Malaria cases in China acquired through international travel, 2013-2022

BACKGROUND

Despite the World Health Organisation certifying China malaria-free in 2021, the risk of local transmission caused by imported malaria cases remains a significant clinical and public health issue. It is necessary to present the changing trends of malaria in China and discuss the role of travel medicine services in consolidating malaria elimination.

METHODS

This study systematically reviewed articles and reports related to human malaria from 2013 to 2022 published in international and Chinese databases. Data on malaria (i.e. number of cases, Plasmodium spp., diagnostic method, country of acquisition, provinces with high risk of re-introduction and transmission) were collected and synthesised, then summarised using descriptive statistics.

RESULTS

Overall, 24 758 cases of malaria (>99.5% laboratory confirmed, > 99.2% imported, 0.5% fatal) were reported in China from 2013 to 2022, with a downward trend over the years (4128 cases in 2013 compared to 843 cases in 2022; χ2 trend p-value = 0.005). The last locally acquired case was reported in 2017. P. falciparum (65.5%) was the most common species identified, followed by P. vivax (20.9%) and P. ovale (10.0%). Two Pheidole knowlesi cases were also identified in 2014 and 2017 in returned travellers from Malaysia and Indonesia, respectively. The most common countries of malaria acquisition were Ghana, Angola, and Myanmar. P. vivax was mainly detected in returned travellers from Myanmar, while P. falciparum and P. ovale were detected in travellers from Sub-Saharan Africa. Imported cases were mainly reported in Yunnan, Jiangsu, Sichuan, Guangxi, Shandong, Zhejiang, and Henan provinces, where large numbers of Chinese people travel overseas for work.

CONCLUSION

Returned travellers from malaria-endemic countries pose a significant risk of malaria re-introduction to China. Travel medicine should be strengthened to improve the capacity and accessibility of both pre- and post-travel services, including malaria prophylaxis and prompt diagnosis of illness in returned travellers.

Use of Dengvaxia® in Australian Travellers: a case series

Dengvaxia is the only licensed dengue vaccine in Australia, but rarely used. We report the experience of using Dengvaxia in seven Australian travellers. Main reasons for opting for vaccination were travel to dengue-endemic regions and severe symptoms during the prior dengue infection. The vaccine was well tolerated by all travellers.

Sexual and reproductive health integration into pre-travel consultations: a scoping review

BACKGROUND

Casual sex during travel is a major preventable factor in the global transmission of sexually transmissible infections (STI). Pre-travel consults present an excellent opportunity for practitioners to educate travellers about sexual and reproductive health (SRH) and safety. The scoping review aims to explore and understand the extent to which SRH is included in pre-travel consultations.

METHODS

PubMed, Embase, CINAHL, Scopus, Medline and Web of Science were systematically searched for primary research articles exploring whether health care practitioners (HCP) included SRH in pre-travel consultations. Extracted findings were synthesised and presented in narrative form.

RESULTS

Findings across 13 articles suggest HCP infrequently broached SRH in pre-travel consultations with HCP discomfort, and lack of time and resources presented as key barriers. Urban practice settings, HCP experience, training in travel medicine, and traveller characteristics such as sexual orientation were positively correlated with discussions about SRH. SRH advice reported was general in nature, primarily focusing on safer sex, condoms, or unspecified STI advice. Risk assessments based solely on age or stereotypes around sexual preferences led to key aspects of SRH care being missed for some (e.g. SRH was less likely to be discussed with older travellers).

CONCLUSIONS

HCPs frequently miss opportunities to integrate SRH into pre-travel consultations. Strategies to promote HCP confidence and awareness present a promising means to boost the frequency and quality of SRH advice disseminated. Integrating culturally safe and responsive SRH history-taking and advice into pre-travel consultations may contribute to global reductions in STI transmission and promote traveller SRH well-being.

The provision of sexual and reproductive health information and services to travellers: an exploratory survey of Australian travel medicine clinicians

BACKGROUND

International travel can increase the risk of exposure to infectious diseases including sexually transmissible infections (STI). Pre-travel medical consultation provides an opportunity for travel-related health risk assessments and advice. This study explored how travel medicine clinicians integrate sexual and reproductive health (SRH) services into clinical practice.

METHODS

A convenience sample of travel medicine clinicians completed a cross-sectional survey online or via hard-copy disseminated at an annual national Australian travel medicine conference.

