It’s not surprising that some deer have antibodies against COVID virus.
They probably fought off the infection with the one advantage most animals have — they make vitamin C from their blood sugar continuously.
These animals have an enzyme we humans don’t have. We depend on our diet to eat vitamin C rich foods raw or lightly cooked. Cooking or other processing will destroy the C.
Vitamin C is the only vitamin that is anti-viral and often acts as an antihistamine.
Two recent graduates of medical schools told me that their professors almost never gave them information about vitamins. Veterinarians know the C connection to animals. Other medical professions received variable amounts of nutrition information.