NICOSIA, Dec 31 (Reuters) - Cyprus registered a record high 5,048 new cases of COVID-19 on Friday in a surge largely blamed on the Omicron variant spreading throughout Europe. The island reported 3,851 new cases on Thursday, up from fewer than 2,000 cases at the start of the week. Authorities this week extended a mandate for working from home and compelling everyone, including vaccinated persons, to test for COVID-19 at least once a week. Since the COVID-19 outbreak in March 2020, there have been 166,827 cases reported and 638 deaths. Cyprus reported its first case of the Omicron variant on Dec. 10. Health experts believe Omicron is more contagious than previous variants, but two studies in the last week suggest those affected are less likely to require hospital treatment. read more The number of people on the island who have received both doses of a COVID-19 vaccine has exceeded 80 percent. A booster-jab programme began in September.