But Blanco was 74 -- not only did he survive, but he is the only survivor to have fully recovered.
In any case, I'm not suggesting a difference in mortality rate, but a possible difference in long-term effects among the survivors. (This is speculative, since there aren't enough cases for the difference to be statistically significant all by itself. But this adds to the other evidence that there were at least two, and maybe three, batches of anthrax involved.)
How's this for a hypothesis - there are maybe as many as 30 different batches. These were collected over the years. As the bacteria is grown and regrown over a long period of time you might get minor variations.
As far as the lab sourcing it would be concerned, it would all be the same thing.
The thieves would deal it as though it were identical. The final users wouldn't know the difference.
Some of it could have been sent in letters. Some of it handcarried to the site by saboteurs otherwise believed to be trustworthy employees.
And, the people buying the stuff may not have been aware that a number of the units they purchased had been sterilized.
Add in these quite reasonable conditions and the results would be dramatically variable.
I hesitate to put this thought out, but maybe this is due to the "subtle but possibly significant" differences between the FL and DC anthrax.
OTOH, maybe Ernesto Blanco's body simply has incredible healing power.