Having a positive mindset does wonders, especially for stress. Yes the world isn't great right now and we're probably gona be in for a rougher ride but in this case it's mind over matter. It's fine if you don't want to interact/socialize with people but get some fresh air and sun. Apart from stress, a lot of illnesses stem from vitamin d deficiency. Actually human interaction can also alleviate stress and increase mental health, a simple hug is a good example.
From my understanding of what a virus is, is that it is information encoded in a protein capsule. We all have it and it is triggered when a foreign body enters our system, so our bodies activates the "virus" aka information from our DNA to attack the foreign body thus making us expell it through runny noses, coughing, sweating etc purging what our body doesn't want or need.