New Covid-19 variants are likely to keep on emerging until the whole world is vaccinated against the virus, experts warn, saying that the sharing of vaccines is not just an altruistic act but a pragmatic one.

"Until the whole world is vaccinated, not just rich Western countries, I think we are going to remain in danger of new variants coming along and some of those could be more virulent than omicron," Dr. Andrew Freedman, a reader in infectious diseases at Cardiff University Medical School, told CNBC on Thursday.