STOCKHOLM, Dec 21 (Reuters) - Sweden could see a more than 15,000 new COVID-19 cases per day in a worst-case scenario in mid-January, a record number, fresh projections from the Health Agency showed on Tuesday. In previous waves of the pandemic, daily infections have peaked at just over 11,000 cases. The new model projection factored in the spread of the more contagious Omicron variant, assuming it is 25% more contagious than the Delta variant and factored in varying degrees of protection offered by vaccines.