Omicron-specific mRNA vaccine induced potent neutralizing antibody against Omicron but not other SARS-CoV-2 variants

The emerging SARS-CoV-2 variants of concern (VOC) harbor mutations associated with increasing transmission and immune escape, hence undermine the effectiveness of current COVID-19 vaccines. In late November of 2021, the Omicron (B.1.1.529) variant was identified in South Africa and rapidly spread across the globe. It was shown to exhibit significant resistance to neutralization by serum not only from convalescent patients, but also from individuals receiving currently used COVID-19 vaccines with multiple booster shots. Therefore, there is an urgent need to develop next generation vaccines against VOCs like Omicron. In this study, we develop a panel of mRNA-LNP-based vaccines using the receptor binding domain (RBD) of Omicron and Delta variants, which are dominant in the current wave of COVID-19. In addition to the Omicron- and Delta-specific vaccines, the panel also includes a "Hybrid" vaccine that uses the RBD containing all 16 point-mutations shown in Omicron and Delta RBD, as well as a bivalent vaccine composed of both Omicron and Delta RBD-LNP in half dose. Interestingly, both Omicron-specific and Hybrid RBD-LNP elicited extremely high titer of neutralizing antibody against Omicron itself, but few to none neutralizing antibody against other SARS-CoV-2 variants. The bivalent RBD-LNP, on the other hand, generated antibody with broadly neutralizing activity against the wild-type virus and all variants. Surprisingly, similar cross-protection was also shown by the Delta-specific RBD-LNP. Taken together, our data demonstrated that Omicron-specific mRNA vaccine can induce potent neutralizing antibody response against Omicron, but the inclusion of epitopes from other variants may be required for eliciting cross-protection. This study would lay a foundation for rational development of the next generation vaccines against SARS-CoV-2 VOCs.

Analyzing the abnormal results of personal dose monitoring of medical radiation workers / 中国职业医学

OBJECTIVE: To analyze the abnormal results and their causes of personal dose monitoring on medical radiation workers.METHODS: The medical radiation workers monitored from 2016 to 2019 in the personal dose monitoring room of Guangdong Province Hospital for Occupational Disease Prevention and Treatment were selected as the study subjects using convenient sampling method. The abnormal results and their causes of the medical radiation workers with personal dose equivalent ≥1.25 mSv(investigation level) in a single period were analyzed. RESULTS: The rate of abnormal results of personal dose monitoring was 0.26%(263/102 284). The false result rate was 0.19%(194/102 284), and that of the true result rate was 0.07%(69/102 284). A total of 73.38%(193/263) of medical radiation workers had abnormal results with an personal dose equivalent less than 5.00 mSv. Among different occupational groups, the abnormal results and false results in personal dose monitoring in interventional radiology group were the highest(all P<0.01). The abnormal result rate and false result rate were higher in the Pearl River Delta area than that in the non-Pearl River Delta area(0.27% vs 0.17%, 0.20% vs 0.12%, all P<0.05). The rate of false result of personal dose monitoring in the tertiary hospitals was lower than that in the non-tertiary hospitals(0.18% vs 0.30%, P<0.05). The main reason for the true results of personal dose monitoring was the increase of workload(43.48%), and the main reason for the false results was that the dosimeter was left in the workplace(57.73%). CONCLUSION: The rate of abnormal results of personal dose monitoring in the medical radiation workers is high. Radiological protection should be strengthened with emphasis on medical radiation workers in interventional radiology, Pearl River Delta area hospitals and non-tertiary hospitals.

Effect of power-frequency electromagnetic fields on antioxidant indexes in operation personnel / 中国职业医学

OBJECTIVE: To investigate the effect of the power-frequency electromagnetic field on antioxidant indexes in operation personnel. METHODS: By random sampling method,a total of 58 workers who work in 500 kV transformer substations for at least 5. 0 years were selected as the exposure group,and 60 administrative staffs in the same enterprise were included as the control group. The power frequency electromagnetic fields in the 2 groups were measured. The cumulative exposure dose of individual magnetic field was calculated. Peripheral venous blood was collected in these 2groups and was examined with the superoxide dismutase( SOD) activity,malondialdehyde( MDA) level and the relative gene expression level of manganese superoxide dismutase( MnSOD). RESULTS: There was no statistical significance in the SOD activity,MDA level and the relative gene expression level of MnSOD between the exposure group and the control group( P > 0. 05). The logistic regression analysis results indicated that cumulative exposure dose was not correlated with the SOD activity,MDA level and the relative gene expression level of MnSOD after adjusting confounding factors such as age,smoking,alcohol and tea drinking( P > 0. 05). CONCLUSION: Power-frequency electromagnetic field exposure has no significant effects on the SOD activity,MDA level and the relative gene expression level of MnSOD of operation workers.

Analysis on micronucleus of peripheral blood lymphocytes in workers exposed to power frequency electromagnetic fields / 中国职业医学

OBJECTIVE: To examine the effects of long-term exposure to power frequency electromagnetic fields on the occurrence of micronucleus in peripheral blood lymphocytes and the lymphocyte transformation in transformer substation workers. METHODS: By simple random sampling method,54 workers exposed to power frequency electromagnetic fields for more than 1. 0 year and other 54 non-exposure workers in 500 kV transformer substations were chosen as the exposure group and control group,respectively. The peripheral venous blood of subjects in these two groups was collected,and then the lymphocytes were separated. The micronucleus cell rate,the micronucleus rate and the lymphocyte transformation rate were detected and analyzed. RESULTS: Compared with the control group,the micronucleated cell rate,the micronucleus rate,and the lymphocyte transformation rate of the exposure group and its different length of service subgroups( ≤ 10. 0and > 10. 0 years) showed no statistical significance respectively( P > 0. 05). CONCLUSION: The long-term exposure to power frequency electromagnetic fields has no obvious effects on the micronucleus and lymphocyte transformation in the peripheral blood lymphocytes of exposed workers.

Effects of exposure to power frequency electromagnetic fields on humoral immune function in transformer substation workers / 中国职业医学

OBJECTIVE: To explore the effects of long-term exposure to power frequency electromagnetic fields on the humoral immune function in transformer substation workers. METHODS: By simple random sampling method,64 workers with length of service longer than 5. 0 years in 500 k V transformer substation were chosen as exposure group and 57 general administrative staffs without exposure to power frequency electromagnetic field were chosen as control group. Venous blood was collected from subjects of these two groups and the levels of immunoglobulin( Ig) A,Ig G,Ig M,complement( C) 3and C4 in plasma were examined by immunoturbidimetry. RESULTS: Compared with the control group,the levels of both Ig A and Ig G increased( P < 0. 05),while both levels of C3 and C4 decreased( P < 0. 05) in exposure group. Compared with the control,the level of Ig G increased( P < 0. 05),while the levels of both C3 and C4 decreased( P < 0. 05) in exposure subgroup with length of service ≤10. 0 years. The level of C4 decreased( P < 0. 05) in exposure subgroup with length of service > 10. 0 years. CONCLUSION: Long-term exposure to power frequency electromagnetic fields may activate the humoral immune function in transformer substation workers.