What we see is a vaccine brand that went wrong. If exposed to the actual virus many months later an immune over reaction can happen.
It happened many times with human trials on smaller scale, on different type of virus vaccine trials
Recognise the spread patterns.
It was army and children at the same time worldwide with the spanish flu, who got flu shots
Now it is old people, and people with underlying conditions worldwide who got flu shots
Not a normal viral patern geografically and age wise
If it was a stronger virus also many kids should be affected, like the normal flu pattern. Kids have low immune systems.
Logical thinking and Occam Razor