COVID-19 vaccination boosts the potency and breadth of the immune response against SARS-CoV-2 among recovered patients in Wuhan.

The immunity of patients who recover from coronavirus disease 2019 (COVID-19) could be long lasting but persist at a lower level. Thus, recovered patients still need to be vaccinated to prevent reinfection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or its mutated variants. Here, we report that the inactivated COVID-19 vaccine can stimulate immunity in recovered patients to maintain high levels of anti-receptor-binding domain (RBD) and anti-nucleocapsid protein (NP) antibody titers within 9 months, and high neutralizing activity against the prototype, Delta, and Omicron strains was observed. Nevertheless, the antibody response decreased over time, and the Omicron variant exhibited more pronounced resistance to neutralization than the prototype and Delta strains. Moreover, the intensity of the SARS-CoV-2-specific CD4+ T cell response was also increased in recovered patients who received COVID-19 vaccines. Overall, the repeated antigen exposure provided by inactivated COVID-19 vaccination greatly boosted both the potency and breadth of the humoral and cellular immune responses against SARS-CoV-2, effectively protecting recovered individuals from reinfection by circulating SARS-CoV-2 and its variants.

An IgM-like Inhalable ACE2 fusion protein broadly neutralizes SARS-CoV-2 (preprint)

Many of the currently available COVID-19 vaccines and therapeutics are not effective against newly emerged SARS-CoV-2 variants. Here, we developed the metallo-enzyme domain of angiotensin converting enzyme 2 (ACE2)—the cellular receptor of SARS-CoV-2—into an IgM-like inhalable molecule (HH-120). HH-120 binds to the SARS-CoV-2 Spike (S) protein with exceptionally high avidity and confers potent and broad-spectrum neutralization activity against all known SARS-CoV-2 variants of concern. HH-120 was successfully developed as an inhaled formulation that achieves appropriate aerodynamic properties for respiratory system delivery, and we found that aerosol inhalation of HH-120 significantly reduced viral loads and lung pathology scores in golden Syrian hamsters infected by the SARS-CoV-2 wild-type strain and the Delta variant. Our study presents a breakthrough for the inhalation delivery of large biologics like HH-120 (molecular weight ~ 1000kDa) and demonstrates that HH-120 can serve as a highly efficacious, safe, and convenient agent against all SARS-CoV-2 variants. Finally, given the known role of ACE2 in viral reception, it is conceivable that HH-120 will be efficacious against additional emergent coronaviruses.

Potent Anti-SARS-CoV-2 Efficacy of COVID-19 Hyperimmune Globulin from Vaccine-Immunized Plasma.

Coronavirus disease 2019 (COVID-19) remains a global public health threat. Hence, more effective and specific antivirals are urgently needed. Here, COVID-19 hyperimmune globulin (COVID-HIG), a passive immunotherapy, is prepared from the plasma of healthy donors vaccinated with BBIBP-CorV (Sinopharm COVID-19 vaccine). COVID-HIG shows high-affinity binding to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) protein, the receptor-binding domain (RBD), the N-terminal domain of the S protein, and the nucleocapsid protein; and blocks RBD binding to human angiotensin-converting enzyme 2 (hACE2). Pseudotyped and authentic virus-based assays show that COVID-HIG displays broad-spectrum neutralization effects on a wide variety of SARS-CoV-2 variants, including D614G, Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), Kappa (B.1.617.1), Delta (B.1.617.2), and Omicron (B.1.1.529) in vitro. However, a significant reduction in the neutralization titer is detected against Beta, Delta, and Omicron variants. Additionally, assessments of the prophylactic and treatment efficacy of COVID-HIG in an Adv5-hACE2-transduced IFNAR-/- mouse model of SARS-CoV-2 infection show significantly reduced weight loss, lung viral loads, and lung pathological injury. Moreover, COVID-HIG exhibits neutralization potency similar to that of anti-SARS-CoV-2 hyperimmune globulin from pooled convalescent plasma. Overall, the results demonstrate the potential of COVID-HIG against SARS-CoV-2 infection and provide reference for subsequent clinical trials.

Twelve-month specific IgG response to SARS-CoV-2 receptor-binding domain among COVID-19 convalescent plasma donors in Wuhan.

To investigate the duration of humoral immune response in convalescent coronavirus disease 2019 (COVID-19) patients, we conduct a 12-month longitudinal study through collecting a total of 1,782 plasma samples from 869 convalescent plasma donors in Wuhan, China and test specific antibody responses. The results show that positive rate of IgG antibody against receptor-binding domain of spike protein (RBD-IgG) to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the COVID-19 convalescent plasma donors exceeded 70% for 12 months post diagnosis. The level of RBD-IgG decreases with time, with the titer stabilizing at 64.3% of the initial level by the 9th month. Moreover, male plasma donors produce more RBD-IgG than female, and age of the patients positively correlates with the RBD-IgG titer. A strong positive correlation between RBD-IgG and neutralizing antibody titers is also identified. These results facilitate our understanding of SARS-CoV-2-induced immune memory to promote vaccine and therapy development.

