I dont really know much about this but I know youre probably right in the context of the world wars.
Was it Spanish flu? IDK, but poor nutrition, hygiene, and close proximity in the trenches was a huge factor.
In a present day war, it would probably be different? Still some "dug in" defences but far more ranged, airborne, and remotely controlled armaments.
Its probably just anxiety but since the last one I haven't been able to shake the feeling that another is inevitable.