You say "caused", but it seems that the research points to a weak correlation at best. Given a potential incidence of 1 in 50,000 in a disease/condition which is hard to diagnose, I think this rather points out again how extraordinary sensitive the whole vaccination vigilance system is.
Given the increased focus on the Covid vaccines, correlations as these would have already been found.
The estimated rate in children and adolescents was 1 in 18,400, which is still a very relevant number because it's substantially higher than that group's risk of similarly life-altering complications from SARS-CoV-2 infection.
My latest information on the impact of long covid in children says that 1 in 25 are affected with serious health problems for more than 3 months after infection. This is from a Swiss study of school children.
It thought that narcolepsy much as fatigue is something that is easily missed when showing weakly. Tired kid?
Given the increased focus on the Covid vaccines, correlations as these would have already been found.