A RAND report in the NEJM estimates that pre-emptive mass smallpox vaccination would have a positive expected value of lives saved if the risk of a high-level attack exceeds 1%. It then recommends against mass vaccination.
That can’t possibly be right; what basis is there for thinking that the risk of a major attack is as low as 1%? (And why should we take an attack on 10 airports as the worst case?)
Moreover, the report makes three crucial mistakes:
First, it ignores all the non-mortality impacts of a smallpox attack against an unprotected population: not only temporary disruption and panic, but the substantial risk of sometimes heartbreaking disfigurement.
Second, it ignores the benefits of pre-emptive mass vaccination in case of a hoax attack.
Third, it ignores the deterrent effect of pre-emptive vaccination. Vaccination reduces not only the damage from an attack, but also the risk of an attack, since it means that a potential attacker has less to gain.
The study also seems to assume that the efficacy of post-attack contact tracing followed by isolation and vaccination is independent of the number of susceptibles in the population, which hardly seems plausible. (More fundamentally, it also assumes that the post-attack response will work as well in real life as it does on paper, which is hardly a conservative assumption with respect to the conclusion the study draws, but is not reflected in the sensitivity analysis.)
The estimated death toll from mass national vaccination is about 500: about 3 per million vaccinated. Are we really going to put the whole country at risk of a devastating attack in order to avoid 500 deaths? Now primum non nocere — first, do no harm — is a valuable maxim of medicine. But if doing no harm were all we expected of our health care system, I know where we could save a trillion and a half dollars a year. At some point, health care needs to do some good, even at some risk.
The report is a good illustration of why M.D.s and Ph.D.s in public health aren’t reliable substitutes for people with serious training in policy analysis. Any second-year MPP student should have been able to spot those issues.
The report isn’t a matter of merely academic interest, since the policy it recommends — vaccinating health-care workers only — is the one the Administration is actually pursuing. I hope this means that we have good intelligence showing that Iraq doesn’t have the capacity to mount a smallpox attack. If we’re about to be at war with Iraq, and if we’re not morally certain that Iraq has no such capacity, it’s time for some actual homeland defense.
UPDATE: ANOTHER GOOD REASON TO GO AHEAD
Duhhhhhhh…. I forgot that a substantial smallpox outbreak in the US would certainly spread to other countries, which is another major cost of not going ahead with vaccination now. Vaccinating our health care workers won’t do anything to protect the rest of the planet. Even ignoring humanitarian considerations — which we shouldn’t — explaining to everybody else in the world why we decided to put them at risk wouldn’t be any fun at all.
Glenn Reynolds, who made the international point before I did, tells me that the real reason for not going ahead with mass vaccination now is logistics. If that’s right, I know what Tom Ridge’s first job ought to be: breaking the logjam and getting this job done.
SECOND UPDATE
Phil Carter notes that the Pentagon is drawing up plans for the use of the military to enforce quarantines in case of a bio-warfare attack, and points out that in those circumstances procedural niceties would have to bow to public health. One more cost of not vaccinating now.