Job Recruitment Website - Immigration policy - In the years after the First World War, there was a great increase in immunization.

In the years after the First World War, there was a great increase in immunization.

In the years after World War I, there was a large-scale immigration tide.

Followed by the past participle as an adverbial.

Following World War I means following World War I ~ ~ ~ instead of saying that World War I broke out after the increase of immigrants.