What is the more effective way to strengthen the needles, strengthen the homologous and strengthen the COVID-19 vaccine? On the 18th, the reporter interviewed Wang Ming, the chief expert of Guangzhou Preventive Medicine Association. He said that heterologous vaccines can play 1 + 1gt; 2. Function of. Because sequential vaccination using different technical paths is expected to increase the intensity, breadth and durability of immune response and bring more comprehensive and effective protection through the complementarity between different mechanisms. The antibody level decreased with the prolongation of inoculation time It has been nearly 1 years since the first New Coronavirus inactivated vaccine (Vero cell) was inoculated in April 12, 2020. With the extension of vaccination time, the neutralizing antibody level of the vaccine and the protective power of the vaccine continue to decline, and breakthrough infections continue to occur. A study by University of Hong Kong showed that the neutralizing antibody titers of the original COVID-19 strain should be treated. After second months of inoculation, the average titer of neutralizing antibody dropped to negative level, and the positive rate of antibody was only 35.2% in the inactivated vaccine after 6 months. What does that mean? "The reduction of neutralizing antibody level will lead to breakthrough infection," Wang Ming said Other technical routes of the new crown vaccine also encountered the same problem. Wang Ming introduced that the results of a study in the United States in 2021 showed that the vaccine protection rate was calculated monthly after vaccination with mRNA vaccine. The effectiveness was more than 90% 3-6 months after vaccination and 65.5% 7 months after vaccination. According to the completion status of vaccination, the breakthrough infection cases in July last year were analyzed hierarchically: the breakthrough infection rate of the people who completed vaccination from January to February last year was 6.7 cases / 1000 people, and the breakthrough infection rate of the people who completed vaccination from March to may last year was 3.7 cases / 1000 people. The decrease of vaccine protection rate was mainly due to the increase of infectivity of delta mutant strain and the decrease of vaccine protection efficacy with the extension of vaccination time. Therefore, with the extension of vaccination time, the antibody level produced by various technical routes of vaccines decreases, so it is imperative to strengthen immunization. Heterologous immunization is used in most countries Wang Ming introduced that at present, the immunization strategies of the new crown vaccine are different all over the world. Most countries adopt heterologous immunization. For example, Germany is the homologous mRNA vaccine-1273 enhanced vaccine, but the UK, the United States, Canada, Chile, Thailand, Brazil, the United Arab Emirates, Peru and Argentina are mainly heterologous immunization. What is homologous enhanced immunity? Wang Ming explained that the same vaccine is used to strengthen vaccination after routine immunization. For example, after 2 doses of inactivated vaccine are inoculated, the third dose is inoculated to strengthen immunity. Heterologous (sequential) immunization is the interval vaccination of vaccines in different technical paths. For example, after completing two doses of inactivated vaccine, one dose of mRNA vaccine or adenovirus vector vaccine is inoculated as enhanced immunization. "In fact, heterologous (sequential) immunization is not a new thing. At present, sequential immunization is adopted for polio vaccine." Wang Ming said. At present, a large number of studies show that heterologous reinforcement has better protection than homologous reinforcement. The research results of Shanghai Huashan Hospital showed that the neutralizing antibody against Omicron was 48.73 14 days after the enhancement of three doses of inactivated Chinese medicine vaccine, while the neutralizing antibody was 95.86 after heterologous enhancement with Zhifei biological recombinant protein subunit vaccine (CHO cells), which showed 100% neutralizing antibody response rate after enhancement, indicating that heterologous enhancement after two doses of inactivated vaccine showed higher vaccine effectiveness than homologous enhancement. This result also appeared in the adenovirus vector vaccine. The kangxinuo study showed that after two doses of inactivated vaccine, one dose of inhaled adenovirus vector vaccine was inoculated as reinforcement. After 14 and 28 days, the GMT of neutralizing antibody was 197.4 and 150.3, and the antibody level increased by about 78.3 and 59.5 times; If the third injection is strengthened with inactivated vaccine, the GMT level of neutralizing antibody is 33.6 and 35.3, which increases by about 15.2 and 15.9 times. The data showed that the growth level of neutralizing antibody produced by heterologous sequential enhancement after the third injection was significantly better than that of homologous enhancement. Recently, Lin Peng, chief expert of Guangdong Center for Disease Control and prevention, also pointed out that strengthening vaccination, especially heterologous vaccination (such as inactivated virus vaccine + recombinant protein subunit vaccine / mRNA vaccine), can significantly improve the titer of neutralizing antibodies in human body. Wang Ming pointed out that at present, different types of vaccines approved all over the world have their own characteristics. For example, the T cell response induced by inactivated vaccine and recombinant protein vaccine is weak; Although adenovirus vector vaccine can induce T cell response, the level of neutralizing antibody is low; MRNA vaccine can not only induce strong humoral immunity, but also activate multi epitope T cell immunity. "If heterologous vaccine is used for booster needle, it can be synergistic and complementary, and can play the protective effect of 1 + 1gt; 2. Because sequential vaccination of vaccines using different technical paths is expected to increase the intensity, breadth and durability of immune response through complementarity between different mechanisms, so as to bring more comprehensive and effective protection." (outlook new era)