Travel restrictions are being reintroduced around the world after a new Covid-19 “variant of concern” was detected. The World Health Organisation says Omicron has a large number of mutations, and early evidence suggests an increased reinfection risk. It’s the first strain to be declared a variant of concern since the detection of Delta. Kathryn asks evolutionary virologist at the University of Otago Dr Jemma Geoghegan how concerned we should be about the outbreak of this new variant.