Robust humoral and cellular immune responses in long-term convalescent COVID-19 individuals following one-dose SARS-CoV-2 inactivated vaccination

COVID-19, caused by SARS-CoV-2, has resulted in hundreds of millions of infections and millions of deaths worldwide. Preliminary results exhibited excellent efficacy of SARS-CoV-2 vaccine in preventing hospitalization and severe disease. However, data on inactivated vaccine-induced immune responses of naturally infected patients are limited. Here, we characterized SARS-CoV-2 RBD-specific IgG (anti-S-RBD IgG) and neutralizing antibodies (NAbs) against SARS-CoV-2 wild type and variants of concerns (VOCs), as well as RBD-specific IgG-secreting B cells and antigen-specific T cells respectively in 51 SARS-CoV-2 recovered subjects and 63 healthy individuals. In SARS-CoV-2 recovered patients, a single dose vaccine is sufficient to reactivate robust anti-S-RBD IgG and NAbs. The neutralizing capacity against VOCs increased significantly post-vaccination no matter healthy individuals or SARS-CoV-2 recovered patients. In addition, RBD-specific IgG-secreting B cells in SARS-CoV-2 recovered patients were significantly higher than that in healthy vaccine recipients. After the vaccine booster, the frequencies of specific IFN-γ+ CD4+ T cell, IL-2+ CD4+ T cell, and TNF-α+ CD4+ T cell responses were significantly increased in SARS-CoV-2 recovered patients. Our data highlighted the safety and utility of SARS-CoV-2 inactivated vaccine and demonstrated that robust humoral and cellular immune response can be reactivated by one-dose inactivated vaccine in SARS-CoV-2 recovered patients.

Spike mutations in SARS-CoV-2 variants confer resistance to antibody neutralization (preprint)

New SARS-CoV-2 variants continue to emerge from the current global pandemic, some of which can replicate faster and with greater transmissibility and pathogenicity. In particular, UK501Y.V1 identified in UK, SA501Y.V2 in South Africa, and BR501Y.V3 in Brazil are raising serious concerns as they spread quickly and contain spike protein mutations that may facilitate escape from current antibody therapies and vaccine protection. Here, we constructed a panel of 28 SARS CoV 2 pseudoviruses bearing single or combined mutations found in the spike protein of these three variants, as well as additional nine mutations that within or close by the major antigenic sites in the spike protein identified in the GISAID database. These pseudoviruses were tested against a panel of monoclonal antibodies (mAbs), including some approved for emergency use to treat SARS CoV 2 infection, and convalescent patient plasma collected early in the pandemic. SA501Y.V2 pseudovirus was the most resistant, in magnitude and breadth, against mAbs and convalescent plasma, followed by BR501Y.V3, and then UK501Y.V1. This resistance hierarchy corresponds with Y144del and 242-244del mutations in the N-terminal domain as well as K417N/T, E484K and N501Y mutations in the receptor binding domain (RBD). Crystal structural analysis of RBD carrying triple K417N E484K N501Y mutations found in SA501Y.V2 bound with mAb P2C-1F11 revealed a molecular basis for antibody neutralization and escape. SA501Y.V2 and BR501Y.V3 also acquired substantial ability to use mouse and mink ACE2 for entry. Taken together, our results clearly demonstrate major antigenic shifts and potentially broadening the host range of SA501Y.V2 and BR501Y.V3, which pose serious challenges to our current antibody therapies and vaccine protection.

The psychological status of 8817 hospital workers during COVID-19 Epidemic: A cross-sectional study in Chongqing.

BACKGROUND: There was an outbreak of COVID-19 towards the end of 2019 in China, which spread all over the world rapidly. The Chinese healthcare system is facing a big challenge where hospital workers are experiencing enormous psychological pressure. This study aimed to (1) investigate the psychological status of hospital workers and (2) provide references for psychological crisis intervention in the future. METHOD: An online survey was conducted to collect sociodemographic features, epidemic-related factors, results of PHQ-9, GAD-7, PHQ-15, suicidal and self-harm ideation (SSI), and the score of stress and support scales. Chi-square test, t-test, non-parametric, and logistic regression analysis were used to detect the risk factors to psychological effect and SSI. RESULTS: 8817 hospital workers participated in this online survey. The prevalence of depression, anxiety, somatic symptoms, and SSI were 30.2%, 20.7%, 46.2%, and 6.5%, respectively. Logistic regression analysis showed that female, single, Tujia minority, educational background of junior or below, designated or county hospital, need for psychological assistance before or during the epidemic, unconfident about defeating COVID-19, ignorance about the epidemic, willingness of attending parties, and poor self-rated health condition were independent factors associated with high-level depression, somatic symptom, and SSI among hospital workers (P<0.05). LIMITATIONS: This cross-sectional study cannot reveal the causality, and voluntary participation could be prone to selection bias. A modified epidemic-related stress and support scale without standardization was used. The number of hospital workers in each hospital was unavailable. CONCLUSION: There were a high level of psychological impact and SSI among hospital workers, which needed to be addressed. County hospital workers were more severe and easier to be neglected. More studies on cognitive and behavioral subsequence after a public health disaster among hospital workers are needed.

