I'm usually not a fan of books where you really have almost two separate stories told in alternating chapters that barely or never intersect but it wasn't as much of a problem for me in this book as it has sometimes been. I thought both stories were engaging and entertaining. I do have several issues though:
I've just read a few books on the black plague in the 1300s and it's clear that the author did some research, unfortunately, it also feels like she felt a need to mention all the standbys. The characters see Princess Joan on her ill fated trip to join her groom, the physician hears rumors of plague ships from Genoa, Jews are accused of poisoning the wells, etc.
As with many historical fiction novels where a central character is a physician, Alejandro is well ahead of his time. He virtually ignores the teachings of Galen (who is really only given passing mention even though his theories were the predominant theories for centuries, including the 14th), he figures out the importance of hand washing and cleaning wounds, he talks about contagion theory which wouldn't be developed until many years later, and eventually even figured out the (now somewhat disputed) connection between rats and the plague. It's more than a little annoying. If you're going to write historical fiction, fine, but don't make your character the only one to figure out things that won't be discovered until decades or centuries later.
I'm not a scholar of Judaism, but I'm pretty sure that there are some very strong laws about autopsies. Granted, I think those are mostly followed by the most orthodox branches of the religion today, but I imagine they were still pretty strong taboos among Jewish people generally in the 1300s. So I found it very distracting that Alejandro doesn't have much compunction about slicing people open (post death, of course). Sure, now
we realize how important that is, but it wasn't generally accepted medical theory back then, and there was a very strong belief that doing so would be defying God's laws (whether God was the Christian or Jewish god). What qualms Alejandro has seem to be more about breaking civil law than relgious law.
As for Janie's world, I think exploring a post-antibiotic world is certainly an interesting idea, but I think Benson went way overboard. Maybe if I had a better idea of what the Outbreaks were like, the symptoms, how they spread, etc. I would disagree, but I have a hard time believing that post-antibiotics people will be shot on sight or detained indefinitely for being sick. Even before people knew what caused AIDS governments weren't going around killing anyone with symptoms (though I believe some governments did enforce lifelong isolation).
I also thought Benson sort of brushed off Janie's privacy concerns. She's afraid of the body print and afraid of how that information might be used, but when a small lesion that might, maybe, someday become cancer she seems far more willing to go along with the whole thing.
As I understand it, those who can afford it can have whole body scans done today (much
less invasively than the kind that Benson portrays). The problem is that while occasionally they do pick up problems that might be missed, it's far more often that a scan will reveal several small but ultimately meaningless things that do nothing but cause huge amounts of fear and worry.
I also think Benson didn't take it far enough. She didn't really explore the ramifications of forced body scans and forced revelation of the condition of one's body. Now there are some genetic tests available to determine if someone is likely to develop certain diseases, e.g., Parkinson's. As of right now taking that test and learning the results is entirely up to the individual. What happens when it is now the decision of the state? What if you no longer have a choice to know that you carry a gene for something that will very likely ultimately lead to your slow deterioration of your mind or body?
If detail on such a level is possible, would we start seeing a new form of eugenics? Would people be pressured not to have kids if the combination of genes from the mother and father might result in the child developing a serious chronic or ultimately fatal illness? Would women be pressured to abort if the fetus is less than perfect?