Although the frequency of IL-2 monofunctional CD4+ T cells was significantly lower to BA.1 peptides (p < 0.001), this represented only a 19.7% decrease from ancestral SARS-CoV-2, suggesting that infection with Omicron BA.1 in transplant patients also expands homotypic and heterotypic T-cell responses, in particular, CD4+ T cells, but also CD8+ T cells, to similarly high frequencies. Here, CD4 is linked to infection.