High hepatitis C incidence in new injecting drug users: a policy failure?

OBJECTIVE: Evidence of ongoing hepatitis C (HCV) transmission among injecting drug users (IDUs) suggests a need for a better understanding of seroconversion characteristics among new IDUs and other vulnerable subgroups. This study aimed to determine incidence of HCV and associated risk factors among new IDUs in Sydney. METHODS: IDUs who had injected drugs in the past six months and who were unaware of their antibody HCV status or knew their serostatus to be negative were recruited through street-based outreach, methadone clinics and needle and syringe programs in south-western Sydney. Anti-HCV negative IDUs (n = 215) were enrolled and followed-up at 3-6 monthly intervals. New IDUs (n = 204) were defined as aged below 30 years or injecting for < or = 6 years at baseline. RESULTS: A total of 61 seroconversions were observed and incidence was 45.8 per 100 person years. Independent predictors of seroconversion were duration of injecting < 1 year (IRR = 3.10; 95% CI 1.47-6.54), female gender (IRR = 2.0; 95% CI 1.16-3.45), culturally and linguistically diverse background (CALDB) (IRR = 2.03; 95% CI 1.06-3.89) and intravenous cocaine use (IRR = 2.37; 95% CI 1.26-4.44). While new IDUs shared common risk factors, strong associations were observed between HCV seroconversion and sharing syringes, sharing other injecting equipment and backloading in CALDB new IDUs. CONCLUSION: Incidence of HCV infection among new IDUs in Sydney is unacceptably high. IMPLICATIONS: Extremely high rates of incident infection among newly initiated CALDB IDUs indicate an urgent need for enhanced policy and resource commitments to reduce the vulnerability of this group to HCV and other blood-borne infections.

Incidence and risk factors for hepatitis C seroconversion in injecting drug users in Australia.

AIMS: To determine the incidence of hepatitis C virus (HCV) infection and identify risk factors for seroconversion. DESIGN: Prospective cohort study. Participants were recruited through direct approaches, street-based outreach, methadone and sexual health clinics and needle and syringe programmes. SETTING: Urban, regional and rural settings in New South Wales, Australia. PARTICIPANTS: Injecting drug users (IDUs) (n = 584) were screened and tested for exposure to HCV. Between 1999 and 2002 antibody HCV negative IDUs (n = 368) were enrolled and followed-up every 3-6 months until seroconversion or study completion. MEASUREMENTS: Interviewer-administered baseline and follow-up questionnaires consisted of 131 items and included demographics, drug use and risk behaviour. Approximately 10 cc of whole blood was drawn at each visit. Specimens were stored at -70C and serology performed using one or two third-generation enzyme-linked immunosorbent assays and polymerase chain reaction testing. FINDINGS: Sixty-eight seroconversions were observed and incidence was 30.8 per 100 person-years, with incidence in IDUs injecting < 1 year, 133 per 100 person-years. Independent predictors of seroconversion were female gender, duration of injecting, injecting cocaine, shared use of filters and recruitment strategy. CONCLUSIONS: Women, new initiates and IDUs recruited via outreach appear to be at increased risk of infection. Results confirm the significance of cocaine injection as a risk factor and provide the first evidence outside North America of the link between shared use of drug preparation equipment and incident HCV infection. Prevention efforts should attempt to raise awareness of the risks associated with drug sharing and, in particular, the role of potentially contaminated syringes in HCV infection.

Meningococcal disease--probable transmission during an international flight.

Two cases of meningococcal disease were identified in passengers who travelled on the same international flight. Both cases were serogroup B with the same allelic profile. The public health action involved chemoprophylaxis for persons seated adjacent to, and in the rows in front and behind, each case. The most likely scenario is that transmission of N. meningitidis occurred on board a long distance flight, either from one case to the other or from an asymptomatic carrier to both cases. This scenario and the absence of reports of similar cases in the literature, indicate the risk to other passengers in this setting is low. This investigation reinforces the need for, and the distribution of, good national and international surveillance information to better inform public health decision making.

A novel hepatitis B vaccination regimen for adolescents: two doses 12 months apart.

BACKGROUND: Two- and three-dose hepatitis B vaccinations for adolescents are usually administered using dosing schedules of 6 months duration. This does not suit all circumstances. A 12-month schedule would be useful in schools and settings where only annual vaccination is the most practical option. AIM: To examine the efficacy of a 12-month dosing interval for two-dose hepatitis B vaccination of adolescents. SUBJECTS: Four hundred and fifty-eight healthy first-year high school (Year 7) students. VACCINATION REGIMEN: Engerix-B (GlaxoSmithKline Biologicals) 20 micro g: two doses, 12 months apart. SERUM COLLECTION: #1, same day as first vaccine dose given; #2, >1 month after second vaccine dose. RESULTS: Of the 458 children: 15 did not provide serum #1, 17 had prior vaccination, 2 had prior infection, 18 moved, 7 failed to provide serum #2, 12 withdrew (only 1 cited vaccine adverse reactions as the reason). Three hundred and eighty-seven (210 males, 177 females) aged 11.8-14.2 years (mean: 12.9+/-0.42 years) at entry completed both injections 321-381 days (mean: 359+/-10.7 days) apart and supplied serum #2, 30-57 days (mean: 41+/-5.6 days) after the second vaccine dose.Anti-HBs responses: 379 of the 387 subjects (97.9%; 95% CI: 95.9-99.1%) achieved anti-HBs > or =10 mIU/ml (range 10-170,460 mIU/ml, geometric mean concentration (GMC) 4155 mIU/ml-95% CI of mean: 3381-5106 mIU/ml). Sex was the only determinant of anti-HBs concentration (206 males: GMC 3073 mIU/ml-95% CI: 2285-4134 mIU/ml; 173 females: GMC 5944 mIU/ml-95% CI: 4508-7851 mIU/ml; P=0.001). CONCLUSION: A high seroprotection rate and GMC were achieved using two 20 micro g doses of Engerix-B administered 12 months apart. These results are similar to those achieved by others using 6-month three- and two-dose regimens in adolescents.