The sounds of silence: Public goods, externalities, and the value of infectious disease control programs.

Professionals who devote their careers to the control of communicable diseases, whether in the community or hospital setting, are assured an endless and varied series of challenges due to the dynamic nature of microbial populations, the mobility of human populations, and technological changes that facilitate the emergence, identification and quantification of emerging infectious disease threats. However, many practitioners working in hospital epidemiology or public health have experienced the following frustration: the incidence of an infectious process has been reduced or eliminated through application of a successful control program (eg, the introduction of vaccination or active surveillance for carriage of antimicrobial resistant pathogens). As the threat of the disease in question (whether measles or infection with health care-associated methicillin-resistant Staphylococcus aureus [MRSA]) declines, administrators or program participants question the necessity of the program, with subsequent erosion of resources and support. The opposite may occur: elimination of disease surveillance programs or case-finding efforts may result in an apparent decline in disease incidence, with a resultant pat on the back from administrators for a job well done. A number of examples of this phenomenon, drawn from recent newspaper headlines, come to mind. In Ontario, the legal requirement that cheeses be pasteurized (a health measure that has been successful in diminishing serious foodborne illness) has been criticized, even in the face of contradictory calls for ‘enhanced food safety’ following the province’s role in the recent pan-Canadian listeriosis outbreak (1,2). Resurgences have been identified in historically well-controlled vaccine-preventable diseases, including rubella, measles, mumps and pertussis in the face of increasing popular concern that the risks of vaccination do not outweigh the benefits when disease is uncommon (3). Perhaps the most poignant example of this phenomenon involves an Ontario health ministry spokesperson who, a year before severe acute respiratory syndrome (SARS) exposed gaps in that province’s public health capacity, justified cuts to the province’s public health laboratory as follows: “Do we want five people sitting around waiting for work to arrive? It would be highly unlikely that we would find a new organism in Ontario” (4). Complicating matters further, rapid growth of costs in health care (5) have resulted in demands that health programs, including those that target infectious disease prevention and control, justify their roles through demonstration of cost-neutrality, or even revenue generation. For example, a recent document produced by a working group of the Society for Hospital Epidemiology of America provided guidance to health care professionals on the construction of ‘business cases’ to justify hospital infection control budgets (6). To summarize this paradoxical state of affairs, control of infectious diseases requires active, ongoing intervention, but disease control successes manifest as the nonoccurrence of events (ie, silence). Maintenance of such silence requires active investment, but decision-makers and the public may be reluctant to invest when ‘nothing is happening’. Public health crises, including outbreaks and epidemics, result in a booster dose of interest, funding, and resources, but at a high cost (both health and monetary). We propose that the first step toward remedying this state of affairs lies in the recognition that maintenance of communicable disease control, in a jurisdiction or hospital, represents a type of ‘public good’. The economic framework that has previously been created to maintain other public goods (such as urban infrastructure or clean water) may have value if applied to communicable disease control.