RESULTS

Of the 67 respondents, most (n , 51; 76.1%) had a postgraduate qualification relevant to travel medicine and 55.2% (n , 37) had worked in travel medicine for over 10years. Only 22.4% (n , 15) reported conducting a SRH history/STI risk assessment for all travel patients. STI testing pre-departure was conducted on patient request (48, 71.6%), if symptomatic (32, 47.8%) or based on risk history (28, 41.8%). SRH information pre-departure was most frequently provided if prompted by patient questions (n , 42; 62.7%), or based on the patient's history (n , 37; 55.2%). Over half the sample (n , 40; 59.7%) expressed interest in further training in SRH.

CONCLUSION

Providing and engaging with additional training may assist travel medicine clinicians to take a more proactive approach to SRH consultations and STI testing. Additional research is needed to explore models of care that will allow comprehensive SRH and STI services to be integrated into standard pre- and post-travel care.

A decision support tool for risk-benefit analysis of Japanese encephalitis vaccine in travellers

BACKGROUND

During pre-travel consultations, clinicians and travellers face the challenge of weighing the risks verus benefits of Japanese encephalitis (JE) vaccination due to the high cost of the vaccine, low incidence in travellers (~1 in 1 million), but potentially severe consequences (~30% case-fatality rate). Personalised JE risk assessment based on the travellers' demographics and travel itinerary is challenging using standard risk matrices. We developed an interactive digital tool to estimate risks of JE infection and severe health outcomes under different scenarios to facilitate shared decision-making between clinicians and travellers.

METHODS

A Bayesian network (conditional probability) model risk-benefit analysis of JE vaccine in travellers was developed. The model considers travellers' characteristics (age, sex, co-morbidities), itinerary (destination, departure date, duration, setting of planned activities) and vaccination status to estimate the risks of JE infection, the development of symptomatic disease (meningitis, encephalitis), clinical outcomes (hospital admission, chronic neurological complications, death) and adverse events following immunization.

RESULTS

In low-risk travellers (e.g. to urban areas for <1 month), the risk of developing JE and dying is low (<1 per million) irrespective of the destination; thus, the potential impact of JE vaccination in reducing the risk of clinical outcomes is limited. In high-risk travellers (e.g. to rural areas in high JE incidence destinations for >2 months), the risk of developing symptomatic disease and mortality is estimated at 9.5 and 1.4 per million, respectively. JE vaccination in this group would significantly reduce the risk of symptomatic disease and mortality (by ~80%) to 1.9 and 0.3 per million, respectively.

CONCLUSION

The JE tool may assist decision-making by travellers and clinicians and could increase JE vaccine uptake. The tool will be updated as additional evidence becomes available. Future work needs to evaluate the usability of the tool. The interactive, scenario-based, personalised JE vaccine risk-benefit tool is freely available on www.VaxiCal.com.

Immune response after rabies pre-exposure prophylaxis and a booster dose in Australian bat carers

Periodic vaccination against rabies is essential for individuals at continuing risk of rabies exposure. There is limited evidence on long-term immunogenicity after a 3-dose intramuscular (3IM) pre-exposure prophylaxis (PrEP) and single IM booster dose, thus current guideline recommendations differ in the interval for serology tests following PrEP and boosters. This study investigated post-PrEP and post-booster persistence of antibodies in Australian bat carers. Bat carers who received 3IM PrEP/booster doses and had post-PrEP/booster serology test results were included. The proportion of antibody-negative (<0.5 EU/mL) individuals after PrEP/booster dose were examined. Three hundred and five participants (65.6% females, median age at PrEP 43.1 years) were included. The proportion who were antibody-negative varied depending on the time between 3IM PrEP and the serology test: 8.0% <1 year, 29.8% 1-2 years, 21.2% 2-3 years and 7.7% >3 years. Ninety-one participants receiving booster doses were further assessed. Only one participant was antibody-negative at >3 years after receiving one IM booster dose. Our findings support that a serology test should be performed 1 year after 3IM PrEP, followed by first booster if required. Rabies antibodies persist for many years after receiving the booster doses. The interval between subsequent serology tests and the first booster dose should be no longer than 3 years. Future studies are required to provide more insight into the most appropriate timing of subsequent boosters.

The Emergence of Japanese Encephalitis in Australia and the Implications for a Vaccination Strategy

Japanese encephalitis (JE) is the leading cause of viral encephalitis in Asia. Until 2022, only six locally transmitted human JE cases had been reported in Australia; five in northern Queensland and one in the Northern Territory. Thus, JE was mainly considered to be a disease of travellers. On 4 March 2022, JE was declared a ‘Communicable Disease Incident of National Significance’ when a locally acquired human case was confirmed in southern Queensland. By 11 May 2022, 41 human JE cases had been notified in four states in Australia, in areas where JE has never been detected before. From this perspective, we discuss the potential reasons for the recent emergence of the JE virus in Australia in areas where JE has never been previously reported as well as the implications of and options for mass immunisation programs if the outbreak escalates in a JE virus-immunologically naïve population.

