Peri-operative SARS-CoV-2 infection increases postoperative mortality. The aim of this study was to determine the optimal duration of planned delay before surgery in patients who have had SARS-CoV-2 infection. This international, multicentre, prospective cohort study included patients undergoing elective or emergency surgery during October 2020. Surgical patients with pre-operative SARS-CoV-2 infection were compared with those without previous SARS-CoV-2 infection. The primary outcome measure was 30-day postoperative mortality. Logistic regression models were used to calculate adjusted 30-day mortality rates stratified by time from diagnosis of SARS-CoV-2 infection to surgery. Among 140,231 patients (116 countries), 3127 patients (2.2%) had a pre-operative SARS-CoV-2 diagnosis. Adjusted 30-day mortality in patients without SARS-CoV-2 infection was 1.5% (95%CI 1.4-1.5). In patients with a pre-operative SARS-CoV-2 diagnosis, mortality was increased in patients having surgery within 0-2 weeks, 3-4 weeks and 5-6 weeks of the diagnosis (odds ratio (95%CI) 4.1 (3.3-4.8), 3.9 (2.6-5.1) and 3.6 (2.0-5.2), respectively). Surgery performed ≥ 7 weeks after SARS-CoV-2 diagnosis was associated with a similar mortality risk to baseline (odds ratio (95%CI) 1.5 (0.9-2.1)). After a ≥ 7 week delay in undertaking surgery following SARS-CoV-2 infection, patients with ongoing symptoms had a higher mortality than patients whose symptoms had resolved or who had been asymptomatic (6.0% (95%CI 3.2-8.7) vs. 2.4% (95%CI 1.4-3.4) vs. 1.3% (95%CI 0.6-2.0), respectively). Where possible, surgery should be delayed for at least 7 weeks following SARS-CoV-2 infection. Patients with ongoing symptoms ≥ 7 weeks from diagnosis may benefit from further delay.

Many SARS CoV-2 serology tests have proven to be less accurate than expected and do not assess antibody function as neutralizing, correlating with protection from reinfection. A new assay technology measuring the interaction of purified SARS CoV-2 spike protein receptor binding domain (RBD) with the extracellular domain of the human ACE2 receptor detects these important antibodies. This cPassTM surrogate virus neutralization test (sVNT) when compared directly with eight SARS CoV-2 IgG serology and two live cell neutralization tests gives similar or improved accuracy for qualitative delineation between positive and negative individuals in a fast, scalable and high throughput assay. The combined data support cPassTM sVNT as a tool for highly accurate SARS CoV-2 immunity surveillance of infected/recovered and/or vaccinated individuals, as well as drug and convalescent donor screening. The data also prevue a novel application for cPassTM sVNT in calibrating the stringency of live cell neutralization tests and its use in longitudinal testing of recovered and/or vaccinated patients.

Background: COVID serological tests are essential to determine the overall seroprevalence of a population, and to facilitate exposure estimates within that population. Methods: We performed a head-to-head assessment of enzyme immunoassays (EIA) and point of care lateral flow assays (POCT) to detect SARS-CoV-2 antibodies. Demographics, symptoms, co-morbidities, treatment, and mortality of patients whose sera was used were also reviewed. Results: Six EIAs (Abbott, Affinity, BioRad, DiaSorin, Euroimmun, and Roche), and six POCTs (BTNX, Biolidics, Deep Blue, Genrui, Getein BioTech, and Innovita) were evaluated for the detection of SARS-CoV-2 antibodies in known COVID-19 infected individuals. Sensitivity of EIAs ranged from 50-100%, with only four assays having overall sensitivities >95% after 21 days post symptom onset. Notably, cross-reactivity with other respiratory viruses (PIV-4 (n=5), hMPV (n=3), rhinovirus/enterovirus (n=1), CoV-229E (n=2), CoV-NL63 (n=2), and CoV-OC43 (n=2) was observed; however, overall specificity for EIAs was good (92-100%; where all but one assay had specificity above 95%). POCTs were 0-100% sensitive >21 days post onset, with specificity ranging from 96-100%. However, many POCTs had faint banding and were often difficult to interpret. Conclusions: Serology assays can detect SARS-CoV-2 antibodies as early as 10 days post onset. Serology assays vary in their sensitivity based on the marker (IgA/M vs. IgG vs. total) and by manufacturer; however, overall only 4 EIA and 4 POCT assays had sensitivities >95% >21 days post symptom onset. Cross-reactivity with other seasonal coronaviruses is of concern. The use of serology assays should not be used for the diagnosis of acute infection, but rather for use in carefully designed serosurveys to facilitate understanding of seroprevalence in a population and to identify previous exposure to SARS-CoV-2.