-19 testing strategies in K-12 schools in underserved populations: study protocol for a cluster-randomized trial

Background

Since March 2020, COVID-19 has disproportionately impacted communities of color within the United States. As schools have shifted from virtual to in-person learning, continual guidance is necessary to understand appropriate interventions to prevent SARS-CoV-2 transmission. Weekly testing of students and staff for SARS-CoV-2 within K-12 school setting could provide an additional barrier to school-based transmission, especially within schools unable to implement additional mitigation strategies and/or are in areas of high transmission. This study seeks to understand the role that weekly SARS-CoV-2 testing could play in K-12 schools. In addition, through qualitative interviews and listening sessions, this research hopes to understand community concerns and barriers regarding COVID-19 testing, COVID-19 vaccine, and return to school during the COVID-19 pandemic.

Methods/design

Sixteen middle and high schools from five school districts have been randomized into one of the following categories: (1) Weekly screening + symptomatic testing or (2) Symptomatic testing only. The primary outcome for this study will be the average of the secondary attack rate of school-based transmission per case. School-based transmission will also be assessed through qualitative contact interviews with positive contacts identified by the school contact tracers. Lastly, new total numbers of weekly cases and contacts within a school-based quarantine will provide guidance on transmission rates. Qualitative focus groups and interviews have been conducted to provide additional understanding to the acceptance of the intervention and barriers faced by the community regarding SARS-CoV-2 testing and vaccination.

Discussion

This study will provide greater understanding of the benefit that weekly screening testing can provide in reducing SARS-CoV-2 transmission within K-12 schools. Close collaboration with community partners and school districts will be necessary for the success of this and similar studies.

Trial Registration

NCT04875520. Registered May 6, 2021.

POS0883 BIOPHYSICAL PROPERTIES OF MONOCYTES INDICATE DISEASE ACTIVITY, SEVERITY OF FIBROTIC OR MICROVASCULAR MANIFESTATIONS AND THE RISK FOR PROGRESSION IN SYSTEMIC SCLEROSIS

Background

Dysregulated immune responses are major pathogenic players in systemic sclerosis (SSc). The biophysical properties (such as cell deformation, Young’s modulus (a measure of cell stiffness) and area) of circulating immune cells reflect their states and functions, as well as their pathological activation (1-3). Thus, biophysical phenotyping can provide access to a novel, mostly unexplored layer of information that is currently not accessible with standard techniques of cellular and molecular biology. Real-time fluorescence and deformability cytometry (RT-FDC) is a novel technique that enables biophysical phenotyping of individual immune cells at a high throughput, which allows its use in a clinical setting (3-5).

Objectives

Here, we hypothesized that biophysical properties of circulating immune cells in SSc and rheumatoid arthritis (RA) might specifically reflect their distinct pathophysiological activation in the respective disease, and might indicate clinical outcomes such as disease activity or severity. We thus performed RT-FDC-based biophysical phenotyping of circulating immune cells in SSc, RA and healthy controls.

Methods

63 SSc patients, 59 RA patients fulfilling the respective ACR/EULAR classification criteria and 18 age- and sex-matched healthy controls were included in the study between 05.2019 and 09.2021. Peripheral blood mononuclear cells (PBMC) were isolated and immunolabelled. PBMC subpopulations were identified in RT-FDC by standard gating strategies based on their marker expression and their deformation, Young’s modulus and area were determined.

Results

We identified SSc-specific changes (changes in SSc, but not in RA compared to healthy controls) in the biophysical properties of NK, NKT-like cells and monocyte subpopulations in SSc. Monocytes subpopulations had a higher deformation and cross-sectional area and/or more compact intra-donor distributions of these parameters in patients with active disease and with extensive skin or lung fibrosis in comparison with patients with stable disease and limited skin or lung fibrosis, respectively. All monocytes subsets were stiffer in patients with progression of skin of lung fibrosis at the time of measurement in comparison with a previous visit. The deformation and area of intermediate monocytes could also identify patients at risk for future progression of lung fibrosis. Changes in biophysical properties of monocytes can indicate, beyond fibrotic burden, clinical manifestations of microvascular damage such as active digital ulcers and pulmonary arterial hypertension.

