At the press conference of the joint prevention and control mechanism of the State Council held on February 19, Wu Liang, deputy director of the Bureau of disease control of the National Health Commission, introduced that for the enhanced vaccination of covid-19 vaccine, sequential enhanced immunization has been deployed.
Previously, target people over 18 years old who have been vaccinated with inactivated vaccines of Sinopharm Zhongsheng Beijing company, Wuhan company and Beijing Kexing company, as well as adenovirus vector vaccine of Tianjin Cansino Biologics Inc(688185) company for 6 months can receive one dose of secondary homologous booster immunization, that is, the original vaccine can be used for booster immunization.
After the implementation of the sequential booster immunization strategy, the target population who has completed the whole process of vaccination with the above three inactivated vaccines can also choose the recombinant protein vaccine of zhifeilongke horse or Cansino Biologics Inc(688185) adenovirus vector vaccine for sequential booster immunization. For the target population, select one of homologous booster immunization and sequential booster immunization.
In addition, the joint prevention and control mechanism of the State Council also approved the homologous enhanced immunization of covid-19 virus inactivated vaccine of Shenzhen Kangtai company and the Institute of biology of the medical college.
Wu Liangyou said that the research data show that both homologous enhanced immunity and sequential enhanced immunity can further improve the immune effect.
Previously, Zhang Wenhong and other researchers published a study in emerging microorganisms & infections, saying that on the 14th day after the homologous enhanced vaccination of the inactivated vaccine of Sinopharm Zhongsheng Beijing company, after the pseudovirus neutralization test (pvnt), its effects on the original strain, beta The geometric mean titers (gmts) of neutralizing antibodies of delta and Omicron increased to 285.6, 215.7, 250.8 and 48.73 respectively, while on the 14th day after heterologous booster vaccination with Chongqing Zhifei Biological Products Co.Ltd(300122) recombinant protein subunit vaccine, the corresponding titers increased to 1436.00, 789.6, 1501.00 and 95.86 respectively.
Shao Yiming, member of the expert group of the vaccine research and development special class of the scientific research group of the joint prevention and control mechanism of the State Council, introduced that previously, 759 cases of Omicron virus infection were reported in Tianjin and Anyang, and only 4 severe cases occurred in Tianjin. There were no severe cases in Anyang transmission chain, and the incidence of severe cases was only about 0.6%, which showed that the symptoms caused by Omicron itself were relatively mild. However, the study also found that within 6 months after the completion of immunization, the risk of pneumonia (ordinary type and above) of covid-19 virus infected persons can be reduced by 60%. In the close contact population, the breakthrough infection rates of completing basic immunization and strengthening immunization were 22.6% and 6.0% respectively. Strengthening immunization can reduce the breakthrough infection rate of Omicron by more than 3 times compared with basic immunization.
From the perspective of the world, many regions have begun to carry out sequential vaccination. Wang Huaqing, chief expert of immunization planning of China CDC, introduced that some countries in the Americas, Europe and Southeast Asia have implemented sequential immunization, and the World Health Organization also supports flexible homologous and heterologous vaccination plans.
According to the data of the National Health Commission, as of February 18, the cumulative number of covid-19 virus vaccines vaccinated in China was 3 billion 75752000 doses, and the number of people who completed the whole vaccination process was 1.23543 billion.
