The delay in approving Covid vaccines for children doesn’t imply any deep, dark secret about the vaccines or any risk they pose to children.
As with other medications, adult doses are usually too much for kids. Now, by the time many kids turn into teens, their height and weight is similar to adults. Thus adult doses present little concern with most junior high and high schoolers. With preteens, that’s simply not true.
Thus the medical research community has to determine the proper dosage for smaller bodies, basically, what’s the smallest dose that will provide effective protection for a child. Determining the ideal requires another round of clinical trials, and with the paperwork involved in approving children as research subjects, the trials take even longer than they do with adults. We all know how long it took for full approval of the Pfizer vaccine in adults.
There is no evidence of any push for an emergency use approval for a vaccine for children. At least not yet.
Don’t hold your breath for full approval for kids. That’s going to take awhile.