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Background: Universities returned to in-person learning in 2021 while SARS-CoV-2 spread remained high. At the time, it was not clear whether in-person learning would be a source of disease spread., Methods: We combined surveillance testing, universal contact tracing, and viral genome sequencing to quantify introductions and identify likely on-campus spread., Results: Ninety-one percent of viral genotypes occurred once, indicating no follow-on transmission. Less than 5% of introductions resulted in >3 cases, with 2 notable exceptions of 40 and 47 cases. Both partially overlapped with outbreaks defined by contact tracing. In both cases, viral genomics eliminated over half the epidemiologically linked cases but added an equivalent or greater number of individuals to the transmission cluster., Conclusions: Public health interventions prevented within-university transmission for most SARS-CoV-2 introductions, with only 2 major outbreaks being identified January to May 2021. The genetically linked cases overlap with outbreaks identified by contact tracing; however, they persisted in the university population for fewer days and rounds of transmission than estimated via contact tracing. This underscores the effectiveness of test-trace-isolate strategies in controlling undetected spread of emerging respiratory infectious diseases. These approaches limit follow-on transmission in both outside-in and internal transmission conditions., Competing Interests: Potential conflicts of interest . D. H. H. reports consulting on COVID-19 prevention strategies for Xenophon Strategies, Inc., Major League Soccer, Professional Golf Association, and Equinox. No reported conflicts for other authors. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: The filovirus Bundibugyo virus (BDBV) causes severe disease with a mortality rate of approximately 20%-51%. The only licensed filovirus vaccine in the United States, Ervebo, consists of a recombinant vesicular stomatitis virus (rVSV) vector that expresses Ebola virus (EBOV) glycoprotein (GP). Ervebo was shown to rapidly protect against fatal Ebola disease in clinical trials; however, the vaccine is only indicated against EBOV. Recent outbreaks of other filoviruses underscore the need for additional vaccine candidates, particularly for BDBV infections., Methods: To examine whether the rVSV vaccine candidate rVSVΔG/BDBV-GP could provide therapeutic protection against BDBV, we inoculated seven cynomolgus macaques with 1000 plaque-forming units of BDBV, administering rVSVΔG/BDBV-GP vaccine to 6 of them 20-23 minutes after infection., Results: Five of the treated animals survived infection (83%) compared to an expected natural survival rate of 21% in this macaque model. All treated animals showed an early circulating immune response, while the untreated animal did not. Surviving animals showed evidence of both GP-specific IgM and IgG production, while animals that succumbed did not produce significant IgG., Conclusions: This small, proof-of-concept study demonstrated early treatment with rVSVΔG/BDBV-GP provides a survival benefit in this nonhuman primate model of BDBV infection, perhaps through earlier initiation of adaptive immunity., Competing Interests: Conflict of Interest . T. W. G. claims intellectual property regarding recombinant VSV-based vaccines for the prevention and treatment of filovirus infections. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: The Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is highly transmissible in vaccinated and unvaccinated populations. The dynamics that govern its establishment and propensity toward fixation (reaching 100% frequency in the SARS-CoV-2 population) in communities remain unknown. Here, we describe the dynamics of Omicron at 3 institutions of higher education (IHEs) in the greater Boston area., Methods: We use diagnostic and variant-specifying molecular assays and epidemiological analytical approaches to describe the rapid dominance of Omicron following its introduction into 3 IHEs with asymptomatic surveillance programs., Results: We show that the establishment of Omicron at IHEs precedes that of the state and region and that the time to fixation is shorter at IHEs (9.5-12.5 days) than in the state (14.8 days) or region. We show that the trajectory of Omicron fixation among university employees resembles that of students, with a 2- to 3-day delay. Finally, we compare cycle threshold values in Omicron vs Delta variant cases on college campuses and identify lower viral loads among college affiliates who harbor Omicron infections., Conclusions: We document the rapid takeover of the Omicron variant at IHEs, reaching near-fixation within the span of 9.5-12.5 days despite lower viral loads, on average, than the previously dominant Delta variant. These findings highlight the transmissibility of Omicron, its propensity to rapidly dominate small populations, and the ability of robust asymptomatic surveillance programs to offer early insights into the dynamics of pathogen arrival and