Researcher finds 'stunning' rate of COVID among deer. Here's what it means for humans

white-tailed deer
A young white tail deer looks up from a hillside, Wednesday, Dec. 22, 2021, in Marple Township, Pa. (AP Photo/Matt Slocum)

Between October and December of last year, researchers swabbed the noses of 93 dead deer from across Pennsylvania. Nearly a fifth of the animals tested positive for COVID.

This is one result from a new pair of soon-to-be-published studies with the latest evidence for COVID spillover from humans into wild white-tailed deer where the virus picked up a raft of new mutations. In addition, in one case, COVID most likely later spilled back from the deer into a human. That’s a first.

These new findings — which follow an earlier study about COVID in the white-tailed deer population — are raising renewed concerns over the unpredictability of spillover events and the potential risks posed to humans. Here are a few questions being asked about the deer spillovers.