CD8A and infection: The increase in vaccine-mediated cytotoxic memory T cells at lymph nodes [mCTLLvac] upon transformation of [CD8+To], natural death of [mCTLLvac], increase in [mCTLLvac] with migration of vaccine-mediated cytotoxic memory T cells at sites of vaccine administration [mCTLrvac] and vaccine-mediated cytotoxic memory T cells at sites of infection [mCTLRvac], and decrease in [mCTLLvac] upon migration of [mCTLLvac] toward sites of vaccine administration and infection.