SFKEELDKYFKNHTSP is a truncated peptide derived from the P4 peptide of the S2 subunit of the S protein of SARS-CoV-2 which has the the amino acid sequence DPLQPELDSFKEELDKYFKNHTSPDVDLGDIS, corresponding to residues 1139-1170. The P4 peptide is located in the linker region between heptad repeat 1 (HR1) and heptad repeat 2 (HR2) and is highly conserved among SARS-CoV, BatCoV RaTG13, SARS-CoV-2 and recent SARS-CoV-2 variants. Antibodies targeting the peptide SFKEELDKYFKNHTSP can neutralize both SARS-CoV-2 and SARS-CoV by preventing fusion between the virus and the cell membrane.