Evaluation of commercial Anti-SARS-CoV-2 neutralizing antibody assays in seropositive subjects.

The virus neutralization test (VNT) is the reference for the assessment of the functional ability of neutralizing antibodies (NAb) to block SARS-CoV-2 entry into cells. New competitive immunoassays measuring antibodies preventing interaction between the spike protein and its cellular receptor are proposed as surrogate VNT (sVNT). We tested three commercial sVNT (a qualitative immunochromatographic test and two quantitative immunoassays named YHLO and TECO) together with a conventional anti-spike IgG assay (bioMérieux) in comparison with an in-house plaque reduction neutralization test (PRNT50) using the original 19A strain and different variants of concern (VOC), on a panel of 306 sera from naturally-infected or vaccinated patients. The qualitative test was rapidly discarded because of poor sensitivity and specificity. Areas under the curve of YHLO and TECO assays were, respectively, 85.83 and 84.07 (p-value >0.05) using a positivity threshold of 20 for PRNT50, and 95.63 and 90.35 (p-value =0.02) using a threshold of 80. However, the performances of YHLO and bioMérieux were very close for both thresholds, demonstrating the absence of added value of sVNT compared to a conventional assay for the evaluation of the presence of NAb in seropositive subjects. In addition, the PRNT50 assay showed a reduction of NAb titers towards different VOC in comparison to the 19A strain that could not be appreciated by the commercial tests. Despite the good correlation between the anti-spike antibody titer and the titer of NAb by PRNT50, our results highlight the difficulty to distinguish true NAb among the anti-RBD antibodies with commercial user-friendly immunoassays.

Evaluation of Commercial Anti-SARS-CoV-2 Antibody Assays and Comparison of Standardized Titers in Vaccinated Health Care Workers.

With the availability of vaccines, commercial assays detecting anti-severe acute respiratory syndrome coronavirus-2 antibodies (Ab) evolved toward quantitative assays directed to the spike glycoprotein or its receptor binding domain (RBD). The main objective of the present study was to compare the Ab titers obtained with quantitative commercial binding Ab assays, after one dose (convalescent individuals) or two doses (naive individuals) of vaccine, in health care workers (HCW). Antibody titers were measured in 255 sera (from 150 HCW) with five quantitative immunoassays (Abbott RBD IgG II quant, bioMérieux RBD IgG, DiaSorin Trimeric spike IgG, Siemens Healthineers RBD IgG, Wantai RBD IgG). One qualitative total antibody anti-RBD detection assay (Wantai) was used to detect previous infection before vaccination. The results are presented in binding Ab units (BAU)/mL after application, when possible, of a conversion factor provided by the manufacturers and established from a World Health Organization internal standard. There was a 100% seroconversion with all assays evaluated after two doses of vaccine. With assays allowing BAU/mL correction, Ab titers were correlated (Pearson correlation coefficient, ρ, range: 0.85-0.94). The titer differences varied by a mean of 10.6% between Siemens and bioMérieux assays to 60.9% between Abbott and DiaSorin assays. These results underline the importance of BAU conversion for the comparison of Ab titer obtained with the different quantitative assays. However, significant differences persist, notably, between kits detecting Ab against the different antigens. A true standardization of the assays would be to include the International Standard in the calibration of each assay to express the results in IU/mL.

Psychological effect of COVID-19 pandemic among women undergoing infertility care, a French cohort - PsyCovART Psychological effect of COVID-19: PsyCovART.

PURPOSE: To assess psychological state of women who experienced postponement of ART care during the first COVID-19 wave in a French public ward of reproductive medicine. METHODS: An online anonymous survey was emailed between July and August 2020 to all women whose infertility care, including the first consultation for infertility, have been delayed at the beginning of the COVID-19 pandemic. Anxiety, depression, and stress were assessed using Hospital Anxiety and Depression Scale (HADS) and Perceived Stress Scale (PSS-10). Feelings about COVID-19 outbreak, lockdown and suspension of fertility care were assessed by Multiple-Choice Questions and Visual Analog Scales. RESULTS: 435 women answered to the survey (response rate 34.6%). Mean levels of the HADS-A (anxiety), HADS-D (depression) and PSS10 were respectively 7.58(±3.85), 4.51(±3.48), and 27(±6.75). Prevalence of stress was 50.8% and almost half of women presented clear or suggestive anxiety symptoms (respectively 21.6% and 25.7%). Stress and anxiety rates were much higher than those expected in infertile population. Increased stress was observed in women above 35 years and those stopped 'in cycle' or during pre-treatment for in-vitro fertilization or frozen embryo transfer. Patient with history of depression or anxiety had a higher prevalence of perceived stress (p = 0.0006). Postponement was perceived as 'unbearable' for women experiencing stress (p = 0.0032). After the first wave of pandemic, pregnancy desire remained the same and 84.3% of women wanted to resume fertility care as soon as possible. CONCLUSION: Stopping fertility care during the COVID-19 pandemic had a significant psychological impact on women with an increase of stress, and anxiety. Psychological counseling should always be offered especially during this difficult period.