Does this conflict arise in choices about priorities for vaccine development? Perhaps the closest parallel would be a choice between potential vaccines for two life-threatening diseases, A and B, where A has a slightly greater burden of disease than B because there is a slightly greater incidence of A than B. If A is given priority over B, and a successful vaccine to prevent A is developed and employed, but no effort is supported to develop a vaccine for B, then people who develop life-threatening disease B may complain that they did not have a fair chance to survive through the development of a vaccine to prevent their disease.
There are at least three considerations that mitigate this ethical conflict in the context of vaccine development as compared with organ transplantation. The first is that vaccine development need not be an all-or-nothing choice, as in the case of recipient selection for scarce heart transplants, but a matter of the relative priority for funding to be given to the development of vaccines for different diseases. If disease A is given a higher priority for vaccine development than disease B because of A’s greater burden of disease, this need not and typically does not mean that no resources go to the development of a vaccine for B, but rather that a greater effort with more resources will go to A than to B. Suppose the effort to develop the vaccine for A succeeds, while the effort for B fails, at least in part because of the lesser effort and resources that went to B. Individuals who contract B cannot complain that the small difference in expected benefits from a vaccine for A instead of for B was an unfair basis for selecting who will live—those who would have contracted A—and who will die—those who contract B. The small difference in expected benefits from a vaccine for A as opposed to B resulted only in a comparable small difference in the effort and resources devoted to vaccine development for A and B. Even if that small difference results in the earlier development of a vaccine for A than for B, it is not obvious that that is unfair to those who contract B and even die from it.
The second consideration that mitigates some of the conflict between fair chances and best outcomes in the case of vaccine development is that the prioritization of different potential vaccines is not a choice between identified patients, as in organ transplantation, but a choice between potential vaccines for different diseases made for the most part before we know which individuals will contract the different diseases. In that respect, the prioritization of disease A over B is not a life-and-death choice between identified patients who have diseases A or B because it is made before we know who will get A or B, even if the choice will eventually have life-and-death consequences for identified individuals (in fact, with the disease for which a successful vaccine is developed and deployed, the individuals who would have died from that disease without the vaccine will typically never be identified or known). It could be argued that before one knows whether one will get disease A or B, one would give greater priority to preventing whichever has the greater disease burden. Thus, it is less clear that the vaccine development choice in favor of the disease with the greatest health burdens and potential benefits is unfair to those who contract the lower priority disease for which a vaccine was not developed, than is the choice of transplant recipients in our earlier example.