spread., Competing Interests: Potential conflicts of interest. M. S. is cofounder of, shareholder in, and advisor to Rhinostics, Inc and reports a patent for an anterior nares swab (US provisional patent application 63/085,571). M. G., D. T., S. R., and E. W. are employed by Integrated DNA Technologies. D. T. reports stock or stock options from Danaher Corporation (payments to author). S. R. reports stock or stock options from Danaher Corporation. C. M. K. is cofounder of Biosens8, Inc and reports grants or contracts unrelated to this work from the NIH National Institute of General Medical Sciences, Defense Advanced Research Projects Agency, Uniformed Services University, and BU; reports consulting fees paid to author from Adventus Research + Consulting, Inc; is a member of the Biomedical Engineering Society Board; and has a leadership or fiduciary role with the American Institute for Medical and Biological Engineering. J. H. C. is a paid consultant for Cell Signaling Technologies and reports funding unrelated to this work from Mass CPR/Evergrande. W. P. H. serves on scientific advisory boards for Biobot Analytics, Inc and Merck; received consulting fees from Biobot Analytics; contributed expert witness testimony on the expected course of the pandemic for Analysis Group; and reports stock or stock options from Biobot Analytics. P. C. S. is a founder of and shareholder in Sherlock Biosciences, reports consulting fees from Sherlock Biosciences, reports patents for CRISPR technology (PCT/US2018/022764 and PCT/US2019/061577), and is on the board and serves as shareholder for the Danaher Corporation. B. A. P. reports lecture honoraria from the Harvard Secondary School Program and a patent for CRISPR technology (WO 2022/051667). D. H. H. reports funding from an institution unrelated to this work (CDC 1 U01CK000632-01-00 GeoSentinel); consultancy payments to the author from Major League Soccer, the Professional Golf Association of America, Equinox, and Xenophon Strategies, Inc; and participation as chair of a data and safety monitoring board for COVEDZ. M. T. G. reports stock or stock options from Danaher Corporation. T. B. reports grants or contracts unrelated to this work from Gilead Sciences, Inc and Fujifilm Pharmaceuticals U.S.A., Inc. M. H. reports consulting fees as an independent laboratory consultant for Nichols Management Group, LLC. All remaining authors: No reported conflicts of interest. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Infectious Diseases Society of America.)

Background: In January 2022, US guidelines shifted to recommend isolation for 5 days from symptom onset, followed by 5 days of mask-wearing. However, viral dynamics and variant and vaccination impact on culture conversion are largely unknown., Methods: We conducted a longitudinal study on a university campus, collecting daily anterior nasal swabs for at least 10 days for reverse-transcription polymerase chain reaction (RT-PCR) testing and culture, with antigen rapid diagnostic testing (RDT) on a subset. We compared culture positivity beyond day 5, time to culture conversion, and cycle threshold trend when calculated from diagnostic test, from symptom onset, by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant, and by vaccination status. We evaluated sensitivity and specificity of RDT on days 4-6 compared with culture., Results: Among 92 SARS-CoV-2 RT-PCR-positive participants, all completed the initial vaccine series; 17 (18.5%) were infected with Delta and 75 (81.5%) with Omicron. Seventeen percent of participants had positive cultures beyond day 5 from symptom onset, with the latest on day 12. There was no difference in time to culture conversion by variant or vaccination status. For 14 substudy participants, sensitivity and specificity of day 4-6 RDT were 100% and 86%, respectively., Conclusions: The majority of our Delta- and Omicron-infected cohort culture-converted by day 6, with no further impact of booster vaccination on sterilization or cycle threshold decay. We found that rapid antigen testing may provide reassurance of lack of infectiousness, though guidance to mask for days 6-10 is supported by our finding that 17% of participants remained culture-positive after isolation., Competing Interests: Potential conflicts of interest. D. H. H. reports funding from the Centers for Disease Control and Prevention for GeoSentinel (1 U01CK000632-01-00) paid to institution and unrelated to this study; personal consulting fees from Major League Soccer, Equinox, Xenophon Strategies, PGA of America; legal consulting fees from Hamilton, Miller & Birthisel, LLP; an unpaid role as data and safety monitoring board chair for a randomized trial to determine the effect of vitamin D and zinc supplementation for improving treatment outcomes among coronavirus disease 2019 patients in India (COVEDZ); and an unpaid volunteer position as secretary–treasurer for the GeoSentinel Foundation, Inc. C. M. K. reports grants or contracts unrelated to this work from NIH NIGMS, Uniformed Services University, BU, and DARPA; consulting fees paid to author from Adventus Research + Consulting, Inc; a leadership or fiduciary role on the Biomedical Engineering Society Board (member) and the American Institute for Medical and Biological Engineering; and 3.0% ownership and cofounder of BioSens8, LLC. J. H. C. reports funding (supports SARS-CoV-2 variant) from Mass CPR/Evergrande and consulting fees paid to author from Cell Signaling Technologies. T. C. B. reports grants or contracts unrelated to this work from Gilead Sciences, Inc and Fujifilm Pharmaceuticals U.S.A., Inc. Z. Z. reports grants or contracts unrelated to this work. All remaining authors: No reported conflicts of interest. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2022. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Throughout the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, healthcare workers (HCWs) have faced risk of infection from within the workplace via patients and staff as well as from the outside community, complicating our ability to resolve transmission chains in order to inform hospital infection control policy. Here we show how the incorporation of sequences from public genomic databases aided genomic surveillance early in the pandemic when circulating viral diversity was limited., Methods: We sequenced a subset of discarded, diagnostic SARS-CoV-2 isolates between March and May 2020 from Boston Medical Center HCWs and combined this data set with publicly available sequences from the surrounding community deposited in GISAID with the goal of inferring specific transmission routes., Results: Contextualizing our data with publicly available sequences reveals that 73% (95% confidence interval, 63%-84%) of coronavirus disease 2019 cases in HCWs are likely novel introductions rather than nosocomial spread., Conclusions: We argue that introductions of SARS-CoV-2 into the hospital environment are frequent and that expanding public genomic surveillance can better aid infection control when determining routes of transmission., Competing Interests: Potential conflicts of interest. W. P. H. is a member of Biobot Analytics’ scientific advisory board. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2022. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Background: The factors associated with severe acute respiratory coronavirus 2 (SARS-CoV-2) reinfection remain poorly defined., Methods: We identified patients with SARS-CoV-2 infection and at least 1 repeat reverse transcription polymerase chain reaction result a minimum of 90 days after the initial positive test and before 21 January 2021. Those with a repeat positive test were deemed to have reinfection (n = 75), and those with only negative tests were classified as convalescents (n = 1594). Demographics, coronavirus disease 2019 (COVID-19) severity, and treatment histories were obtained from the Boston Medical Center electronic medical record. Humoral responses were analyzed using SARS-CoV-2-specific enzyme-linked immunosorbent assays and pseudovirus neutralizations in a subset of reinfection (n = 16) and convalescent samples (n = 32). Univariate, multivariate, and time to event analyses were used to identify associations., Results: Individuals with reinfection had more frequent testing at shorter intervals compared with the convalescents. Unstable housing was associated with more than 2-fold greater chance of reinfection. Preexisting comorbidities and COVID-19 severity after the initial infection were not associated with reinfection. SARS-CoV-2 immunoglobulin G levels and pseudovirus neutralization were not different within the early weeks after primary infection and at a timepoint at least 90 days later in the 2 groups. In the convalescents, but not in those with reinfection, the late as compared with early humoral responses were significantly higher., Conclusions: Reinfection associates with unstable housing, which is likely a marker for virus exposure, and reinfection occurs in the presence of SARS-CoV-2 antibodies., (© The Author(s) 2021. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Differences in T-cell phenotype, particularly the expression of markers of T-cell homeostasis, have been observed in fatal and nonfatal Ebola virus disease (EVD). However, the relationship between these markers with T-cell function and virus clearance during EVD is poorly understood. To gain biological insight into the role of T cells during EVD, combined transcriptomics and T-cell receptor sequencing was used to profile blood samples from fatal and nonfatal EVD patients from the recent West African EVD epidemic. Fatal EVD was characterized by strong T-cell activation and increased abundance of T-cell inhibitory molecules. However, the early T-cell response was oligoclonal and did not result in viral clearance. In contrast, survivors mounted highly diverse T-cell responses, maintained low levels of T-cell inhibitors, and cleared Ebola virus. Our findings highlight the importance of T-cell immunity in surviving EVD and strengthen the foundation for further research on targeting of the dendritic cell-T cell interface for postexposure immunotherapy.