Persistence of antibodies, boostability, and interchangeability of Japanese encephalitis vaccines: A systematic review and dose-response meta-analysis

BACKGROUND

The burden of Japanese encephalitis (JE) is substantial and is arguably one of the most serious viral encephalitic diseases with high case fatality and no specific treatment. JE vaccines are the only available mean to prevent the disease; however, the long-term persistence of antibodies, boostability, and interchangeability between different vaccine classes are not well understood.

METHODS

To summarise the evidence, PubMed, Embase, and Cochrane CENTRAL were systematically searched from their inception to March 2021. Dose-response meta-analysis was utilised to synthesise the proportion of individuals who were seropositive over time after a primary vaccination course and a booster dose. Proportion meta-analysis was conducted to estimate the proportion of individuals who were seropositive as well as those who reported adverse events following a booster dose with a different vaccine class.

RESULTS

Of 1053 publications retrieved, 27 studies with 4,558 participants were included. Of these, 11 studies assessed persistence of antibodies, 14 studies boostability, and 8 vaccine class interchangeability. The pooled seropositivity, 1-year after primary vaccination was 83.4% (95 %CI 78.2-89.5%) and remained stable for up to 5 years (82.7%; 95 %CI 76.1-89.4%). Rapid anamnestic response was observed 10 days post-booster dose, the proportion of individuals who were seropositive reached 96.9% (95 %CI 95.9-97.8%) and remained > 95% for up to 6 years. Inactivated mouse brain-derived vaccines followed by a booster dose of a different vaccine class was effective (i.e. seropositive 99%) and well tolerated.

CONCLUSIONS

A booster dose after the primary vaccination is effective and further booster doses may be needed after 7 years. Inactivated mouse brain-derived vaccine followed by a booster with a newer vaccine class is effective and safe; although, there is a paucity of data related to newer classes of vaccines interchangeability.

Long-term persistence of antibodies and boostability after rabies intradermal pre-exposure prophylaxis

BACKGROUND

Currently, there is limited data on long-term persistence of antibodies and boostability of intradermal (ID) rabies pre-exposure prophylaxis (PrEP) schedules. This study investigated travellers who received a primary ID PrEP schedule at least 5 years previously to determine the persistence of antibodies and subsequent antibody response after one 0.1-ml ID booster dose.

METHODS

Adults (age ≥ 18 years) who had previously received ID PrEP at a specialist travel medicine clinic in Brisbane, Australia were included. At Day 0, blood was collected for serology and one dose of 0.1-ml ID rabies vaccine (Verorab®) was administered. At Day 7, serology was repeated. At Day 14, participants were given results and enquired if they experienced adverse events following immunization (AEFIs). Antibodies were measured using Platelia Rabies II ELISA; levels ≥0.5 EU/mL were considered antibody-positive.

RESULTS

158 participants were included [64.6% female, median age at enrolment 56.4 years, interquartile range (IQR) 42.4-65.2 years], and median time since the primary ID PrEP was 8.5 years (IQR 6.9-11.7 years). The majority of participants (82.3%) were antibody-positive at Day 0. The proportion of participants who were antibody-positive at Day 0 was higher among those who were younger at primary vaccination (87.0% if aged<50 years, 75.8% of aged ≥50 years). The proportion of participants who were antibody-positive declined as median time since primary vaccination increased, though the trend was not statistically significant (p-trend = 0.187). All except one participant (99.4%) were antibody-positive after one ID booster dose. AEFIs were reported by 42.4% of participants and were mainly mild.

CONCLUSIONS

Rabies antibodies persist for many years after ID PrEP and can be rapidly boosted with a single ID dose. Future studies are needed to confirm that ID PrEP primes the immune system sufficiently so that boosters are not routinely needed, and only given in the event of a rabies-prone exposure.

High rate of asymptomatic colonization with antimicrobial-resistant Escherichia coli in Australian returned travellers

Global movement of people plays a key role in the spread of antimicrobial resistant (AMR) organisms. We found that 58% of Australian travellers returning from Asia were asymptomatic carriers of AMR Escherichia coli, including resistance to critically important antibiotics. Future studies are needed to identify interventions for travellers to reduce their risk of AMR acquisition.

