reuse of insulin pens 1127
or HBcAb positive), none at either facility had HBV DNA levels equal to or greater than 500 copies/mL; therefore, fur- ther valid HBV genetic testing could not be performed. We identified 6 newHCVviremic case patients (5 and 1 at facilities A and B, respectively), in addition to 45 proximate patients (40 unique patients; 5 patients were positive for >1 genotype) with HCV viremia (41 and 4 at facilities A and B, respectively). Only 3 case patients (2 and 1 at facilities A and B, respectively) and 19 proximate patients (17 and 2 at facilities A and B, respectively) had samples available and sufficient HCV viral load for strain relatedness testing. At facility A, 23 strains that underwent molecular finger-
printing included 13 HCV genotype 1a (HCV-1a) patients: 10 previously HCV-infected, 1 newly found to be infected, and 2 epidemiologically unrelated patients; and 10 HCV genotype 1b (HCV-1b) infected patients: 7 previously HCV-infected, 1 newly found to be infected, and 2 epide- miologically unrelated patients. At facility B, 1 newly identified HCV genotype 2b (HCV-2b) patient was compared with sequences from 2 patients previously HCV-2b infected, as well as 2 epidemiologically unrelated HCV-2b strains and 1 epidemiologically unrelated HCV genotype 2a (HCV-2a) strain.
harboring HCV-1a and HCV-1b, including newly identified HCV-infected patients, were 10.6% to 22.6% for facility A patients, indicating nonrelatedness between facility A analyzed patient strains (Online Tables 3 and 4). Figures 1A and 1B present phylogenetic analyses displaying relationships between all sequences determined for facility A. All HCV sequences from each particular patient were very closely related to sequences obtained from that specific strain and significantly distant from all sequences from all other patients, indicating nonrelatedness for facility A. Median E1-E2 nucleotide dif- ferences for HCV-2b strains for facility B were 20.3% to 24.0%, indicating nonrelatedness between patient strains analyzed (Figure 2; Online Table 5).
discussion
In 1,155 tested patients, our findings suggest exposure to reused insulin pens did not result in documented viral trans- mission, in those patients among whom viral genetic analysis could be performed. No newly HIV-infected patients were identified among 1,137 patients tested (63.5% of 1,791 exposed). There were 63 newly identified patients with HBV infection among 1,126 patients tested (62.9% of 1,791 exposed). We do not know how long these patients may have been infected withHBV prior to this investigation. In addition, no patients had sufficient HBV viral load for genetic testing to be accurately performed, so unfortunately HBV transmission cannot be ruled out. Although 6 patients were newly diagnosed with HCV infection among 1,144 patients tested (63.9% of 1,791 exposed), only 3 patients had detectable viremia and sample available for genetic fingerprint analysis and no
Median E1-E2 nucleotide differences between all patients
linkages between HCV strains were found. Background seroprevalence differences could be attributed to patients undergoing laboratory testing outside of their primary VA facility, which would not have been captured in our facility seroprevalence calculations. Although, in aggregate, our find- ings do not provide evidence of viral transmission, we cannot definitively exclude the possibility that transmission of HBV or HCV occurred as a result of insulin pen reuse because samples on all case and proximate patients were unavailable for testing. Insulin pen reuse among multiple patients is not unique to
VA. US military researchers recently reported a similar inci- dent where insulin pens were reused on multiple patients, with new sterile needles after each injection. Similar to our results, they found newly diagnosed patients with HBV (3) or HCV (28) infection in more than 1,500 patients although no evi- dence of viral transmission using partial HCV genome sequencing of nonstructural 5b and core envelope 1 regions was found.22 From 2007 to 2013, several facilities reported insulin pen reuse on multiple patients.23–28 However, other than notifying patients and offering BBP testing, it does not appear that these facilities performed lookback investigations similar to our study. There are limitations of our investigation giving rise to
general recommendations for investigations such as this one. Earlier involvement of VA public health experts in the inves- tigation could have facilitated planning, procedures, and execution, ensuring uniform specimen protocols, doc- umentation that testing occurred, and sample being stored on all patients for confirmatory testing or molecular fingerprint- ing. Additionally, had insulin pens been available, BBP testing of pen cartridge contents could have been performed, com- plementing VA Office of the Inspector General assessments in the field.1 Since little evidence exists describing the significance of residual infectious bioburden when insulin pens are reused, having this equipment available for microbiologic analyses could have potentially better informed the decisions on the risk of these exposures. Patients were often difficult to find and notify and some were reluctant to undergo testing. Lengthy time intervals between occurrence and recognition of the problem led to large patient numbers being involved in the lookback, more than 25% of whom were deceased by the time the lookback was initiated and therefore could not be tested. Despite current BBP virus screening recommendations in the VA and from the US Preventive Services Task Force, prior BBP testing in our lookback populations even in patients already known to be positive for 1 BBP was incomplete.29,30 Absence of documented pre-exposure serologic testing in many indi- viduals made positive postexposure test results difficult to interpret, and adherence to BBP virus screening recommen- dations should be encouraged. Recent improvement in HIV and HCV serotesting rates has been noted in the VA and is encouraging news.31,32 Despite challenges, these investigations were important in determining BBP transmission risk resulting from insulin pen reuse. Our investigation found that insulin pen reuse did not
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