Virus Crochet Shawl Pattern may be a strange name for a project. In fact, this is one of the most popular crochet shawl patterns among crocheters. If you are wondering where the ‘virus crochet shawl’ name comes from, it is due to the ‘viral’ nature of the pattern. It grows quickly as a virus with each round. There are many variations of this popular pattern. Although they all have the same basic structure in their foundation.