In my last post I characterized how overdoses from the surging opioid epidemic have become the fastest-growing cause of mortality among organ donors. In this update, I raise one potential consequence with ethical and policy implications: so-called donor-derived infections. To be clear, I focus primarily on organ recipients as deaths from drug overdose, and drug addiction more broadly, should be prevented regardless of any implications for transplantation. With this in mind, consider how the population of injection drug users shoulders a heavy burden of HIV, hepatitis B (HBV) and hepatitis C (HCV) (Table 1). First I will focus on screening guidelines, and then will move on to transplantation of organs known to carry an infection.
Screening guidelines can help reduce the incidence of donor-derived infections, but the lab tests recommended in any policy must balance two potential concerns. First, lab tests have a rate of false negative results. Transplants of these organs will accidentally increase donor-derived infections. The policy question, then, is whether or not transplanting organs donated by individuals with higher risk of recent disease exposure will expose an unacceptable proportion of recipients to infection. This unintentional harm could undermine a duty of non-maleficence to organ recipients. Further complicating a potential screening policy is that the basic lab tests for HIV, HBV, and HCV detect the presence of human antibodies, which work well among a low-risk population, but antibodies might not appear in the blood until weeks after infection (Table 2).Recent infections are better detected by nucleic acid amplification (NAT) testing.To mitigate risk of infection,then, transplant screening policies should require a heightened level of surveillance among donors with a history of illicit drug use. Continue reading →
The recent arrival of Ebola in the United States has captured the attention of both the public and the media for many reasons. One key reason is that Ebola is making many people realize for the first time that serious diseases which were formerly confined largely to developing countries have the potential to spread more widely across the globe. But Ebola is not the first infectious disease to spread in this way, and it’s valuable for Americans to realize that many diseases which are often viewed as existing only in developing countries are already present in the developed world, due to a complex set of factors including migration and climate change.
Specifically, serious diseases transmitted by insects like chikungunya, dengue fever, and Chagas disease are already here in the United States. I blogged here in August about DARPA’s prize to predict the spread of chikungunya, and the CDC’s estimates suggest that the disease may be finding a foothold in this country, with 11 locally-transmitted cases in addition to the more than 1500 travel-associated cases confirmed so far in 2014. Compared to an average of just 28 cases per year since 2006, the spread is concerning. Scientists also contend that dengue fever, a disease with similarly debilitating symptoms, is now endemic to Florida.
The case of Chagas is even more dramatic. Categorized by the CDC as a “neglected parasitic infection,” it is estimated that 300,000 infected people live in the United States. That’s ten times as many people as are diagnosed with ALS, a disease which has made much more of a mark on the public consciousness. Chagas’ impact (both human and economic) on the United States’ health system is and will continue to be extremely costly, with one study estimating the economic cost to the United States at roughly $900 million annually. Some of these costs are indirect — for instance, donated blood must now be screened for the presence of the parasite, to prevent its transmission. But most are direct. Over the long term, Chagas can cause severe, even fatal damage to the heart and gastrointestinal tract. Continue reading →