A<unk>  is a virus used when producing copies of a<unk>  dependent viral vector which does not have the ability to replicate on its own. The<unk>  is used to coinfect cells alongside the viral vector and provides the necessary enzymes for replication of the genome of the viral vector.
Helper virus
Marnavirus
Hantavirus
Hordeivirus
Ophiovirus
Varicosavirus
Benyvirus
Coronavirus