Infectious diseases

About 80-90% of patients with Buruli ulcer acquired in Far North Queensland present with an ulcer

Michael J Loftus · Nicola Kettleton-Butler · Denton Wade · R Michael Whitby · Paul DR Johnson

To the Editor:In October 2016, we achieved the eradication and control of hepatitis C virus (HCV) in a New South Wales correctional centre, which we believe to be a first of its kind in NSW. HCV prevalence in NSW prisons is 30–40 times higher than in the community, where prevalence is about 1%.1,2 Elevated risk of HCV infection is associated with the high proportion of prisoners who have injected drugs, the rate of injecting in prison, and restricted or limited access to bleach and needle and syringe programs.3 The Justice Health and Forensic Mental Health Network (the Network) is responsible for health care in the NSW forensic mental health and criminal justice systems. The availability of direct-acting antivirals on the Pharmaceutical Benefits Scheme in March 20164 created an opportunity for the Network to cure all patients with HCV infection in one prison. The Compulsory Drug Treatment Program (CDTP) is run at the Compulsory Drug Treatment Correctional Centre — a stand-alone prison with a stable sentenced inmate population, where patients with repeat drug-related charges participate in comprehensive drug treatment and rehabilitation. Patients at this correctional centre have longer sentences than those in other centres, which allowed for the full course of treatment. The Network, Corrective Services NSW and Hepatitis NSW formed a partnership to ensure that patients were able to access health centres, have their medication scripted and administered, could undertake monitoring and were supported through the Network’s established nurse-led model of care.5 All 58 patients in the CDTP were offered screening, and 54 patients with risk factors were screened; of these, 18 patients had chronic HCV infection. After further work-up, including liver elastography to measure fibrosis, all patients were concurrently commenced on treatment. Of the remaining four patients who were not screened, all had recent negative HCV pathology results. Three months after the treatment, 15 patients achieved sustained virological response equating to cure of their chronic HCV infection, and three patients were released before final assessment.6 Concurrent treatment commencement with the direct-acting antivirals was recognised as an innovative measure in reducing re-infection, in conjunction with the more common practices of harm minimisation education and use of the hospital-grade disinfectant for general cleaning purposes offered by Corrective Services NSW to all incarcerated people. Throughout the course of the project, two new patients were admitted, screened, and returned negative HCV pathology results. A proactive screening approach with patient consent was adopted to ensure that new cases were able to be identified and treated to maintain elimination. Maintaining a prison HCV-free may mean that patients have to take some responsibility with regard to sharing needles with new inmates. A peer education approach is being developed to increase patients’ ownership of a prison’s HCV-free status. The CDTP treatment model, combined with ongoing screening of new admissions, is an innovative approach for eliminating HCV, and is considered suitable for adoption in similar-sized prisons across Australia. The Network is currently rolling out this approach within NSW.

James Blogg · James Wood · Colette McGrath · Camilla Lobo

To the Editor: I found the article by Kiely and colleagues1 very interesting. The authors concluded that “it should be noted that a relatively small number of imported ZIKV [Zika virus] infections have been reported in Australia, there have been no reported cases of local ZIKV transmission, and the geographical distribution of the potential ZIKV mosquito vector in Australia (Aedes aegypti) is limited to northern Queensland,” and that “at present, ZIKV represents a low risk to blood safety in Australia.”1 Indeed, Kiely and colleagues may be correct in their statement. Nevertheless, without supportive evidence, it seems too soon to draw a conclusion. The estimation of the risk or possibility of transfusion-transmitted ZIKV infection in each setting may be based on mathematical modelling with reference to risk of transmission of other arboviruses in that setting. A good example is the previous report on the estimated risk of transfusion-transmitted ZIKV infection in Thailand.2 However, the lack of reports on ZIKV transmission does not mean that the problem does not exist; many patients with ZIKV infection are asymptomatic and can be easily missed.3

