A transcription initiation process during which a nucleotide sequence between 10 and 20 nucleotides in size is cleaved from the 5' end of host mRNAs by a viral RNA-dependent polymerase. The capped leader sequence obtained is subsequently used to prime transcription on the viral genome, which ultimately leads to the synthesis of capped, translatable viral mRNAs.
cap snatching involved in viral mRNA transcription