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【Objective】 To investigate the trend of neutralizing antibody level in plasma donors who received the 3rd shot of inactivated novel coronavirus vaccine. 【Methods】 Three commercial ELISA kits for novel coronavirus neutralization antibody detection, manufactured by Company A, B and C, were chosen and screened by Pseudotype Neutralization Test from December 2021 to June 2022. A total of 410 plasma samples from 64 plasma donors who received the 3rd shot of inactivated novel coronavirus vaccine and there after donated plasma within six months were detected by the selected ELISA kit from July to October, 2022. The data were analyzed by Excel 2013 and SPSS 26 software. 【Results】 The high-throughput ELISA kit for SARS-CoV-2 neutralizing antibody detection, manufactured by Company A, was selected for further antibody titer detection. The mixed plasma titers were 1 337.34, 1 148.89, 852.19, 681.38, 556.44 and 457.19 U/mL from 1 to 6 months, respectively, after the 3rd shot of vaccine. The neutralizing antibody titer level began to increase around 7 days after the 3rd shot of vaccine injection and peaked (peak range: 264.07-2 208.39 U/mL, median: 569.34 U/mL) at 1 month (range: 9-43 days, median: 22 days), and then gradually decreased (P<0.05). 【Conclusion】 The neutralizing antibody titer of plasma donors who received the 3rd shot of inactivated novel coronavirus vaccine began to rise around 7 days after vaccination, which reached the peak value at around 1 month and then gradually decreased.
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ABSTRACT Introduction: Immunogenicity has emerged as a challenge in the development of vaccines against coronavirus disease of 2019 (COVID-19). Immunogenicity is a determinant of the efficacy and safety of vaccines. This systematic review and associated meta-analysis summarized and characterized the immunogenicity of COVID-19 vaccines in randomized controlled trials (RCTs). Methods: Relevant RCTs were systematically sourced from different medical databases in August 2021. The risk ratios and mean differences with 95% confidence intervals were calculated. Results: Of 2,310 papers, 16 RCTs were eligible for review. These RCTs involved a total of 26,698 participants (15,292 males and 11,231 females). The pooled results showed a significant difference in the geometric mean titer between the vaccinated and control groups in favor of the vaccine group after 1 and 2 months of follow-up, for the young age group (18 - < 55y), and with different doses (P < 0.001). The difference in the older age group (>55y) was insignificant (P = 0.24). The seroconversion rate of spike neutralizing antibodies favored the vaccine groups 1 or 2 months after vaccination (P < 0.001). The seroconversion rate of the vaccine group was significantly different (P < 0.001) from that of the control group. Conclusions: Vaccination elicits immunogenicity in the follow-up period for all age groups and at low and large doses. Therefore, people should be encouraged to receive vaccines currently being offered. A boost dose has been asserted for the elderly.
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Aim To explore the feasibility of the micro- dynamic chromogenic method for quantitative detection of bacterial endotoxin in recombinant novel coronavirus vaccine ( CHO cell).Methods The micro-dynamic color method of Limulus reagent was used to establish a bacterial endotoxin standard curve.The dilution factor was determined through interference pre -experiment, the recoverv rate of the endotoxin added to the test so- J lution was determined, and the interference test to complete the quantitative detection test of the bacterial endotoxin content in the test product was performed, and the results were compared with those of the gel-clot method.Results Hie linear range of the concentration of the standard curve was 0.02 to 2.0 EU • mL 1 , and the regression equation of the standard curve was lgT =-0.302 7 lgC +2.858 7( r = 0.998 9).When recombinant novel coronavirus vaccine ( CHO cell) was cliluted 40 times or below, the micro -dynamic chromogenic reagent did not interfere with the bacterial endotoxin agglutination reaction, and the recovery rate was 50% to 200%.The test results were consistent with the gel- clot method.Conclusions The micro-dynamic chromogenic method can be used for the quantitative detection of bacterial endotoxins in recombinant novel coronavirus vaccine ( CHO cell) with accurate results, high sensitivity, and process monitoring.