Efficacy of one-dose intramuscular rabies vaccine as pre-exposure prophylaxis in travellers

BACKGROUND

Current guidelines for rabies pre-exposure prophylaxis (PrEP) recommend multiple vaccine doses. Travellers sometimes present for pre-travel consultation with insufficient time to complete standard PrEP schedules. We investigated the efficacy of one-dose intramuscular (IM) vaccine in priming the immune system (as PrEP) by measuring antibody response to simulated post-exposure prophylaxis (PEP).

METHODS

A quasi-experimental pre-post intervention clinical trial was conducted at a specialist travel clinic in Australia. Adults (≥18 years) without a history of rabies vaccination were included. At Visit 1, seronegative status was confirmed and one dose of 0.5 ml IM rabies vaccine (Verorab®) administered. At Visit 2 (≥60 days after Visit 1), serology was repeated and a simulated PEP dose (0.5 ml IM) given on this day and again 3 days later (Visit 3). Serology was repeated at Visit 4 (7 days after Visit 2).

RESULTS

A total of 94 antibody-negative participants were included (<50 years [n = 50]; ≥50 years [n = 44]). At Visit 2, 38.0 and 31.8% of participants aged <50 and ≥50 years were antibody-positive (≥0.5 EU/ml). At Visit 4, all participants were antibody-positive; 82.0 and 47.7% of participants aged <50 and ≥50 years had antibody levels >4 EU/ml, respectively.

CONCLUSIONS

One-dose IM vaccine was effective as PrEP for priming the immune system in both age groups, resulting in rapid development of antibodies 7 days after commencing simulated PEP. If there is insufficient time to complete a standard PrEP schedule, one-dose IM could be considered as an alternative schedule for short trips, rather than not offering travellers any doses at all.Clinical trials registration: ACTRN12619000946112.

Efficacy of a 3-day pretravel schedule of tafenoquine for malaria chemoprophylaxis: a network meta-analysis

BACKGROUND

Chemoprophylaxis with weekly doses of tafenoquine (200 mg/day for 3 days before departure [loading dose], 200 mg/week during travel and 1-week post-travel [maintenance doses]) is effective in preventing malaria. Effectiveness of malaria chemoprophylaxis drugs in travellers is often compromised by poor compliance. Shorter schedules that can be completed before travel, allowing 'drug-free holidays', could increase compliance and thus reduce travel-related malaria. In this meta-analysis, we examined if a loading dose of tafenoquine alone is effective in preventing malaria in short-term travellers.

METHODS

Four databases were searched in November 2020 for randomized controlled trials (RCTs) that assessed efficacy and/or safety of tafenoquine for chemoprophylaxis. Network meta-analysis using the generalized pair-wise modelling framework was utilized to estimate the odds ratio (OR) of malaria infection in long-term (>28 days) and short-term (≤28 days) travellers, as well as adverse events (AEs) associated with receiving loading dose of tafenoquine alone, loading dose of tafenoquine followed by maintenance doses, loading dose of mefloquine followed by maintenance doses, or placebo.

RESULTS

Nine RCTs (1714 participants) were included. In long-term travellers, compared to mefloquine, tafenoquine with maintenance doses (OR = 1.05; 95% confidence interval [CI]: 0.44-2.46) was equally effective in preventing malaria, while there was an increased risk of infection with the loading dose of tafenoquine alone (OR = 2.89; 95% CI: 0.78-10.68) and placebo (OR = 62.91; 95% CI: 8.53-463.88). In short-term travellers, loading dose of tafenoquine alone (OR = 0.98; 95% CI: 0.04-22.42) and tafenoquine with maintenance doses (OR = 1.00; 95% CI: 0.06-16.10) were as effective as mefloquine. The risk of AEs with tafenoquine with maintenance doses (OR = 1.03; 95% CI: 0.67-1.60) was similar to mefloquine, while loading dose of tafenoquine alone (OR = 0.58; 95% CI: 0.20-1.66) was associated with lower risk of AEs, although the difference was not statistically significant.

CONCLUSIONS

For short-term travellers, loading dose of tafenoquine alone was equally effective, had possibly lower rate of AEs, and likely better compliance than standard tafenoquine or mefloquine chemoprophylaxis schedules with maintenance doses. Studies are needed to confirm if short-term travellers remain free of infection after long-term follow-up.

REGISTRATION

The meta-analysis was registered in PROSPERO (CRD42021223756).

HIGHLIGHT

Tafenoquine is the latest approved drug for malaria chemoprophylaxis. A loading dose of tafenoquine (200 mg/day for 3 days before departure) is as effective in preventing malaria in short-term (≤28 days) travellers as chemoprophylaxis schedules of tafenoquine or mefloquine with maintenance doses, allowing travellers to have a 'drug-free holiday'.