The domestic ferret is a uniformly lethal model of infection for 3 species of Ebolavirus known to be pathogenic in humans. Reagents to systematically analyze the ferret host response to infection are lacking; however, the recent publication of a draft ferret genome has opened the potential for transcriptional analysis of ferret models of disease. In this work, we present comparative analysis of longitudinally sampled blood taken from ferrets and nonhuman primates infected with lethal doses of the Makona variant of Zaire ebolavirus. Strong induction of proinflammatory and prothrombotic signaling programs were present in both ferrets and nonhuman primates, and both transcriptomes were similar to previously published datasets of fatal cases of human Ebola virus infection.

Summary: High-throughput screening of the host transcriptional response to various viral infections provides a wealth of data, but utilization of microarray and next generation sequencing (NGS) data for analysis can be difficult. The Host Transcriptional Response DataBase (HoTResDB), allows visitors to access already processed microarray and NGS data from non-human primate models of viral hemorrhagic fever to better understand the host transcriptional response., Availability: HoTResDB is freely available at http://hotresdb.bu.edu., (© The Author 2017. Published by Oxford University Press.)

The filoviruses, Marburg marburgvirus (MARV), Zaire ebolavirus (ZEBOV), and Sudan ebolavirus (SEBOV), cause severe and often fatal hemorrhagic fever in humans and nonhuman primates (NHPs). Monovalent recombinant vesicular stomatitis virus (rVSV)-based vaccine vectors, which encode a filovirus glycoprotein (GP) in place of the VSV glycoprotein, have shown 100% efficacy against homologous filovirus challenge in rodent and NHP studies. Here, we examined the utility of a single-vector, single-injection trivalent rVSV vector expressing MARV, ZEBOV, and SEBOV GPs to protect against MARV-, ZEBOV-, and SEBOV-induced disease in outbred Hartley guinea pigs where we observed protection from effects of all 3 filoviruses., (© The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

The mechanisms of Ebola (EBOV) pathogenesis are only partially understood, but the dysregulation of normal host immune responses (including destruction of lymphocytes, increases in circulating cytokine levels, and development of coagulation abnormalities) is thought to play a major role. Accumulating evidence suggests that much of the observed pathology is not the direct result of virus-induced structural damage but rather is due to the release of soluble immune mediators from EBOV-infected cells. It is therefore essential to understand how the candidate therapeutic may be interrupting the disease process and/or targeting the infectious agent. To identify genetic signatures that are correlates of protection, we used a DNA microarray-based approach to compare the host genome-wide responses of EBOV-infected nonhuman primates (NHPs) responding to candidate therapeutics. We observed that, although the overall circulating immune response was similar in the presence and absence of coagulation inhibitors, surviving NHPs clustered together. Noticeable differences in coagulation-associated genes appeared to correlate with survival, which revealed a subset of distinctly differentially expressed genes, including chemokine ligand 8 (CCL8/MCP-2), that may provide possible targets for early-stage diagnostics or future therapeutics. These analyses will assist us in understanding the pathogenic mechanisms of EBOV infection and in identifying improved therapeutic strategies.