After yesterday's public health note on the anniversary of the development of the polio vaccine, we're brought back to the present day reality by the wide and inadvertent distribution of the H2N2 "Asian flu" strain which killed millions worldwide in 1957 and 1958.
Fifty years ago today came the official announcement that the Salk vaccine against polio was safe and effective. It was one of the great accomplishments of the 20th century.
As a school kid in New York, I recall standing in the long lines to take part in the trial to test the vaccine.
Even earlier I recall my friend Sally Sargeant down the street in Kansas who was already wearing heavy leg braces from the disease's effects. Even at that young age, I knew what an "iron lung" was.
And when the vaccine was put into general use, we received it from our family pediatrician in New Jersey, Dr. George Salmon, a guy we four kids liked and our parents respected. Dr. Salmon walked with a pronounced limp, the result of the same disease and the reason for his entering medicine.
Truly monumental. And a reminder of the personal in great science, public health and medicine.
We've been interviewing Paul DiGiovanni, MD about his dual roles, physician and county legislator.
In our last post, we discussed Medicaid. (The first part is here.) In this one, we explore public health and some operational issues.
With the flu vaccine shortage, most of the focus on "high risk" populations, the elderly and other vulnerable people. We may be missing the point.
In systems dynamics terms, focusing on the high risk population is focusing on a downstream stock (of people in this instance). Should we instead be focusing on transmission, which in SD terms, is a flow?
Listen to this NPR story on the same subject. In particular, listen to what happened in Japan when they focused flu vaccine on school kids. The incidence of flu went down among the elderly.
The attached diagram is of a generalized epidemic model. It's not specific to the case under discussion and doesn't deal with a range of factors such as deaths. But note the place of factors that influence the flow of people from one stock (the boxes) or status to another. Obviously the presence of vaccine slows the flow from susceptibles to infected, non-symptomatic. But so do the average contacts per day and the probabilty of infectious contact.
The purchase requires approval by the Food and Drug Administration because the
vaccines have not been licensed for sale in the United States. And there appear to be some misgivings. The article states:
Anyone receiving the specially imported vaccine "will be required to sign a
consent form which indicates that they understand all of those ramifications,"
acting FDA Commissioner Lester Crawford said.
But it doesn't say what "those ramifications are. We can imagine, can't we?
Systems Dynamics is the discipline of taking feedbacks into account when evaluating organizations and systems (think vicious and virtuous cycles). Feedbacks, especially if delayed, have powerful but too often hidden effects on systems and decision making. Part of the visual representation of SD models is the use of "stocks" (think bathtubs) and "flows" (think water flowing in and out). Flows between stocks are controlled either by decisions or feedbacks within the system model. The visual representation aids considerably in reducing ambiguities and misunderstandings and even occasionally helps ferret out hidden agendas.
We've found System Dynamics to be a very powerful method for thinking about healthcare systems and problems, but have generally made it a habit of hiding our approach. (As one prospective client told us once as they were turning us down after a long marketing effort: "this stuff is just too weird for us.") Instead, we've translated the results and simplified our description of the methods and it's generally worked out OK. However, this has meant that the clients have lost a lot of the potential power of the approach and even when they've embraced our work, they haven't prepared themselves for the next problem. It's a bit like the "wonks" and "hacks" divide that we've talked about before, understandable, but frustrating. We've found clients who make the effort and jump into SD benefit from doing so and it's both refreshing and promising when we see other organizations taking it on.
So it was a delight to get a note from Jack Homer, one of the leading practitioners of System Dynamics about the work he and colleagues are doing with CDC (Centers for Disease Control and Prevention). CDC is in the process of redefining its mission and reorganizing itself accordingly, an effort known as the Futures Initiative. SD is contributing significantly to this effort. Here's my paraphrase of part of Jack's note:
Earlier this month, the CDC aired a satellite broadcast to update colleagues across the country on the progress of the Futures Initiative, with introductory remarks by Dr. Julie Gerberding, CDC Director. Featured prominently in Dr. Gerberding's remarks was a stock and flow structure with policy-driven flows (see below). This seemingly simple graphic shows how society's health system is organized, and is being used at the CDC to help articulate a new mandate for the agency in the area of health protection. Although far more remains to be done to incorporate systems thinking and systems-based policy analysis at the CDC (next frontier: feedback loops!), Jack & his colleagues believe this is an important step toward that end.
Kudos to Jack, his colleagues, Dr. Gerberding and the CDC!
Lancet has published a retraction by the majority of the authors of a key study of the relationship between the measles, mumps and rubella vaccine (MMR) and autism. Here's the statement issued by Lancet.
The original publication in 1998 suggested a relationship. The original study may have been compromised by a conflict of interest of the key researcher. That researcher failed to reveal that he was simultaneously working with attorneys preparing a case for the parents of autistic children.