This paper describes in part what is going on with Influenza A:

Article Influenza A: Understanding the Viral Life Cycle

and says,

"The influenza viral genome is made up of negative sense strands of RNA. In order for the genome to be transcribed, it first must be converted into a positive sense RNA to serve as a template for the production of viral RNAs.

Replication of the genome does not require a primer; instead, the viral RNA dependent RNA polymerase (RdRp) initiates RNA synthesis internally on viral RNA. This is possible, as the extreme 5’ and 3’ ends of the genome exhibit partial inverse complementarity and, hence, are able to base pair with one another to form various corkscrew configurations. It appears that a great number of di-nucleotide base pairs form, although the full mechanism of viral genome replication is still yet to be understood"