Predicted non-effect concentrations for disinfection by-products of haloacetic acids(HAAS) in freshwater environment in China

During the COVID-19, excessive use of disinfectants led to a large amount of disinfection by-products(DBPs) entering natural waters, which could have an adverse effect on the freshwater eco-environment. Five kinds of haloacetic acids(HAAs), including monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid, and dibromoacetic acid, were studied. According to the EU Technical Guidance Document on Risk Assessment, the values of PNEC of 5 HAAs were derived in the water and sediment with the toxicity data of native species in China using assessment factors and equilibrium method,respectively. The results show that the acute and chronic toxicity of the 5 HAAs to aquatic organism were both in the order of monobromoacetic acid > monochloroacetic acid >dichloroacetic acid > trichloroacetic acid > dibromoacetic acid. The PNEC values of five HAAs for water(PNECw) were 0.025,0.030,0.060,0.016 and 1.956 mg/L,respectively;for sediment(PNECs) are 0.021,0.026,0.057,0.013 and 1.679 mg/kg(by wet weigh),respectively. This research shows that the DBPs in the effluents of wastewater treatment plants may pose potential risks and harms to the aquatic environment. Therefore, the monitoring and removal of five HAAs in the effluents of the WWTPs should be improved to reduce the concentration of HAAs discharged into natural waters.

Is Trump a Symptom or a Cause? Economic, Political and Ideological Foundations of the COVID-19 Outbreak in the United States (First Draft) (preprint)

The US is amongst the worst-performing countries at combating COVID-19. And within the US, red (Republican) states have significantly higher cases per capita than blue (Democratic) states. We use cross-country, state, and county-level data to provide a comprehensive analysis of economic, political, and psychological factors contributing to these differences. An inferior social safety net and American conservatism systematically correlate with the realization and effectiveness of non-pharmaceutical interventions such as social distancing and mask wearing from April to September. Economic inequality and weak social safety nets drive the economically vulnerable to work outside their homes, increasing mobility and reducing social distancing during early stages of the pandemic. Conservative ideology, anti-intellectualism, and evangelicalism drive people to politicize social distancing and mask wearing. Both factors predict a premature reopening in many states, and have a strong correlation with the drifting of COVID-19 epicenters to red states over the course of 2020. These factors have more explanatory power than partisanship in the first half year of the COVID-19 outbreak in the United States. However, from October on, closer to the presidential elections, partisanship is a better predictor of anti-COVID measures and explains well the regional variances of confirmed cases across states and counties. This indicates that partisanship is not the solely important factor in determining COVID-19 response and outcome, but its impact is likely to have been magnified as time goes by.

Effectiveness of convalescent plasma therapy in severe COVID-19 patients.

Currently, there are no approved specific antiviral agents for novel coronavirus disease 2019 (COVID-19). In this study, 10 severe patients confirmed by real-time viral RNA test were enrolled prospectively. One dose of 200 mL of convalescent plasma (CP) derived from recently recovered donors with the neutralizing antibody titers above 1:640 was transfused to the patients as an addition to maximal supportive care and antiviral agents. The primary endpoint was the safety of CP transfusion. The second endpoints were the improvement of clinical symptoms and laboratory parameters within 3 d after CP transfusion. The median time from onset of illness to CP transfusion was 16.5 d. After CP transfusion, the level of neutralizing antibody increased rapidly up to 1:640 in five cases, while that of the other four cases maintained at a high level (1:640). The clinical symptoms were significantly improved along with increase of oxyhemoglobin saturation within 3 d. Several parameters tended to improve as compared to pretransfusion, including increased lymphocyte counts (0.65 × 109/L vs. 0.76 × 109/L) and decreased C-reactive protein (55.98 mg/L vs. 18.13 mg/L). Radiological examinations showed varying degrees of absorption of lung lesions within 7 d. The viral load was undetectable after transfusion in seven patients who had previous viremia. No severe adverse effects were observed. This study showed CP therapy was well tolerated and could potentially improve the clinical outcomes through neutralizing viremia in severe COVID-19 cases. The optimal dose and time point, as well as the clinical benefit of CP therapy, needs further investigation in larger well-controlled trials.

Association of Population Migration and Coronavirus Disease 2019 Epidemic Control (preprint)

Background and Objective To analyze the impact of different patterns of migration flow in two cities, Hefei and Shenzhen, on the epidemic and disease control of Coronavirus Disease 2019 (COVID-19), in order to provide insight for making differentiated controlling policies. Methods We collected demographic and epidemiological information of confirmed COVID-19 cases in Hefei and Shenzhen between January 19 and February 11, 2020, from data officially published by the provincial and municipal Centers for Disease Control and Prevention (CDC). From these data we calculated basic reproduction number R0 to reflect the rate of spread of COVID-19 in these cities. Aggregated data of population migration during the same period was extracted from Baidu Migration. The change of R0 in the two cites were analyzed and compared. Spearman correlation analysis between R0 and population inflow from epidemic focus were performed. Results A total of 157 confirmed cases was identified in Hefei by 24:00 February 11, 2020, with an average age of 44.4{+/-}15.6 years, 74 female (47.1%) and 386 confirmed cases were identified in Shenzhen, with an average age of 45.15{+/-}17.99 years, 202 female (52.3%). Significant difference in the proportion of imported cases between the two cities was observed (Hefei vs Shenzhen, 24.2% vs 74.9%, p=0.000). Before January 31 2020, during the initial stage of the Level 1 Response to Major Public Health Emergencies, there was no significant association observed in Shenzhen between R0 and the proportion of population inflow from the epidemic focus (P =0.260, r=-0.452); meanwhile in Hefei, such association was strong (P =0.000, r=1.0). However, after the initial stage of response, the situation reversed. A weak association was observed in Shenzhen between be R0 and the proportion of population inflow from the epidemic focus (P=0.073, r=0.536) but not in Hefei (P =0.498, r=0.217). Conclusion Following Level 1 Response, consistent decline of R0 of COVID-19 was observed in both Hefei and Shenzhen. Different patterns of disease spread were observed in the two cities, driven by different patterns of population migration. This indicated that population migration should be taken into consideration when we set controlling policy of a novel infectious disease.