Comparison of immunogenicity and safety of licensed Japanese encephalitis vaccines: A systematic review and network meta-analysis

INTRODUCTION

Annually more than 100,000 Japanese encephalitis (JE) cases and 25,000 deaths worldwide are caused by JE virus infection. More than 15 JE vaccines are currently in use worldwide. It is unknown whether any of the vaccines is superior to the others in terms of immunogenicity and safety.

METHODS

Four databases were systematically searched for randomised controlled trials that compared two or more types of JE vaccines. Vaccines were classified into four classes: inactivated mouse brain-derived (oldest class), inactivated Vero cell, live chimeric, and live attenuated. Network meta-analysis was used to generate mixed effect estimates against inactivated mouse brain-derived vaccines for seroconversion, and against placebo for adverse event (AE) and severe adverse event (SAE).

RESULTS

23 studies (38,496 participants) were included. All newer vaccine classes had better immunogenicity, the difference was statistically significant for inactivated Vero cell (OR = 2.98; 95 %CI: 1.02-8.65) and live chimeric (OR = 5.93; 95 %CI: 1.73-20.32) vaccines. Inactivated mouse-derived vaccines had the highest odds for AEs (OR = 2.27; 95 %CI: 1.59-3.23), the odds of AE of newer vaccines was not different to placebo. There was no difference in SAEs across vaccine classes.

CONCLUSIONS

All newer JE vaccines have comparable safety profiles, live chimeric and inactivated Vero cell vaccines are the most immunogenic among the newer vaccine classes.

Adverse Events Following Immunization With Combined vs Concurrent Monovalent Hepatitis A and Typhoid Vaccines in Children

Combined hepatitis A and typhoid vaccine is available in Australia, but licensed for use from age 16 years; however it is used "off-label" in children. The combined vaccine is well tolerated in children aged 2-16 years and the risk of adverse events is similar to those receiving concurrent monovalent vaccines.

Immunogenicity after pre- and post-exposure rabies vaccination: A systematic review and dose-response meta-analysis

BACKGROUND

There are a myriad of vaccine schedules for rabies pre- (PrEP) and post-exposure prophylaxis (PEP) that differ in the number and timedoses, number of visits, length of schedule, and route of administration. The objective of this study was to systematically review the evidence and investigate how thedifferences in schedules influence titres over time.

METHODS

Four databaseswere searched from inception to January 2020 for rabies PrEP and PEP studies. Adose-response meta-analysis was utilised to pool geometric mean titres (GMT) over time. Subgroup analyses by route of administration, age group, and schedule were conducted.

RESULTS

80 studies met the inclusion criteria and contributed with 191 datasets and 12,413 participants. Both intradermal (ID) and intramuscular (IM) PrEP/PEP produce adequate GMTs. Significantly lower GMT levels were achieved in older (>50yrs) compared to younger (<50yrs) participants. Short 1-week schedules were as effective as longer schedules that can take between 3 and 12 weeks to complete.

CONCLUSIONS

Several effective ID and IM schedules were identified, the selection of a schedule should take into account the patient's needs, costs, availability to return for subsequent doses, and the time required to complete the schedule. Older individuals warrant special attention as they develop lower antibody response.

Could intradermal be an economical alternative route of administration for Japanese encephalitis vaccines?

Highlight Uptake of Japanese encephalitis (JE) vaccine remains low among travellers, with cost of vaccines likely being one of the main hurdles. We found that smaller doses of JE vaccine administered via intradermal (ID) had similar effect on seroconversion than standard doses administered via subcutaneous. ID is a cheaper yet effective route of JE vaccine administration, and could potentially increase vaccination uptake among travellers.

Neutralizing antibody persistence in pediatric travelers from non-JE-endemic countries following vaccination with IXIARO® Japanese encephalitis vaccine: An uncontrolled, open-label phase 3 follow-up study

BACKGROUND

In an initial study among children from non-Japanese encephalitis (JE)-endemic countries, seroprotection rates remained high 6 months after completion of the primary series with IXIARO®.

METHODS

In this open-label follow-up study, a subset of 23 children who received a 2-dose primary series of IXIARO® in the parent study, were evaluated for safety and neutralizing antibody persistence for 36 months.

RESULTS

Seroprotection rates (SPRs) remained high but declined from 100% one month after primary immunization to 91.3% at month 7 and 89.5% at month 36. Geometric mean titers (GMTs) declined considerably from 384.1 by day 56-60.8 at month 36. No long-term safety concerns were identified.

