Do you take off your mask correctly? A survey during COVID-19 pandemic in Ningbo, China.

Guidelines and recommendations from public health authorities related to face masks have been essential for containing the COVID-19 pandemic. A cross-sectional survey was conducted in Ningbo City, China, from April 8 to 12, 2022. We assessed the behavioral differences and correlates of mask usage, primarily mask-removal. We examined public mask-wearing behavior during on-site COVID-19 nucleic acid detection. The survey instrument was developed based on the guidelines issued by the World Health Organization and consisted of demographics, mask-wearing knowledge, and behavior. We analyzed data from 1180 participants; 73.2% demonstrated good mask-wearing knowledge. However, regarding mask-wearing behavior, only 53.7% knew the correct way to remove a mask; 70.3% maintained hand hygiene after touching the outside. Binary logistic regression analyses revealed that health prevention knowledge and free mask distribution were positively associated with two types of mask-wearing behaviors. Most participants used masks during the COVID-19 pandemic; however, mask-removal and hand hygiene were neglected when touching the outside of the mask. More attention must be paid to mask-removal and hand hygiene details. Local health authorities should consider introducing the free distribution of masks.

[Preparation and immungenicity of recombinant protein containing intramolecular adjuvant in SARS-CoV-2 RBD domain].

A fusion protein containing a tetanus toxin peptide, a tuftsin peptide and a SARS-CoV-2S protein receptor-binding domain (RBD) was prepared to investigate the effect of intramolecular adjuvant on humoral and cellular immunity of RBD protein. The tetanus toxin peptide, tuftsin peptide and S protein RBD region were connected by a flexible polypeptide, and a recombinant vector was constructed after codon optimization. The recombinant S-TT-tuftsin protein was prepared by prokaryotic expression and purification. BALB/c mice were immunized after mixed with aluminum adjuvant, and the humoral and cellular immune effects were evaluated. The recombinant S-TT-tuftsin protein was expressed as an inclusion body, and was purified by ion exchange chromatography and renaturated by gradient dialysis. The renaturated protein was identified by Dot blotting and reacted with serum of descendants immunized with SARS-CoV-2 subunit vaccine. The results showed that the antibody level reached a plateau after 35 days of immunization, and the serum antibody ELISA titer of mice immunized with recombinant protein containing intramolecular adjuvant was up to 1:66 240, which was significantly higher than that of mice immunized with S-RBD protein (P < 0.05). At the same time, the recombinant protein containing intramolecular adjuvant stimulated mice to produce a stronger lymphocyte proliferation ability. The stimulation index was 4.71±0.15, which was significantly different from that of the S-RBD protein (1.83±0.09) (P < 0.000 1). Intramolecular adjuvant tetanus toxin peptide and tuftsin peptide significantly enhanced the humoral and cellular immune effect of the SARS-CoV-2 S protein RBD domain, which provideda theoretical basis for the development of subunit vaccines for SARS-CoV-2 and other viruses.

[Preparation of different fragments of SARS-CoV-2 N protein and its application in fluorescence chromatography].

Different fragments of SARS-CoV-2 nucleocapsid (N) protein were expressed and purified, and a fluorescence immunochromatography method for detection of SARS-CoV-2 total antibody was established. The effect of different protein fragments on the performance of the method was evaluated. The N protein sequence was analyzed by bioinformatics technology, expressed in prokaryotic cell and purified by metal ion affinity chromatography column. Different N protein fragments were prepared for comparison. EDC reaction was used to label fluorescence microsphere on the synthesized antigen to construct sandwich fluorescence chromatography antibody detection assay, and the performance was systemically evaluated. Among the 4 prepared N protein fragments, the full-length N protein (N419) was selected as the optimized coating antigen, N412 with 0.5 mol/L NaCl was used as the optimal combination; deleting 91-120 amino acids from the N-terminal of N412 reduced non-specific signal by 87.5%. the linear range of detection was 0.312-80 U/L, the limit of detection was 0.165 U/L, and the accuracy was more than 95%. A fluorescence immunochromatographic detection method for analysis of SARS-CoV-2 total antibody was established by pairing N protein fragments. The detection result achieved 98% concordance with the commercially available Guangzhou Wanfu test strip, which is expected to be used as a supplementary approach for detection of SARS-CoV-2. The assay could also provide experimental reference for improving the performance of COVID-19 antibody detection reagents.

Day-by-day blood pressure variability in hospitalized patients with COVID-19.

In a retrospective analysis, the authors investigated day-by-day blood pressure variability (BPV) and its association with clinical outcomes (critical vs. severe and discharged) in hospitalized patients with COVID-19. The study participants were hospitalized in Tongji Hospital, Guanggu Branch, Wuhan, China, between February 1 and April 1, 2020. BPV was assessed as standard derivation (SD), coefficient of variation (CV), and variability independent of mean (VIM). The 79 participants included 60 (75.9%) severe patients discharged from the hospital after up to 47 days of hospitalization, and 19 (24.1%) critically ill patients transferred to other hospitals for further treatment (n = 13), admitted to ICU (n = 3) or died (n=3). Despite similar use of antihypertensive medication (47.4% vs. 41.7%) and mean levels of systolic/diastolic blood pressure (131.3/75.2 vs. 125.4/77.3 mmHg), critically ill patients, compared with severe and discharged patients, had a significantly (p ≤ .04) greater variability of systolic (SD 14.92 vs. 10.84 mmHg, CV 11.39% vs. 8.56%, and VIM 15.15 vs. 10.75 units) and diastolic blood pressure (SD 9.38 vs. 7.50 mmHg, CV 12.66% vs. 9.80%, and VIM 9.33 vs. 7.50 units). After adjustment for confounding factors, the odds ratios for critical versus severe and discharged patients for systolic BPV were 3.41 (95% confidence interval [CI] 1.20-9.66, p = .02), 4.09 (95% CI 1.14-14.67, p = .03), and 2.81 (95% CI 1.12-7.05, p = .03) for each 5-mmHg increment in SD, 5% increment in CV, and 5-unit increment in VIM, respectively. Similar trends were observed for diastolic BPV indices (p ≤ .08). In conclusion, in patients with COVID-19, BPV was greater and associated with worse clinical outcomes.