Environmental Surface Monitoring as a Noninvasive Method for SARS-CoV-2 Surveillance in Community Settings: Lessons from a University Campus Study (preprint)

Environmental testing of high-touch objects is a potential noninvasive approach for monitoring population-level trends of SARS-CoV-2 and other respiratory viruses within a defined setting. We aimed to determine the association between SARS-CoV-2 contamination on high-touch environmental surfaces, community level case incidence, and university student health data. Environmental swabs were collected from January 2022 to November 2022 from high-touch objects and surfaces from five locations on a large university campus in Florida, USA. RT-qPCR was used to detect and quantify viral RNA, and a subset of positive samples was analyzed by viral genome sequencing to identify circulating lineages. During the study period, we detected SARS-CoV-2 viral RNA on 90.7% of 162 tested samples. Levels of environmental viral RNA correlated with trends in community-level activity and case reports from the student health center. A significant positive correlation was observed between the estimated viral gene copy number in environmental samples and the weekly confirmed cases at the university. Viral sequencing data from environmental samples identified lineages contemporaneously circulating in the local community and state based on genomic surveillance data. Further, we detected emerging variants in environmental samples prior to their identification by clinical genomic surveillance. Our results demonstrate the utility of viral monitoring on high-touch environmental surfaces for SARS-CoV-2 surveillance at a community level. In communities with delayed or limited testing facilities, immediate environmental surface testing may considerably inform epidemic dynamics.

A collaborative approach to improving representation in viral genomic surveillance (preprint)

The lack of routine viral genomic surveillance delayed the initial detection of SARS-CoV-2, allowing the virus to spread unfettered at the outset of the U.S. epidemic. Over subsequent months, poor surveillance enabled variants to emerge unnoticed. Against this backdrop, long-standing social and racial inequities have contributed to a greater burden of cases and deaths among minority groups. To begin to address these problems, we developed a new variant surveillance model geared toward building microbial genome sequencing capacity at universities in or near rural areas and engaging the participation of their local communities. The resulting genomic surveillance network has generated more than 1,000 SARS-CoV-2 genomes to date, including the first confirmed case in northeast Louisiana of Omicron, and the first and sixth confirmed cases in Georgia of the emergent BA.2.75 and BQ.1.1 variants, respectively. In agreement with other studies, significantly higher viral gene copy numbers were observed in Delta variant samples compared to those from Omicron BA.1 variant infections, and lower copy numbers were seen in asymptomatic infections relative to symptomatic ones. Collectively, the results and outcomes from our collaborative work demonstrate that establishing genomic surveillance capacity at smaller academic institutions in rural areas and fostering relationships between academic teams and local health clinics represent a robust pathway to improve pandemic readiness. Author summaryGenomic surveillance involves decoding a pathogens genetic code to track its spread and evolution. During the pandemic, genomic surveillance programs around the world provided valuable data to scientists, doctors, and public health officials. Knowing the complete SARS-CoV-2 genome has helped detect the emergence of new variants, including ones that are more transmissible or cause more severe disease, and has supported the development of diagnostics, vaccines, and therapeutics. The impact of genomic surveillance on public health depends on representative sampling that accurately reflects the diversity and distribution of populations, as well as rapid turnaround time from sampling to data sharing. After a slow start, SARS-CoV-2 genomic surveillance in the United States grew exponentially. Despite this, many rural regions and ethnic minorities remain poorly represented, leaving significant gaps in the data that informs public health responses. To address this problem, we formed a network of universities and clinics in Louisiana, Georgia, and Mississippi with the goal of increasing SARS-CoV-2 sequencing volume, representation, and equity. Our results demonstrate the advantages of rapidly sequencing pathogens in the same communities where the cases occur and present a model that leverages existing academic and clinical infrastructure for a powerful decentralized genomic surveillance system.

Antigen test swabs are comparable to nasopharyngeal swabs for sequencing of SARS-CoV-2 (preprint)

Viral genomic surveillance has been integral in the global response to the SARS-CoV-2 pandemic. Surveillance efforts rely on the availability of representative clinical specimens from ongoing testing activities. However, testing practices have recently shifted due to the widespread availability and use of rapid antigen tests, which could lead to gaps in future monitoring efforts. As such, genomic surveillance strategies must adapt to include laboratory workflows that are robust to sample type. To that end, we compare the results of RT-qPCR and viral genome sequencing using samples from positive BinaxNOW COVID-19 Antigen Card swabs (N=555) to those obtained from previously collected nasopharyngeal (NP) swabs used for nucleic acid amplification testing (N=135). We show that swabs obtained from antigen cards are comparable in performance to clinical excess samples from NP swabs, providing a viable alternative. This validation permits the reliable expansion of viral genomic surveillance to cases identified in the clinic or home setting where rapid antigen tests are used.