CONCLUSIONS

The substantial decline in GMT observed in this study, together with previously published data on children vaccinated with IXIARO® support the recommendation for a booster dose in children who remain at risk of JE from 1 year after the primary series of IXIARO®, consistent with the recommendation for adults.

CLINICAL TRIAL REGISTRY NUMBER

NCT01246479.

Risk factors for acquisition of multidrug-resistant Enterobacterales among international travellers: a synthesis of cumulative evidence

BACKGROUND

Recent studies have shown that over 50% of people travelling to Southeast Asia return colonized with multidrug-resistant Enterobacterales (MRE) including carbapenemase-producing Enterobacterales. Importation of MRE by travellers and subsequent spread to family members, communities and healthcare facilities poses real risks that have not yet been adequately assessed. This systematic review and meta-analysis aims to quantify the risk factors and interventions for reducing the risk of MRE acquisition among international travellers.

METHODS

A systematic search was conducted in PubMed, Web of Science and Scopus for analytical epidemiological studies containing data post-2000 that assessed the risk factors to acquire and/or interventions to reduce the risk of MRE acquisition in travellers. Two researchers independently screened all the studies and extracted the information, and disagreements were resolved through consensus. The proportions of MRE acquisition by the region of destination and the odds ratio (OR) for the different risk factors and/or interventions were pooled using the inverse variance heterogeneity model.

RESULTS

A total of 20 studies (5253 travellers from high-income countries) were included in the meta-analysis. South Asia [58.7%; 95% confidence interval (CI), 44.5-72.5%] and Northern Africa (43.9%; 95% CI 37.6-50.3%) were the travel destinations with the highest proportion of MRE acquisition. Inflammatory bowel disease (OR 2.1; 95% CI 1.2-3.8), use of antibiotics (OR 2.4; 95% CI 1.9-3.0), traveller's diarrhoea (OR 1.7; 95% CI 1.3-2.3) and contact with the healthcare system overseas (OR 1.5; 95% CI 1.1-2.2) were associated with MRE colonization. Vegetarians (OR 1.4; 95% CI 1.0-2.0) and backpackers (OR 1.5; 95% CI 1.2-1.8) were also at increased odds of MRE colonization. Few studies (n = 6) investigated preventive measures and found that consuming only bottled water/beverages, meticulous hand hygiene and probiotics had no protective effect on MRE colonization.

CONCLUSIONS

International travel is an important driver for MRE spread worldwide. Future research needs to identify effective interventions to reduce the risk of MRE acquisition as well as design strategies to reduce local transmission on return.

Safety and immunogenicity of an inactivated Vero cell_derived Japanese encephalitis vaccine (IXIARO®, JESPECT®) in a pediatric population in JE non-endemic countries: An uncontrolled, open-label phase 3 study

BACKGROUND

Young travelers to South-East Asia may be at risk for Japanese encephalitis (JE).

METHODS

IXIARO^® (0.25 ml or 0.5 ml, depending on age) were administrated to 100 travelers aged ≥ 2 months to < 18 years. Solicited AEs were collected for 7 days after each injection, unsolicited adverse events (AEs) for a total of 7 months. JE neutralizing antibodies were assessed in 64 subjects.

RESULTS

The most common solicited local AEs were redness (3/12 subjects), induration and tenderness (both 1/12) with 0.25 ml IXIARO^®, and tenderness (44/88) and pain (22/88) with 0.5 ml IXIARO^®. Common solicited systemic AEs were diarrhea (2/12) and loss of appetite (1/12) with 0.25 ml IXIARO^® and muscle pain (27/88) and excessive fatigue (10/88) with 0.5 ml IXIARO^®. In total, up to day 56, AEs were reported by 10/12 (83.3%) of subjects who received the 0.25 ml dose and 67/88 (76.1%) of those vaccinated with the 0.5 ml dose. All subjects (62/62; 100%) developed protective levels of JE neutralizing antibodies by Day 56 and 31/34 (91.2%) retained protective titers at Month 7.

CONCLUSIONS

IXIARO^® was generally well tolerated in children, with an overall AE profile similar to adults. IXIARO^® was highly immunogenic in both dose groups.

Architecture of a transcribing-translating expressome

DNA transcription is functionally coupled to messenger RNA (mRNA) translation in bacteria, but how this is achieved remains unclear. Here we show that RNA polymerase (RNAP) and the ribosome of Escherichia coli can form a defined transcribing and translating "expressome" complex. The cryo-electron microscopic structure of the expressome reveals continuous protection of ~30 nucleotides of mRNA extending from the RNAP active center to the ribosome decoding center. The RNAP-ribosome interface includes the RNAP subunit α carboxyl-terminal domain, which is required for RNAP-ribosome interaction in vitro and for pronounced cell growth defects upon translation inhibition in vivo, consistent with its function in transcription-translation coupling. The expressome structure can only form during transcription elongation and explains how translation can prevent transcriptional pausing, backtracking, and termination.

