Lack of SARS-CoV-2-specific cellular response despite apparent effective vaccination
Measuring antibodies which bind viruses to tag them for destruction and antibodies which stop viruses from infecting cells by neutralizing them are associated with vaccine effectiveness. A new study indicates that c ellular response (T-cell proliferation and whole blood Interferon-Gamma Release assays) might provide a better measure. The study tested 7 vaccinated and 7 non-vaccinated ICU patients during original Omicron wave and compared them to 8 healthy vaccinated volunteers. Upon ICU admission, vaccinated patients presented high anti-Spike IgG titers that were significantly higher than non-vaccinated patients (Figure A ). In contrast, T-cell proliferation in response to spike antigen was absent (Figure B). In accordance, in response to SARS-CoV-2 antigens whole blood Interferon-Gamma Release Assay (IGRA) was found to be very low in vaccinated patients whereas they presented with strong response to mitogen (PHA) which illustrated appropriate functi...