Tossing out the "Military Whistleblower" is to get attention. Any and everyone in the military knows from the first week of boot camp you have a right to write your Congresscritter. Problem here is invoking such a right without the window dressing )Whistleblower" gets little attention.
And it doesn't matter what the Whistleblower act states. She needs to start looking for a new job. No reprisal for reporting this to Congress is so easy to get around in the government. Your conduct and performance is going under a microscope within the bounds of what is expected and you're going to lose.
Hope it's worth it to her. It's not going to stop the vaccinations.
In her place, I would be more concerned with reporting to the CoC that there is a possible bad batch of vaccine given the circumstances of the alleged causes of death. That is the immediate concern that should be looked at.
“When bad men combine, the good must associate; else they will fall, one by one, an unpitied sacrifice in a contemptible struggle.” Edumnd Burke