I can, since I've done cost-benefit analysis and have everything written by Kip Viscusi, the leading economic expert on the value of life.
W. Kip Viscusi | Faculty | Law School | Vanderbilt University
There's no "right" way to do this, but the purpose is to provide just the kind of analysis that informs when the cost of saving a life is an order of magnitude above or below any reasonable estimate of a value of life - because environmental (and other risk analysis) regulation requires determining how much harm is acceptable - if you try to eliminate all risk you shut down the economy so you have to draw a line at some point. There's a huge literature addressing this issue.
One reason we accept the flu is we are already spending billions each year to combat it, think vaccinating 100 million people is a "freebie?" And because flues mutate on a regular basis, there's no "magic bullet" right now, though researchers are working on a universal vaccine - and because there are varieties of flues, it's almost impossible to stop it from spreading. The cost benefit is to spend up to the point where we mitigate the potential damage to some extent but accept that additional spending would only have a minimal impact.
"Multiple promising studies" is not the same as a definitive study(s) that would justify moving these drugs from their current use (which obviously has some value or it wouldn't be produced and sold, it's not ibuprofen). For one thing, sometimes using a treatment that's untested could turn out to make things worse, extrapolating from a SSS to a large population should be done carefully.