Conclusion

We demonstrated that changes in the biophysical properties of monocytes subsets are associated with multiple clinical outcomes in SSc such as disease activity, severity of fibrotic or microvascular manifestations and risk of progression and might thus directly reflect SSc-specific pathologic immune cell activation. Our results thus provide first evidence that RT-FDC-based biophysical phenotyping of circulating immune cells may be a useful tool for clinical evaluation of SSc patients.

References

[1]Bashant KR, Toepfner N, Day CJ, Mehta NN, Kaplan MJ, Summers C, et al. The mechanics of myeloid cells. Biol Cell. 2020;112(4):103-12.

[2]Toepfner N, Herold C, Otto O, Rosendahl P, Jacobi A, Krater M, et al. Detection of human disease conditions by single-cell morpho-rheological phenotyping of blood. Elife. 2018;7.

[3]Kubankova M, Hohberger B, Hoffmanns J, Furst J, Herrmann M, Guck J, et al. Physical phenotype of blood cells is altered in COVID-19. Biophys J. 2021;120(14):2838-47.

[4]Otto O, Rosendahl P, Mietke A, Golfier S, Herold C, Klaue D, et al. Real-time deformability cytometry: on-the-fly cell mechanical phenotyping. Nat Methods. 2015;12(3):199-202, 4 p following

[5]Rosendahl P, Plak K, Jacobi A, Kraeter M, Toepfner N, Otto O, et al. Real-time fluorescence and deformability cytometry. Nat Methods. 2018;15(5):355-8.

Disclosure of Interests

Alexandru-Emil Matei: None declared, Kubánková Markéta: None declared, Liyan Xu: None declared, Andrea-Hermina Györfi: None declared, Evgenia Boxberger: None declared, Despina Soteriou: None declared, Maria Papava: None declared, Julia Prater: None declared, Xuezhi Hong: None declared, Martin Kräter: None declared, Georg Schett: None declared, Jochen Guck: None declared, Jörg H.W. Distler Shareholder of: JHWD is stock owner of 4D Science., Consultant of: JHWD has consultancy relationships with Actelion, Active Biotech, Anamar, Bayer Pharma, Boehringer Ingelheim, Celgene, Galapagos, GSK, Inventiva, JB Therapeutics, Medac, Pfizer, RuiYi and UCB, Grant/research support from: JHWD has received research funding from Anamar, Active Biotech, Array Biopharma, aTyr, BMS, Bayer Pharma, Boehringer Ingelheim, Celgene, Galapagos, GSK, Inventiva, Novartis, Sanofi-Aventis, RedX, UCB

New methodology for viability testing in environmental samples

Environmental samples can be complex and are comprised of microorganisms and a matrix of decaying organic matter as well as an inorganic phase such as sand or precipitated material (waste water, sludge, soils, etc.). Nucleic acid dyes have recently been developed to address the growing need for environmental analyses (cell staining, counting, viability testing and specific organism identification). However, certain dyes may not be ideally suited for testing of environmental samples, because they readily adhere to the substrate material as well as their target molecule, resulting in increased non-specific binding and background fluorescence. The aim of this study was to address the limitations of the widely used and commercially available Live/Dead BacLight Bacterial Viability kit (Molecular Probes, Eugene, OR). A new combination of nucleic acid dyes, i.e. SYTO13 and SYTOX Orange (Molecular Probes, Eugene, OR), was proposed as an alternative. The dyes were carefully chosen for their spectral separation and increase of fluorescence quantum yield. A protocol for this combination was first designed and optimized and the two staining assays were compared against suspensions of live and dead E. coli, mixed in different proportions and it was shown that both protocols performed equally on pure cultures. However, when testing activated sludge samples, the commercial kit showed greater background fluorescence and non-specific binding than the alternate combination. Therefore, the proposed dye combination and its corresponding protocol are deemed more suitable for use on complex environmental samples than the Live/Dead BacLight Bacterial Viability kit.