An article in last Friday’s issue of Science got predictably hysterical coverage in the media. Written by Ezekiel Emanuel and Alan Wertheimer, a pair of "bioethicists," the article addresses the important issue of vaccine rationing in the case of an avian flu pandemic. If there’s not enough vaccine to go around — a virtual certainty — then who should be first in line to get jabbed?
The authors invoke what they call a "life-cycle principle," which is based on the idea that "each person should have an opportunity to live through all the stages of life …. to be a child, a young adult, and to then develop a career and family, and to grow old — and to enjoy a wide range of the opportunities during each stage." They then balance this with an "investment refinement," which "gives priority to people between early adolescence and middle age on the basis of the amount the person invested in his or her life balanced by the amount left to live." And finally they assert a "public order principle," which focuses on the need to ensure the proper functioning of the social infrastructure — police, hospitals, etc.
Bottom line? Vaccinate health workers first, then move on immediately to folks between 13 and 40. Or, as one typical newspaper headline puts it, "Should pandemic vaccine skip kids, elderly?"
But it is one thing to invoke ethical principles in such a scenario, and quite another to formulate a plan of action based on them. The first step is entirely abstract, while the second requires a sophisticated understanding of the science behind vaccination and pandemic flu. The authors seem to be working under the assumption that a vaccine is like medicine — it helps only the person to whom it is administered.
But this is far from the case. Consider the case of elderly nursing home residents. Studies have shown that the best way to protect the elderly from the flu is not direct vaccination. In terms of alleviating symptoms, vaccinating the elderly is strikingly ineffective — some estimates suggest that only a third of flu cases are prevented using this tactic. But vaccinate nursing home workers and those statistics are markedly improved.
In other words, if the ultimate goal of bioethicists is to have the greatest number of 13-40-year-olds live long and productive lives (a goal I’ll leave unchallenged for the purpose of this discussion, though it strikes me as ethically challenged), that doesn’t necessarily mean the most effective way to do that is to immunize that group specifically. In fact, the footnotes in their own paper suggest a rather different approach. Near the end, they claim that a recent paper by M. Elizabeth Halloran and Ira M. Longini confirm that their own vaccination priorities would "save the most lives." This is preposterous. Longini’s research does not focus on 13-40-year-olds, but on schoolchildren, aged 5-18, a rather different approach. His conclusion is that a "combination of vaccinating schoolchildren and older adults would be most effective for reducing influenza deaths. Results from influenza simulations that we have conducted indicate that vaccinating just 20% of the schoolchildren would do more in reducing overall mortality in adults over 65 years old than vaccinating 90% of the adults over 65 years of age."
This is important information that anyone responsible for public policy (or ethical decisions) has to take into account. But it is only barely seeping into the consciousness of the public — or, for that matter, of "bioethicists." There are reasons for this, which I hope I’ll be able to get into in a later post.