Material and methods
Blood samples were collected before the administration of the bivalent
booster from Pfizer-BioNTech and after 14, 28, 90, and 180 days.
Neutralizing antibodies against either the D614G strain, the delta
variant, the BA.5 variant, or the XBB.1.5 subvariant were measured. The
cellular response was assessed by measurement of the release of
interferon gamma (IFNγ) from T cells
in response to an in vitro SARS-CoV-2 stimulation.