htmlOn the afternoon of April 11, the State Council’s Joint Prevention and Control Mechanism held a press conference to introduce the relevant situation. A reporter asked: According to media reports, Chile has received large-scale vaccination since early February, and the vaccination rate is close to 1/3, but the local daily confirmed cases have not fallen but risen. Why does this happen? What implications does this have for current vaccination and epidemic prevention and control?
Chinese Center for Disease Control and Prevention Chief Epidemiology Wu Zunyou: has been updated from World Health Organization COVID-19 pandemic information. We noticed that in January and February this year, the global epidemic showed a period of decline and decline, and then the global epidemic generally rebounded and rebounded again. The rebound was more prominent like India and Brazil. The epidemic in Chile has been in the rising stage of the epidemic from December last year to April this year. At the beginning of December last year, the daily report was about 2,000. By early April this year, the daily report reached 8,000, which means that from December last year to April this year, the epidemic in Chile has been on the rise. Chile began to promote vaccination nationwide in February. By early April, at least one shot was taken, accounting for 25% of the total population, which is not as high as the vaccination rate needed to control the epidemic.
Here I would like to give you two basic concepts of science . Vaccination has two protective effects: first, protection effect is the protective effect on individuals who are vaccinated. The protection effect of , just now, was mentioned by Mr. Liu of Sinovac's . What is evaluated in the Phase III clinical trial is to protect individuals. The antibodies produced by each individual after vaccination can protect themselves. Second, the protection effect is that in the population, when the vaccinated individual reaches a certain proportion, the protection of the population can be formed. Therefore, we call this herd immunity concept. So the concept of herd immunity mentioned in the UK at that time last year is such a concept. The critical value of the vaccination rate required by the group immunization for different infectious diseases is different. The stronger the infectiousness, the higher the proportion of vaccination, the weaker the infectious disease, and the lower the vaccination rate required. For example, the new crown, needs to reach 70% or 80% of the population to produce a population protection effect. If the immunization rate of reaches 10%, 20%, 30%, or even 40%, it can only serve as individual protection and cannot produce herd immunity. It will also occur when a source of infection is introduced. This is why countries around the world are fighting to vigorously promote vaccination, and to achieve the coverage required for herd immunization rate before the next epidemic peak in autumn and winter.
(Source: People's Daily Client)
