Evaluation of COVID-19 Immune Barrier and Reinfection Risk
The goal of this observational study is to evaluate the protective effect of immune barrier on secondary infection after COVID-19 (coronavirus disease 2019) vaccination or COVID-19 virus Omicron B A. 5.2 strain infection by dynamically monitoring the COVID-19 antibody titer, cellular immune function and the occurrence of secondary infection of healthy participants, mainly medical staff in our hospital, to understand the cross protective effect of COVID-19 antibody on different variants of Omicron, and explore the best time to use COVID-19 vaccine to strengthen immunity after Omicron mutant infection.
• No age limit, no gender limit;
• Medical staff, administrative and logistics staff who work in the Third Affiliated Hospital of Sun Yat-Sen University or other participants who can cooperate with the follow-up for 48 weeks;
• The participants need to be sure whether they have ever been infected with COVID-19, and need to be clearly remember the time when they first infected with COVID-19.