When is the third dose of the new crown vaccine most effective?
Should the new crown vaccine strengthen the third shot?
If you want to fight when is the best time to fight?
On September 25, Xie Xiaoliang, a foreign academician of the Chinese Academy of Sciences and Li Zhaoji Chair Professor of Peking University, delivered a speech at the 2021 Zhongguancun Forum plenary meeting and pointed out that the comprehensive antibody titers in the blood of the second-shot vaccination patients will be significantly weakened within a few months, but in vivo Immune memory has not been lost. The third dose of booster vaccine will significantly increase the comprehensive antibody titer within seven days and maintain a high level for at least 9 months.
If conditions permit, the third shot is best given six months after the second shot.
Xie Xiaoliang said that the antibody titer marks the resistance of the vaccine. The higher the integrated antibody titer, the better the immunogenicity of the vaccine. After the first shot of the vaccine, the integrated antibody titer in the blood is very low. The second shot The vaccine has increased the overall antibody titer a lot, but it will still decrease with the basic level. Six months after the second injection, it is basically below the detection threshold, which means that breakthrough infection may occur.
"But the human immune system has a memory of the virus." He pointed out that when the third injection is a booster vaccine, the comprehensive antibody titer of the blood will immediately increase significantly and can maintain a high level for at least 9 months. Six months after the second injection, the third injection induced a significant increase in the overall antibody titer compared with the third month after the injection.
According to the data analysis picture displayed by Xie Xiaoliang, the third injection is nine months after the second injection. At this time, the titer of the comprehensive antibody has reached zero, and the human immune memory can be quickly aroused, the peak value of the antibody titer. It is almost the same as the third injection six months later; the effect of the third injection after twelve months is the same as the third injection six months and nine months later.
Xie Xiaoliang emphasized that after a year's interval, the immune memory still exists and can be recalled within seven days.
There is no obvious difference in the peak antibody titer between six, nine, and twelve months. Therefore, if conditions permit, the third dose should be given six months after the second dose.
In his speech, Xie Xiaoliang also compared the effects of the third needle Kexing inactivated vaccine on the original strain and the Delta strain.
The results of the study showed that compared with the original strain, for the Delta strain, it is also the best to start the third injection six months after the second injection, and there is little difference between waiting nine or twelve months for the third injection.
Text/Reporter Cheng Jie