On Feb. 8, 2021, Tonix Pharmaceuticals announced it had received the written response from the FDA to a Type B pre-investigational new drug (IND) meeting package describing its technology and plans to develop a diagnostic skin test, TNX-2100 (SARS-CoV-2 epitope peptide mixtures for intradermal administration), to measure the delayed-type hypersensitivity (DTH) reaction to SARS-CoV-2 (CoV-2), the virus that causes COVID-19.