Serum SARS-COV-2 Nucleocapsid Protein：A Sensitivity and Specificity Early Diagnostic Marker for SARS-COV-2 Infection (preprint)

ObjectiveThis study aimed to explore the diagnostic value of serum severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid(N) protein assay in the early stage of SARS-COV-2 infection. MethodSerum N protein in SARS-COV-2 infected patients and non-SARS-COV-2 infected population was measured by enzyme-linked immunosorbent assay (ELISA) double antibody sandwich assay. Colloidal gold immunochromatography assay is used to detect serum N protein antibodies in the above population. Results50 cases of SARS-CoV-2 nucleic acid positive and SARS-CoV-2 antibody negative patients had a serum N protein positive rate of 76%, including 2% with a concentration of 10.00-49.99 pg / mL, 8% with a concentration of 50.00-99.99 pg / mL, 22% with a concentration of 100.00 - 299.99 pg/mL, and 44% with a concentration[≥] 300.00 pg / mL. 37 samples of patients with serum SARS-CoV-2 antibody positive after infection had a serum SARS-CoV-2 N protein positive rate of 2.7%, of which 2.7% had the concentration of 10.00-49.99 pg / mL and 0% had the concentration of 50.00-99.99 pg / mL, 100.00 -299.99 pg / mL, and >300.00 pg / mL. Serum N protein test results of 633 non-SARS-COV-2 infected patients including pregnant women, other respiratory infections, and increased rheumatoid factor were all negative, having a serum N protein concentration less than 10.00 pg/mL, with a specificity of 100%. Using SPSS 19.0 to calculate the receiver operating characteristic curve, the area under the curve was 0.9756 (95% confidence interval 0.9485-1.000, p <0.0001), sensitivity and specificity were 92% (95% confidence interval 81.16% to 96.85%) and 96.84% (95% confidence interval 95.17% to 97.15%). The best CUTOFF value is 1.850 pg / mL. ConclusionThe measurement of SARS-COV-2 serum N protein has a high diagnostic value for the infected patients before the antibody appears, and shortens the window period of serological diagnosis. The laboratory needs to establish an individual CUTOFF value according to purpose of the application.

A preliminary study on the reproductive toxicity of GS-5734 on male mice (preprint)

Background GS-5734 as a novel and promising medicine for COVID-2019, its biological impact on the mammalian reproductive system has not been systematically studied. The aim of this study was to evaluate the effects of GS-5734 on sperm parameters and spermatogenesis in mice. Materials and Methods In this study, GS-5734 was synthesized according to the report. 28 adult male mice were randomly segregated into four groups (n=7 for each group). The group 1 was set as the control group, the group 1, 2, 3 and 4 were administered with GS-5734 at a daily dose of 0, 10, 50, 150 μg/mouse respectively, by intraperitoneal injection for 10 days. On the 7th day after the last injection, the testes and cauda epididymides were collected for HE staining and sperm concentration, motility, morphology analysis. Results The results indicated that after treated with GS-5734, the total sperm count and motile sperm rate showed downward trends, the abnormal sperm rate showed an increasing trend. As compared with the control group, GS-5734 at a daily dose of 150 μg/mouse caused a significant decrease in sperm concentration and motility, and a significant increased of abnormal sperm rate; the 50 μg/mouse drug treatment lead to a significant decrease in sperm motility and an increase in abnormal sperm rate. The HE staining of testicular and epididymal tissues showed that the spermatogenesis of mice was significantly deteriorated with the increasing dosage of GS-5734, especially in the 150 μg/mouse group. Conclusion Our findings suggest that a high dosage of GS-5734 may induce testicular toxicity and result in deterioration of sperm parameters in mice. More investigation on the reproductive toxicity of GS-5734 is required.