Despite a large number of mutations, T cell responses against Omicron is similar to that against other variants, according to authors Jergovic et al. (JI, 2022).
The group from University of Arizona used Mabtech IRIS and FluoroSpot Flex: Human IFN-γ/TNF-α/IL-2/Granzyme B to assess T cell immunity in mRNA vaccine recipients. A slight decrease in IFN-γ/IL-2 double secretors was observed, but IFN-γ/GzB and IFN-γ single secretors remained intact when stimulated with Omicron peptides compared to the ancestral strain.
Interestingly, recipients of three doses mRNA vaccine had better T cell responses than recipients of two doses, supporting the view that three doses should be the recommended regimen.