Early emergence phase of SARS-CoV-2 Delta variant in Florida (preprint)

SARS-CoV-2, the causative agent of COVID-19, emerged in late 2020. The highly contagious B.1.617.2 (Delta) Variant of Concern (VOC) was first identified in October 2020 in India and subsequently disseminated worldwide, later becoming the dominant lineage in the U.S. Despite considerable genomic analysis of SARS-CoV-2 in the U.S., several gaps in the understanding of the local dynamics during early introductions remain, which when elucidated could translate the results of viral genomic epidemiology to actionable mitigation efforts. Here, we explore the early emergence of the Delta variant in Florida, U.S. using phylogenetic analysis of representative Florida and globally sampled genomes. We find multiple independent introductions into Florida primarily from North America and Europe, with a minority originating from Asia. These introductions lead to three distinct clades that demonstrated varying relative rates of transmission and possessed five distinct substitutions that were 3-21 times more prevalent in the Florida sample as compared to the global sample. Our results underscore the benefits of routine viral genomic surveillance to monitor epidemic spread and support the need for more comprehensive genomic epidemiology studies of emerging variants. In addition, we provide a model of epidemic spread of newly emerging VOCs that can inform future public health responses.

Introduction and community transmission of SARS-CoV-2 lineage A.2.5 in Florida with novel spike INDELS (preprint)

SARS-CoV-2 (SC2) variants of concern (VOC) continue to emerge and spread globally, threatening the use of monoclonal antibody therapies and vaccine effectiveness. Several mutations in the SC2 spike glycoprotein have been associated with reduction in antibody neutralization. Genomic surveillance of SC2 variants has been imperative to inform the public health response regarding the use of clinical therapies in specific jurisdictions based on the proportion of particular variants (e.g., Gamma (P.1)) in a region. Florida Department of Health Bureau of Public Health Laboratories (BPHL) performs tiled-amplicon whole genome sequencing for baseline and targeted surveillance of SC2 isolates in Florida from clinical specimens collected from county health departments and hospitals throughout the state. Here, we describe the introduction of SC2 lineage A.2.5 in Florida, which contains S:L452R (a substitution of therapeutic concern) and two novel Spike INDELS, the deletion of 141-143 and ins215AGY, with unknown implications on immune response. The A.2.5 lineage was first detected in Florida among an outbreak at a healthcare facility in January 2021, and subsequent A.2.5 isolates were detected across all geographical regions throughout the state. A time-scaled maximum clade credibility phylogeny determined there were at least eight separate introductions of A.2.5 in the state. The time of introduction of a monophyletic Florida clade was established to be December 2020. The Spike INDELS were determined to reside in the N-terminal domain, a region associated with antibody neutralization. As community transmission of SARS-CoV-2 in Florida continues, genomic surveillance of circulating variants in Florida and the detection of emerging variants are critical for informing public health response to COVID-19.

SARS-CoV-2 shifting transmission dynamics and hidden reservoirs limited the efficacy of public health interventions in Italy (preprint)

We investigated SARS-CoV-2 transmission dynamics in Italy, one of the countries hit hardest by the pandemic, using phylodynamic analysis of viral genetic and epidemiological data. We observed the co-circulation of at least 13 different SARS-CoV-2 lineages over time, which were linked to multiple importations and characterized by large transmission clusters concomitant with a high number of infections. Subsequent implementation of a three-phase nationwide lockdown strategy greatly reduced infection numbers and hospitalizations. Yet we present evidence of sustained viral spread among sporadic clusters acting as "hidden reservoirs" during summer 2020. Mathematical modelling shows that increased mobility among residents eventually catalyzed the coalescence of such clusters, thus driving up the number of infections and initiating a new epidemic wave. Our results suggest that the efficacy of public health interventions is, ultimately, limited by the size and structure of epidemic reservoirs, which may warrant prioritization during vaccine deployment.