Biology in All of its Complexity


In the wake of the recent debate about vaccines and whether we keep our children “too clean” (hand sanitizer, removing all dust and allergens) or not “clean enough” (5 second rule, dust once a week), I thought it might be helpful to share a recent Econ Talk that I listened to titled Velasquez-Manoff on Autoimmune Disease, Parasites, and Complexity.

I thought it did a wonderful job of illustrating the differences between microbes and parasites versus viruses. Moreover, Velasques-Manoff astutely recognizes the complexity of human biology and cites examples illustrating that complexity and how unpredictable it can be.

Here are the items I found the most interesting:

  • There is empirical evidence that children that are born and raised in environments with more microbes and parasites are not as likely to have certain auto-immune diseases and allergies.
  • Conversely, an individual that is raised in an environment with less microbes/parasites (suburbs) and then moves to a location (farm, for example) with more microbes/parasites will not benefit from the increase. In fact, their health may suffer as a result.
  • Individuals with auto-immune diseases that introduce parasites into their system have seen their symptoms fade or go away entirely. However, they have to deal with the affects of the parasite.
  • Microbes and parasites require (generally) that their host continues to live, whereas viruses do not require that a human lives since they are able to move from host to host. (Because of this difference, vaccines are absolutely necessary, whereas growing up amongst microbes and certain parasites may have actual benefits.)
  • There is evidence that the human immune system is calibrated during pregnancy. The environment that the mother is in during that pregnancy is instrumental in that calibration process.
  • Human biology is one of the most complex systems to ever be studied and is still not well understood. :-)