Viroj Wiwanitkit

In reply

Philip Kiely · Erica M Wood · Allen C Cheng

To the Editor:I read with interest the call by Menzies and colleagues1 for revitalised efforts to vaccinate a higher proportion of the adult Australian population against common infectious diseases. At present, the aim of the adult component of the National Immunisation Program is to protect against Streptococcus pneumoniae and the two viruses that cause influenza and herpes zoster — all prevalent pathogens in our environment. In addition to infections derived in Australia, adults are more likely than children to be the focus of imported cases of infection. Exposure of adults to, for instance, tropical infectious diseases, including those transmitted by biting insects (ie, dengue, yellow fever, chikungunya and Zika viruses, malaria, etc), will be far greater than that of juveniles. This is because adults have more reason to travel overseas and typically undertake more trips than children do.2 Vaccine uptake among travellers is mixed, and there are groups that are not sufficiently vaccinated, including people who travel overseas to visit friends and relatives (VFR). These so-called VFR travellers are more likely to consider themselves at low personal risk or threat when travelling to their country of origin, stemming from a sense of familiarity with the destination country and its infectious disease risks.3 Cultural beliefs and language barriers are also important factors associated with suboptimal uptake of pre-travel advice among VFR travellers. While infants accompany their parents for holidays and to visit family abroad, intercontinental travel for business and educational opportunities is largely restricted to adults.4 For typical short stay business trips, rather than for holidays lasting an extended period, it is tempting to neglect being up to date with vaccinations.2 In this instance, for the busy business flyer — often a last-minute traveller — the risk aversion to illness may be suppressed by avoidance of the perceived hassle of immunisation. Travel acts as a vector for spread of infection and many outbreaks are imported into Australia through overseas trips; nevertheless, travellers frequently neglect to seek pre-travel health advice.5 Improving rates of travel vaccination, especially in adults, is one area of focus that may help infectious disease control efforts nationally.

Andrew W Taylor-Robinson

In reply

Robert I Menzies · Jenny Royle · C Raina MacIntyre

To the Editor:While vaccine refusal is but one contributor among several to failures of vaccine-preventable disease control, as stated by Beard and colleagues,1 there are important ethical aspects of vaccine refusal. Intentionally opting out of vaccination imposes risks on others, and policies allowing some to opt out weigh their freedom to do so against the rights of others not to be harmed by vaccine-preventable diseases.2 In particular, people who cannot be safely vaccinated (eg, infants) or maintain immunity (eg, the immunosuppressed) are at increased risk of severe disease — including death — and depend on the immunity of others.2 It is true that herd immunity has no “magic threshold”:1 even with high population vaccination levels, severe harm may be caused when just one unvaccinated person has contact with an infectious person and then a vulnerable person. The death of an immunosuppressed woman from measles pneumonitis in the state of Washington, United States, in 2015 is a case in point.3 Tighter legislation on universal vaccination does not unfairly target vaccine refusal. Indeed, Victorian No Jab, No Play legislation has a general objective: “to increase immunisation rates for young children,”4 which applies equally to people who have unintentionally failed to vaccinate and those who intentionally opt out due to hesitancy or refusal. Policy should make vaccination the norm and aim for the highest possible coverage. Moreover, while we should revise financial penalties if they unfairly burden poor families (while the wealthy may pay to opt out), policy should, in some way, recognise that conscientious objection to vaccination has consequences for others.5 Measles outbreaks are correlated with vaccine refusal6 and lead to significant social costs, which Australia may avoid if high levels of vaccination are maintained. Though the true epidemiology is certainly more complex, if measles vaccination leads to immunity in 99% of vaccine recipients, and 95% of people are vaccinated,1 the population level of immunity would be 94.05%. Threshold concepts have limitations, but whether this is “comfortably exceeding” 94%,1 or perilously close to recurrent measles outbreaks — which impose avoidable risks of harm on others — is a matter for debate.

Euzebiusz Jamrozik

In reply

Frank H Beard · Julie Leask · Peter B McIntyre