I had the moderna, sore arm and dehydrated the next morning. Soon as I drank a glass of water, felt better. I'll be pounding Gatorade before and after my second vaccine.
With any vaccination, if you do contract any disease, symptoms will be less serious since your body already has built some resistance to the immunization. From Les' call, I could hear some hoarseness and congestion. He says he only had the aches for yesterday evening and I didn't hear any coughing, which is a good sign. I had them for 1.5 days in March 2020. It was brutal.