What we know about the Omicron variant

A new and potentially more transmissible coronavirus variant first identified in South Africa has prompted a fresh round of travel restrictions across the world and raised concern about what may be next in the pandemic.

The World Health Organization Friday designated the strain, now named Omicron, as a variant of concern and said multiple studies are underway as advisers continue to monitor the variant.

While scientists say there is reason to be concerned over the variant, they stress there is still a lot we don't know -- including whether the variant is indeed more contagious, whether it causes more severe disease or what its effects on vaccine efficacy may be.