Protective heterologous T cell immunity in COVID-19 induced by MMR and Tdap vaccine antigens

High correlation was observed between T cell responses to SARS-CoV-2 and MMR and Tdap vaccine proteins in infected and uninfected individuals; the overlapping T cell population contained an effector memory T cell subset previously implicated in protective anti-viral immunity and their activation required APC-derived IL-15, known to sensitize T cells to activation. We were able to detect cross-reactive TCR repertoire in antigen experienced T cells recognizing SARS-CoV-2, MMR and Tdap epitopes using clonotyping and scRNA-seq. Indices of disease severity were reduced in MMR or Tdap vaccinated individuals by 32-38% and 20-23% respectively, among 73.582 COVID-19 positive patients. Total of 12 human samples, T cell samples from 3 controls and 3 patients were analyzed for the study. 3 Control and 3 patient samples were treated with SARS-CoV-2 antigens and 3 samples from patients were treated with MMR and 3 samples were treated with Tdap antigens. Submitter states "The sequencing was performed by an outside company; we are attempting to locate the fastq files"