I wonder if you have sources on this? I heard that this is a new variant that has a much longer incubation time. A longer time until symptoms appear means it will spread much quicker and wider (that was also the issue with Covid that had a incubation time of 5 - 8 days).

This variant may have longer incubation time but you are almost not infectious without symptoms. The more symptomatic you become, the more you spread. This is in contrast to COVID or some flus where you are most infectious in the incubation period.

Sure https://pmc.ncbi.nlm.nih.gov/articles/PMC4456362/ it outlines history and spread. incubation period is long but there is no asymptomatic transmission that is known.