Twitter for travel medicine providers

Travel medicine practitioners, perhaps more so than medical practitioners working in other areas of medicine, require a constant flow of information to stay up-to-date, and provide best practice information and care to their patients. Many travel medicine providers are unaware of the popularity and potential of the Twitter platform. Twitter use among our travellers, as well as by physicians and health providers, is growing exponentially. There is a rapidly expanding body of published literature on this information tool. This review provides a brief overview of the ways Twitter is being used by health practitioners, the advantages that are peculiar to Twitter as a platform of social media, and how the interested practitioner can get started. Some key points about the dark side of Twitter are highlighted, as well as the potential benefits of using Twitter as a way to disseminate accurate medical information to the public. This article will help readers develop an increased understanding of Twitter as a tool for extracting useful facts and insights from the ever increasing volume of health information.

The tolerability of a combined hepatitis A and typhoid vaccine in children aged 2-16 years: an observational study

BACKGROUND

Combined hepatitis A and typhoid vaccines have been widely used globally and proven to be safe, well tolerated and efficacious in adults. The combined hepatitis A and typhoid vaccine (Vivaxim) available in Australia is licenced for use from age 16 years but the monovalent components are approved for use from age 2 years. Advantages of a single injection have led to widespread 'off-label' use of Vivaxim in children. This study aimed to investigate the tolerability of Vivaxim in children aged 2-16 years.

METHODS

A prospective observational study was conducted at Travel Medicine Alliance clinics across Australia. Children who required vaccination for both hepatitis A and typhoid were offered the option of receiving Vivaxim. Parents were contacted 3 days post-vaccination and asked to respond to a questionnaire on adverse events following immunization (AEFIs). Reactions to Vivaxim were compared with reported reactions to the monovalent vaccines.

RESULTS

Our study included 425 children who received Vivaxim, including 189 (44.5%) who received other vaccines on the same day. No serious AEFIs were reported, and 26.8% did not experience any side effects. In children who did not receive other vaccines in the same arm as Vivaxim (n = 325), most common local reactions were sore arm (70.5%), redness (16.0%) and swelling (11.1%). Reports of local AEFIs in our subjects was significantly more common than those reported for the individual monovalent vaccines. In children who did not receive other vaccines on the same day (n = 236), the most common systemic reactions were tiredness/lethargy/malaise (5.9%), headache (4.2%), fever (3.4%) and sore muscles and joints (3.4%). Fever was more common in children aged <6 years. Less than 5% of children reported missing school, sport or other regular activities.

CONCLUSIONS

Vivaxim was well tolerated in children aged 2-16 years. Parents should be advised about AEFIs to Vivaxim so that they can make informed decisions about vaccination options.

Animal bites and rabies exposure in Australian travellers

OBJECTIVES

To examine the circumstances of animal exposure in a case series of Australian travellers who required rabies postexposure prophylaxis, and to assess the appropriateness of current guidelines for rabies pre-exposure vaccination.

DESIGN, PARTICIPANTS AND SETTING

Prospective case series of 65 returned travellers who presented to four Australian travel medicine clinics between 1 April 2009 and 31 July 2010 for rabies post-exposure prophylaxis.

MAIN OUTCOME MEASURES

Demographic characteristics associated with risk of injury; countries where injuries occurred; circumstances of the injuries; and travellers' experiences of obtaining postexposure prophylaxis overseas.

RESULTS

Animal bites and scratches occurred most commonly among travellers aged 20-29 years. Most injuries occurred in Bali, Indonesia (30 [46%]) and Thailand (21 [32%]), and the most common animals responsible for the injuries to the 65 travellers were monkeys (29 travellers [45%]) and dogs (27 [42%]). Thirty-nine of the travellers (60%) initiated contact with the animal. Forty travellers (62%) were able to commence rabies vaccination overseas, but only nine (14%) were able to obtain rabies immunoglobulin overseas.

CONCLUSIONS

Most travellers had difficulty obtaining rabies postexposure prophylaxis overseas, resulting in significant delays in appropriate treatment. We recommend that current National Health and Medical Research Council guidelines for at-risk persons be broadened, and that the risk of rabies and the option of pre-exposure vaccination be discussed with all travellers to rabies-endemic areas.

