No lasting impact, but it may take influenza a few years to return to previous levels. In general biological systems always run at maximum [carrying] capacity.

No lasting impact, but it may take influenza a few years to return to previous levels. In general biological systems always run at maximum [carrying] capacity. If something blocks them it might take they a while to return to maximum, but they always do so. Like imagine a fire almost, but not completely, put out. It might take a little time to engulf things again, but it will eventually do so. (Unless of course the environment is no longer hospitable.)