Listen to your body. I never got the flu vaccine for many years since I never had a serious illness and knew how some years it provides little protection from whatever strains are prevalent. Then one year I was sick for 10 to 12 days where I had a low fever and was sick to my stomach for the whole time. I could do little around the house and there is no way I could have done any running. The corona virus symptoms are different and those with it could have mild, if any symptoms, or could end up in ICU.
Those who get sick with a virus or flu should listen to their bodies and do not attempt to do more training than they can safely and comfortable handle. Stick with easy runs at most and avoid long runs and speed workouts if feeling sick.
I signed up for no races this year yet as I am still trying to fully heal from a muscle strain from last fall. My plan has been to not sign up for any races until I know I am fully healed and until about a week out from the race so I have some idea that the weather will not be terrible. I ran in the 2018 Boston Marathon and other races with terrible weather so I don't need to do more. Now with the threat of race cancellations there is another reason to hold off on registering until the last minute.
The LA Marathon was still on for this weekend last I read.