COVID-19 Serology in New York State Using a Multiplex Microsphere Immunoassay (preprint)

The emergence of SARS-CoV-2, leading to COVID-19, necessitated the development of new molecular and serological tests. Here, we describe a multiplexed serological assay developed as the global pandemic moved into New York State in the spring of 2020. The original microsphere immunoassay used a target antigen from the SARS-CoV-1 virus responsible for the 2003 SARS outbreak, but evolved to incorporate multiple SARS-CoV-2 protein antigens (nucleocapsid, spike and spike domains, spike and nucleocapsid proteins from seasonal human coronaviruses). Besides being highly versatile due to multiplex capabilities, the assay was highly specific and sensitive and adaptable to measuring both total antibodies and antibody isotypes. While determining the assay performance characteristics, we were able to identify antibody production patterns (e.g., kinetics of isotypes, individual variations) for total antibodies and individual antibody classes. Overall, the results provide insights into the laboratory response to new serology needs, and how the evolution and fine-tuning of a serology assay helped contribute to a better understanding of the antibody response to SARS-CoV-2.

A randomized, double-blind, controlled trial of convalescent plasma in adults with severe COVID-19 (preprint)

BackgroundAlthough convalescent plasma has been widely used to treat severe coronavirus disease 2019 (COVID-19), data from randomized controlled trials that support its efficacy are limited. ObjectiveTo evaluate the clinical efficacy and safety of convalescent plasma among adults hospitalized with severe and critical COVID-19. DesignRandomized, double-blind, controlled, multicenter, phase 2 trial conducted from April 21st to November 27th, 2020. SettingFive hospitals in New York City (NY, USA) and Rio de Janeiro (Brazil). ParticipantsHospitalized patients aged [≥]18 years with laboratory-confirmed COVID-19, infiltrates on chest imaging and oxygen saturation [≤] 94% on room air or requirement for supplemental oxygen, invasive mechanical ventilation, or extracorporeal membrane oxygenation. InterventionParticipants were randomized 2:1 to a single transfusion of either 1 unit of convalescent or normal control plasma. MeasurementsThe primary outcome was clinical status at 28 days, measured using an ordinal scale and analyzed using a proportional odds model in the intention-to-treat population. ResultsOf 223 participants enrolled, 150 were randomized to receive convalescent plasma and 73 to normal control plasma. At 28 days, no significant improvement in clinical status was observed in participants randomized to convalescent plasma (with an odds ratio (OR) of a 1-point improvement in the scale: 1.50, 95% confidence interval (CI) 0.83-2.68, p=0.180). However, 28-day mortality was significantly lower in participants randomized to convalescent plasma versus control plasma (19/150 [12.6%] versus 18/73 [24.6%], OR 0.44, 95% CI 0.22-0.91, p=0.034). The median titer of anti-SARS-CoV-2 neutralizing antibody in infused convalescent plasma units was 1:160 (IQR 1:80-1:320). In a subset of nasopharyngeal swab samples (n=40) from Brazil that underwent genomic sequencing, no evidence of neutralization-escape mutants was detected. Serious adverse events occurred in 39/147 (27%) participants who received convalescent plasma and 26/72 (36%) participants who received control plasma. LimitationsSome participants did not receive high-titer convalescent plasma. ConclusionIn adults hospitalized with severe COVID-19, use of convalescent plasma was not associated with significant improvement in 28 days clinical status. The significant reduction in mortality associated with convalescent plasma, however, may warrant further evaluation. RegistrationClinicalTrials.gov, NCT04359810 FundingAmazon Foundation Clinical Trial RegistrationClinicalTrials.gov Identifier: NCT04359810

Antibody responses to SARS-CoV2 are distinct in children with MIS-C compared to adults with COVID-19 (preprint)

Clinical manifestations of COVID-19 caused by the novel coronavirus SARS-CoV-2 are associated with age. While children are largely spared from severe respiratory disease, they can present with a SARS-CoV-2-associated multisystem inflammatory syndrome (MIS-C) similar to Kawasaki's disease. Here, we show distinct antibody (Ab) responses in children with MIS-C compared to adults with severe COVID-19 causing acute respiratory distress syndrome (ARDS), and those who recovered from mild disease. There was a reduced breadth and specificity of anti-SARS-CoV-2-specific antibodies in MIS-C patients compared to the COVID patient groups; MIS-C predominantly generated IgG Abs specific for the Spike (S) protein but not for the nucleocapsid (N) protein, while both COVID-19 cohorts had anti-S IgG, IgM and IgA Abs, as well as anti-N IgG Abs. Moreover, MIS-C patients had reduced neutralizing activity compared to COVID-19 cohorts, indicating a reduced protective serological response. These results suggest a distinct infection course and immune response in children and adults who develop severe disease, with implications for optimizing treatments based on symptom and age.

Antibody Testing Documents the Silent Spread of SARS-CoV-2in New York Prior to the First Reported Case (preprint)

We developed and validated serologic assays to determine SARS-CoV-2 seroprevalence in select patient populations in greater New York City area early during the epidemic. We tested “discarded” serum samples from February 24 to March 29 for antibodies against SARS-CoV-2 spike trimer and nucleocapsid protein. Using known durations for antibody development, incubation period, serial interval, and reproductive ratio for this pandemic, we determined that introduction of SARS-CoV-2 into New York likely occurred between January 23 and February 4, 2020. SARS-CoV-2 spread silently for 4–5 weeks before the first community acquired infection was reported. A novel coronavirus emerged in December 2019 in Wuhan, China1,2 and devasted Hubei Province in early 2020 before spreading to every province within China and nearly every country in the world3. This pathogen, now termed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has caused a global pandemic, with ~ 10 million cases and over 500,000 deaths reported through June 30, 20203. The first case of SARS-CoV-2 infection in the United States was identified on January 19, 2020 in a man who returned to the State of Washington from Wuhan4. In the ensuing months, the U.S. has become a hotspot of the pandemic, presently accounting for almost one third of the total caseload and over one fourth of the deaths3. The first confirmed case in New York was reported on March 1 in a traveler recently returned from Iran. The first community-acquired SARS-CoV-2 infection was diagnosed on March 3 in a 50-year-old male who lived in New Rochelle and worked in New York City (https://www1.nyc.gov/site/doh/covid/covid-19-data-archive.page.) In the ensuing 18 weeks, New York City has suffered a peak daily infection number of ~ 4,500 (Fig. 1a) and a cumulative caseload of ~ 400,000 to date. The time period when SARS-CoV-2 gained entry into this epicenter of the pandemic remains unclear.