BACKGROUND
XBC.1 variant of SARS-CoV-2 is showing an increasing trend in countries located in North America, Europe, Asia and Australia.1As per European Centre for Disease Prevention and Control, XBC.1 is designated as a variant under monitoring.2 L452M and F486P are two important mutations in the XBC.1 spike protein within the receptor binding domain (RBD). It has been found that L452M and F486P enhance the infectivity; this may also impact the potency of SARS-CoV-2 vaccines which are based on spike protein.3,4 Since the RBD-Human Angiotensin Converting Enzyme 2 (hACE2) interaction enables viral entry into the human cells, SARS-CoV-2 infectivity may be affected by the substitution of amino acids in the spike protein RBD region.4,5