Vaccination reduces viral load and accelerates viral clearance in SARS-CoV-2 Delta variant-infected patients.

OBJECTIVE: The purpose of this study was to investigate vaccine effectiveness in relieving symptoms in patients with the SARS-CoV-2 delta (B.1.617.2) variant. METHODS: In this retrospective study, 31 patients did not receive any vaccine (non-vaccination, NV), 21 patients received 1-dose of inactivated vaccine (one-dose vaccination, OV), and 60 patients received at least 2-dose inactivated vaccine (two-dose vaccination, TV). The baseline data, clinical outcomes and vaccination information were collected and analyzed. RESULTS: Patients in the OV group were younger than those in the other two groups (p = 0.001), but there was no significant difference in any of the other baseline data among the three groups. The TV group showed higher IgG antibody levels and cycle threshold values of SARS-CoV-2 than the NV and OV groups (p < 0.01), and time to peak viral load was shorter in the TV group (3.5 ± 2.3 d) than in the NV (4.8 ± 2.8 d) and OV groups (4.8 ± 2.9 d, p = 0.03). The patients in the TV group (18%) showed a higher recovery rate without drug therapy (p < 0.001). Viral clearance time and hospital stay were significantly shorter in the TV group than in the NV and OV groups (p < 0.01), and there were no significant differences in these parameters between the OV and NV groups, but IgG values were higher in the OV group (p = 0.025). No severe complications occurred in this study. CONCLUSIONS: Our results suggest that 2-dose vaccination can reduce viral load and accelerate viral clearance in patients with the delta variant and enhance the protection afforded by IgG antibodies in vivo.Key MessagesIn this study, our results shows that two-dose vaccination can reduce viral loads and accelerate viral clearance, and two-dose vaccination enhance the protection of IgG antibodies in vivo; however, one-dose vaccination did not confer protective effectiveness.

Assessment on Pedestrian-level Wind Around a Pocket Park with and Without Vegetation Inside Street Canyons

Creating a good local microclimate can alleviate urban heat islands and poor urban ventilation. During the COVID-19 epidemic, citizens' cross-city and cross-regional activities were restricted, and most activities were conducted in open/semi-open areas next to residential areas, and local pedestrians were also quantitatively explored. The new characteristics of the microclimate bring difficulties. The RNG k-ε model in the Reynolds time-average method is used to simulate and analyze the wind environment of a typical street valley with a pocket park in a hot summer and a cold winter, and explore whether there are plants in the pocket park. The results show that the results obtained by the used turbulence model, initial edge conditions and numerical method are in good agreement with the selected verification experimental results, which meet the needs of the wind environment simulation of the pocket park. Only under the action of the pocket park, the pedestrian area is dimensionless. The difference in wind speed can reach 0.5 compared to the time when there is no park. When the plants in the park are added, the average wind speed in the pedestrian area of ​​the surrounding street valley is less affected by the plants, and the dimensionless wind speed is only reduced by 0.1 in the core area of ​​the park. Pocket parks can significantly improve the low wind speed in pedestrian areas, and the research results can provide reference for the design of low-carbon livable blocks and microclimate simulation during the epidemic period.