Intrahost evolution and forward transmission of a novel SARS-CoV-2 Omicron BA.1 subvariant (preprint)

AO_SCPLOWBSTRACTC_SCPLOWPersistent SARS-CoV-2 infections have been reported in immune-compromised individuals and people undergoing immune-modulatory treatments. It has been speculated that the emergence of antigenically diverse SARS-CoV-2 variants such as the Omicron variant may be the result of intra-host viral evolution driven by suboptimal immune responses, which must be followed by forward transmission. However, while intrahost evolution has been documented, to our knowledge no direct evidence of subsequent forward transmission is available to date. Here we describe the emergence of an Omicron BA.1 sub-lineage with 8 additional amino acid substitutions within the spike (E96D, L167T, R346T, L455W, K458M, A484V, H681R, A688V) in an immune-compromised host along with evidence of 5 forward transmission cases. Our findings show that the Omicron BA.1 lineage can further diverge from its exceptionally mutated genome during prolonged SARS-CoV-2 infection; highlighting an urgent need to employ therapeutic strategies to limit duration of infection and spread in vulnerable patients.

Introductions and early spread of SARS-CoV-2 in the New York City area (preprint)

New York City (NYC) has emerged as one of the epicenters of the current SARS-CoV2 pandemic. To identify the early events underlying the rapid spread of the virus in the NYC metropolitan area, we sequenced the virus causing COVID19 in patients seeking care at the Mount Sinai Health System. Phylogenetic analysis of 84 distinct SARS-CoV2 genomes indicates multiple, independent but isolated introductions mainly from Europe and other parts of the United States. Moreover, we find evidence for community transmission of SARS-CoV2 as suggested by clusters of related viruses found in patients living in different neighborhoods of the city.

A serological assay to detect SARS-CoV-2 seroconversion in humans (preprint)

SARS-Cov-2 (severe acute respiratory disease coronavirus 2), which causes Coronavirus Disease 2019 (COVID19) was first detected in China in late 2019 and has since then caused a global pandemic. While molecular assays to directly detect the viral genetic material are available for the diagnosis of acute infection, we currently lack serological assays suitable to specifically detect SARS-CoV-2 antibodies. Here we describe serological enzyme-linked immunosorbent assays (ELISA) that we developed using recombinant antigens derived from the spike protein of SARS-CoV-2. Using negative control samples representing pre-COVID 19 background immunity in the general adult population as well as samples from COVID19 patients, we demonstrate that these assays are sensitive and specific, allowing for screening and identification of COVID19 seroconverters using human plasma/serum as early as two days post COVID19 symptoms onset. Importantly, these assays do not require handling of infectious virus, can be adjusted to detect different antibody types and are amendable to scaling. Such serological assays are of critical importance to determine seroprevalence in a given population, define previous exposure and identify highly reactive human donors for the generation of convalescent serum as therapeutic. Sensitive and specific identification of coronavirus SARS-Cov-2 antibody titers may, in the future, also support screening of health care workers to identify those who are already immune and can be deployed to care for infected patients minimizing the risk of viral spread to colleagues and other patients.