Covid-19 cases across the world have surged over the Christmas holiday period, with New Zealand’s cases more than doubling in the two days since Friday. On Sunday, the country reported 126 new infections in the community with 45 people hospitalised, eight in intensive care.In neighbouring Australia, the country’s most populous state reported a record number of new cases on Sunday and a sharp jump in hospitalisation while thousands of people were isolating at home after contracting the virus or…