I started by searching like this:
site:.mil "fear appeal"
...and started reading.
https://dde.carlisle.army.mil/documents/courses_13/Readings/2200_gerras.pdf
Appeal to Fear. This involves an implicit or explicit threat of harm to advance your position. A fear appeal is effective because it psychologically impedes the listener from acknowledging a missing premise that, if acknowledged, would be seen to be false or at least questionable.
Fear Appeal during Viet Nam war
The aim of the fear appeal was to convince the enemy that he faced an overwhelming danger of being killed if he remained with the communists. Message themes included "death lurks everywhere," "born in the north to die in the south," and "no shelters are safe from the bombs of the B-52."
Fear appeal in the UK:
https://news.sky.com/story/coronavirus-how-the-pms-slogans-have-changed-12040037
First we were told to "stay home". Then we were warned to "stay alert". Now, Britons are being advised to remember "hands, face, space"....'Stay home, protect the NHS, save lives'
Fear appeal In Canada:
scary hospital scenes "Stay at home: Save Lives"
Breaking down fear appeal as it applies to current times:
What is the position they want to advance?
What is the threatened harm?
What premise is missing?
In theory this could work but not in reality.
Of course the obvious weakness is lack of control over media organizations to support the message. The legacy media controls the loudest voice and anything that is counter to their preferred message gets propagandized against and ignored/destroyed.
Meanwhile their messaging of fear is pumped out unceasingly and virtually unchallenged. It is not a fair fight.