To determine whether a difference in antibody to hepatitis B surface antigen (anti-HBs) response to a hepatitis B vaccine challenge dose existed among persons with a baseline anti-HBs level of 0 mIU/mL (group 1) and those with “non-zero” levels of 0.1–4.9 (group 2) and 5.0–9.9 (group 3) mIU/mL, according to the VITROS ECi anti-HBs assay.

Subanalysis of randomized clinical trial. Response was defined as a postchallenge anti-HBs level of at least 10 mIU/mL and 4-fold rise in anti-HBs level 2 weeks after a single challenge dose of 10 vs 20 µg Engerix-B. Baseline was defined as the anti-HBs level immediately before administration of the challenge dose.

Pediatric integrated healthcare system near Houston, Texas.

Three hundred nineteen US-born 16–19-year-olds who completed the hepatitis B vaccine series during the first year of life.

One hundred seventy-eight persons had zero (group 1) and 141 (114 group 2 and 27 group 3) had non-zero anti-HBs levels at baseline. Response to the challenge dose was significantly higher among those with non-zero vs zero anti-HBs levels, irrespective of challenge dosage; only 1 person with a non-zero anti-HBs level failed to respond to the challenge dose (group 3, 27/27 [100%] vs group 2, 113/114 [99%] vs group 1, 145/178 [82%]; P<.0001).

Among participants with residual anti-HBs levels less than 10 mIU/mL 16–19 years after primary hepatitis B vaccination during infancy, non-zero anti-HBs levels, with rare exception, indicated persistence of immune memory to HBsAg.

ClinicalTrials.gov Identifier: NCT01341275

Infect Control Hosp Epidemiol 2015;00(0):1–5

To determine effect of environmental exposure on the survival and infectivity of hepatitis C virus (HCV).

Three aliquots of chimpanzee plasma containing HCV and proven infectious HCV inoculum were dried and stored at room temperature, 1 aliquot for 16 hours, 1 for 4 days, and 1 for 7 days. A chimpanzee (CH247) was sequentially inoculated intravenously with each of these experimental inocula, beginning with the material stored for 7 days. Each inoculation was separated by at least 18 weeks of follow-up to monitor for infection. The concentration of HCV RNA was measured and quasi species were sequenced for each experimental inoculum and in serum samples from CH247.

Evidence of HCV infection developed in CH247 only after inoculation with the material stored for 16 hours. No infection occurred after inoculation with the material stored for 7 days or 4 days. Compared with the original infectious chimpanzee plasma, the concentration of HCV RNA was 1 log lower in all 3 experimental inocula. The same predominant sequences were found in similar proportions in the original chimpanzee plasma and in the experimental inocula, as well as in serum samples from CH247.

HCV in plasma can survive drying and environmental exposure to room temperature for at least 16 hours, which supports the results of recent epidemiologic investigations that implicated blood-contaminated inanimate surfaces, objects, and/or devices as reservoirs for patient-to-patient transmission of HCV. Healthcare professionals in all settings should review their aseptic techniques and infection control practices to ensure that they are being performed in a manner that prevents cross-contamination from such reservoirs.