The emerging COVID-19 pandemic caused by SARS-CoV-2 infection has created a global crisis.Under the circumference of no effective treatment or vaccine,the Chinese government has implemented multifaceted mea-sures of social distancing,home isolation,and centralized quarantine,which achieved a remarkable result of controlling the COVID-19 outbreak [1].However,the personal,psychological,economic,and societal conse-quences of the shutdown and physical distancing make it difficult to sustain these public health interventions for a long time [2].To find a new balance between curbing the pandemic and minimizing the indirect effects on society,a better understanding of adaptive immunity in response to SARS-CoV-2 infection is required.Monitoring B cell and T cell immunological memory activated by SARS-CoV-2 over a prolonged period is essential in anticipating durable protection after infection and in developing vaccines.If maintained at sufficiently high levels,the immune response could effectively block re-infection,which might confer long-lived protection [3,4].Even though,the case report of re-infection with completely different SARS-CoV-2 strains from the first episode [5] raised widespread public concern for the “immune passport” and virus mutation.Despite the urgent need to answer these crucial scientific questions,limited studies have systemically evaluated the long-term humoral and cellular immunity.