Why weren't Watson and crick awarded the Nobel prize immediately?

Watson and Crick were not awarded the Nobel Prize immediately because the Nobel Committee does not typically award prizes posthumously, and Watson and Crick's colleague, Rosalind Franklin, whose work was crucial to their discovery, had died in 1958. Additionally, at the time of the discovery of the DNA double helix structure, the Nobel Prize guidelines did not allow more than three people to share a single prize.