“…Surrogate measures have hence been identified for mirroring the efficacy of the immune response, especially in individuals at higher likelihood of poor immunization (morbid, older, immunosuppressed), or in those at enhanced risk of risk of developing more severe more of illness [9] . The opportunity to assess both arms of the immune response by means of rapid, easy and relatively inexpensive laboratory tests (i.e., cellular immunity using interferon-γ release assay and humoral immunity with SARS-CoV-2 serology, respectively) [10] , is emerging as a valuable asset in both clinical practice and public health. To this end, early recognition of a blunted and or a faster decline of the immune response would enable to reliably identify individuals who may benefit most from additional or closer booster doses, as clearly shown by Achiron et al.…”