Editorial Commentary: Exceptions That Prove the Rule

David K. Henderson 0 0 Hospital Epidemiology Service and the Office of the Deputy Director for Clinical Care, Clinical Center, National Institutes of Health , Bethesda, Maryland EDITORIAL COMMENTARY - The exception that proves the rule This often-misunderstood English language idiom, at least in its loose rhetorical sense [1], is highly applicable to the transmission from providers infected with blood-borne pathogens to their patients (ie, the rarity of these events helps characterize and define the miniscule risk for these transmissions in the practice of modern medicine). Decades of experience have taught us that providers infected with blood-borne pathogens pose a small but nonetheless detectable risk to their patients, specifically when the provider is performing what have now been termed exposureprone invasive procedures on patients. Because of this small but clearly detectable risk, particularly for providers infected with the hepatitis B virus (HBV), the optimal management of healthcare providers infected with blood-borne pathogens has been controversial. The risk for provider-to-patient transmission is so small that it cannot be measured with precision, and the small numbers of instances of provider-to-patient transmission of HBV, in essence, provide evidence for the rule that such transmissions are remarkably rare. In 1991, in great measure in response to the occurrence of 6 cases of iatrogenic human immunodeficiency virus (HIV) transmission in the practice of a Florida dentist [24], the Centers for Disease Control and Prevention (CDC) issued guidelines recommending that healthcare workers who are infected with HIV or HBV and who have circulating hepatitis B e antigen (HBeAg) and who desire to perform such exposure-prone procedures can continue to perform such procedures only after first notifying the patient of the healthcare providers infection as well as after consulting an expert review panel to determine, under what circumstances, if any, they may continue to perform these procedures [5]. These guidelines remained as the practice standard in the United States until 2010 when the Society for Healthcare Epidemiology of America (SHEA) published new recommendations about the management of providers infected with blood-borne pathogens [6]. Subsequently, in 2012, the CDC published Updated CDC Recommendations for the Management of Hepatitis B VirusInfected Health Care Providers and Students [7]. These new, sentient guidelines represented a substantial departure from the prior US Public Health Service guideline published in 1991 [5] and now provide a clear approach to this problem for hospital, health departments, and occupational medicine providers. In this issue of Clinical Infectious Diseases, Enfield and coworkers report another well-documented instance of provider-to-patient transmission of HBVdocumenting at least 2 instances of transmission of HBV to the patients of an HBV-infected orthopedic surgeon who also had a high circulating viral burden [8]. In 2012, such cases are clearly exceptional in the true sense of the word. Transmission of blood-borne pathogens from providers to patients has become exceedingly rare. The development and wide implementation of hepatitis B immunization, both specifically for healthcare workers as well as for the population at large, has had a profound influence on the prevalence of this blood-borne infection in the United States. Nonetheless, the influx of practitioners into the US healthcare delivery milieu from areas in the world where the prevalence of HBV infection is high (and, therefore, the likelihood of transmission from mothers to newborns is high, producing a significant population of individuals who have high circulating viral burdens and little evidence of liver disease) has provided an influx of US healthcare providers who are chronically HBV infected and who have high circulating HBV viral burdens. Whereas such practitioners do present a risk for transmission to patients during the conduct of exposure-prone procedures, the development of highly effective antiviral therapy for this infection provides a mechanism for reducing such practitioners circulating viral burdens, thereby minimizing the risk for transmission. Fortunately, the prospects for successful treatment of all 3 of the major blood-borne pathogens have increased dramatically over the past 2 decades. Several points about the instances of transmission of HBV described by Enfield and colleagues are worthy of additional emphasis. First, the provider who transmitted these infections was unaware of his infection status. In the year 2012, in my view, all providers who conduct these types of procedures on patients have an obligation to be aware of their infection status with respect to all 3 of the major blood-borne pathogens hepatitis B, hepatitis C, and HIVand, if they find themselves to be carriers of one of these pathogens, they should seek the counsel of the expert review panel in their institutions or health department jurisdictions. This process is detailed in the 2010 SHEA guideline [6] as well as in the 2012 CDC guideline [7]. A second point worthy of emphasis is the fact that the infected provider in the Enfield et al study had failed to respond to 2 complete courses of hepatitis B immunization. This finding should be an immediate red flag and should raise the possibility of chronic HBV infection in the provider in the minds of the staff administering the vaccine. This finding should be communicated to the director of the occupational medicine program. In every instance this finding should require follow-up on the part of the occupational medicine staff to make certain that the provider is not a chronic HBV carrier. A third point worthy of emphasis is that the provider in question had immigrated to the United States from an area in which HBV infection is endemic. This finding, particularly in the setting in which the provider previously has failed to respond to 2 full courses of hepatitis B immunization, should underscore the need for further follow-up. Despite the fact that this surgeon was performing exposure-prone procedures, had a very high circulating HBV viral burden (>106/mL), and was found to be HBeAg positive (both of the latter circumstances would, if known in advance, likely have precluded his conduct of exposure prone procedures), definite transmissions occurred to only 2 of the patients who received follow-up. As many as 6 additional patients may have acquired infection, but from the current article, we have no way to know which, if any, of these patients may have acquired their infections from the surgeon. According to Enfield et al, the surgeons peers and supervisors thought he had excellent surgical technique. The low rate of transmission observed in this setting may relate to a number of factors, among them that the surgeon had excellent technique and routinely double-gloved in his surgical practice, and that, even in th (...truncated)