Antibody body levels slowly decline over time after inoculation. However, the antibody can still stimulate a strong memory response to elevate antibody level in a short period of time.
No need for people vaccinated within one year to take booster shot: China CDC expert
https://www.globaltimes.cn/page/202108/1230974.shtml
No need for people vaccinated within one year to take booster shot: China CDC expert
https://www.globaltimes.cn/page/202108/1230974.shtml