You can sum expected utility of doing your your activity A K times like so:
Calculate expected utility of doing activity A K times with K chosen in such way such that p is approximately 0.5
Then your calculation becomes: E = KU-C/2. Is this E still positive?
Another objection is that you assume that C is fixed, but it is actually a function of utilities of all the activities Ai with positive utility which you will be unable to do if infected.
You can sum expected utility of doing your your activity A K times like so:
Calculate expected utility of doing activity A K times with K chosen in such way such that p is approximately 0.5
Then your calculation becomes: E = KU-C/2. Is this E still positive?
Another objection is that you assume that C is fixed, but it is actually a function of utilities of all the activities Ai with positive utility which you will be unable to do if infected.