Environmental health

To the Editor: We read with interest the recent article by Bonevski and colleagues1 calling for targeting of tobacco cessation interventions to high-risk populations, including prisoners. People who cycle through prisons in Australia smoke tobacco at a rate five times that of the general population,2 and suffer disproportionately from smoking-related morbidity and mortality.3 However, the suggestion by Bonevski and colleagues1 that smoke-free policies in prisons “impact on reducing smoking” is unfortunately a case of misplaced optimism: although these policies reduce smoking in prisons, they have almost no effect on long term smoking behaviour in people who cycle through prisons. Research in the United States shows that about 60% of people released from smoke-free prisons resume smoking on the day of release,4 and 97% relapse within 6 months of release.5 Preliminary findings from a cross-sectional survey we have conducted with 114 ex-smokers released from smoke-free prisons in Queensland paint a similar picture, with 72% of participants reporting relapse on the day of release. Smoke-free policies in Australian prisons are an important public health initiative and should be supported. However, alone they are insufficient to reduce the remarkably high rates of smoking, and of related morbidity and mortality, in the vulnerable populations who cycle through these institutions. There is an urgent need for development and rigorous evaluation of smoking cessation and relapse prevention interventions targeting people released from prison in Australia. Building on the findings of a recent trial in the United States,4 we have recently been awarded funding from the Victorian Health Promotion Foundation to undertake a double-blinded, randomised controlled trial of an intervention designed to reduce relapse to smoking among people released from smoke-free prisons in Victoria. We hope that our study will provide new evidence to guide future efforts to reduce tobacco-related harm in this population. We echo Bonevski and colleagues’1 call for a comprehensive policy shift aimed at reducing tobacco use among disadvantaged populations in Australia. However, prison smoking bans alone are insufficient. Investment in evidence-based efforts to prevent smoking relapse after release from prison will be critical to reduce tobacco-related health disparities in this profoundly vulnerable, marginalised population and realise this important public health opportunity.

Cheneal Puljević · Stuart A Kinner

In reply

Billie Bonevski · David P Thomas · Robyn L Richmond

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