The immunogenicity of a modified intradermal pre-exposure rabies vaccination schedule--a case series of 420 travelers

BACKGROUND

Current Australian recommendations for rabies pre-exposure vaccination involve the use of cell-culture-based rabies vaccines, which are administered via intramuscular (IM) or intradermal (ID) routes. ID vaccination is more affordable for travelers, but is only recommended if there is sufficient time to perform serology 2 to 3 weeks post-vaccination and confirm immunity prior to travel. We report the immunogenicity of a modified ID schedule that can be completed in less time than the standard ID schedule, and allow more travelers to be vaccinated prior to departure.

METHODS

Travelers were offered a modified schedule if they were unable to afford standard IM vaccinations, and did not have time to complete a standard ID course. The modified schedule consisted of two ID injections of 0.1 mL of human diploid cell rabies vaccine administered on days 0 and 7, and serology was performed to determine immune status at a time between day 21 and 28.

RESULTS

A total of 420 travelers aged between 10 and 65 years were vaccinated using the modified ID course. The overall seroconversion rate was 94.5%, with 397 travelers developing antibody levels of >0.5 IU/mL when tested at approximately 21 days post-vaccination.

CONCLUSION

The modified ID schedule used in this case series was highly effective, had similar immunogenicity to the standard ID schedule, and should be considered in travelers who are unable to complete standard IM or standard ID courses of rabies vaccines.

Abstract P2-06-14: Utilizing Human Breast Tissue and Blood to Discern Novel Protective Properties of Early Pregnancy in Reducing Breast Cancer Risk

Introduction: The incidence of breast cancer, the most common cancer in women, is very high in Western Countries and is increasing rapidly in the Third World. Yet, despite better screening, earlier diagnosis, and the development of new therapies, a cure for metastatic breast cancers remains an elusive goal. Since it is difficult to defeat breast cancer after it has occurred, finding new strategies to delay or prevent the development of breast cancer has been an important area for clinical and experimental investigations. Multinational studies have suggested that women who undergo a full-term pregnancy before the age of 20, with or without lactation, have about one half the risk of developing breast cancer compared to women who undergo their first pregnancy after the age of 35 or women who have never undergone a full term pregnancy. Thus, pregnancy at an early age protects against breast cancer development. This universal protective effect of pregnancy serves as a major clue and starting point in the search for new experimental strategies and novel biomarkers related to the prevention of breast cancer.

Methods: Women were recruited who had never been diagnosed with breast cancer and fit in one of the following categories; 1) had their first child ≥25 years of age, 2) had their first child ≥35 years of age, and 3) a control group of women the same age as those in groups 1 and 2 but who have never given birth were recruited and provided a sample of breast tissue and blood simultaneously. These groups were categorized as early parous, late parous, or nulliparous and their RNA was isolated from tissue and whole blood. Human whole genome microarray analysis (Agilent) was performed to identify the genes that were persistently altered in expression due to early pregnancy.

Results: The study of molecular alterations in breast cancer genes has succeeded in identifying some genetic mechanism of breast cancer development. We attempted to elucidate early pregnancy-related changes in genes in breast tissue and blood associated with resistance to breast cancer. Over 2200 genes were up-regulated 2 folds or more in the blood and breast of early parous women than late parous and nulliparous women. Approximately 5000 genes were down-regulated 2 folds or more in the blood and breast of early parous women compared to late parous and nulliparous women.

Conclusion: These studies focused on the analysis of human breast tissue and blood to gain a deeper understanding of changes in parity associated with the protective effect of early pregnancy in women. From these altered gene expressions we have identified a gene signature for early parity. The persistently altered genes will be used as novel biomarkers to predict breast cancer risk and develop strategies to protect the breast from cancer development.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-06-14.

Projection structure of the monomeric porin OmpG at 6 A resolution

The Escherichia coli porin OmpG, which acts as an efficient unspecific channel for mono-, di- and trisaccharides, has been purified and crystallized in two dimensions. Projection maps of two different crystal forms of OmpG at 6 A resolution show that the protein has a beta-barrel structure characteristic for outer membrane proteins, and that it does not form trimers, unlike most other porins such as OmpF and OmpC, but appears in monomeric form. The size of the barrel is approximately 2.5 nm, indicating that OmpG may consist of 14 beta-strands. The projection map suggests that the channel is restricted by internal loops.

Efficacy of metformin in type II diabetes: results of a double-blind, placebo-controlled, dose-response trial

PURPOSE

To study the efficacy and safety of various dosages of metformin as compared with placebo in patients with type II diabetes mellitus.

PATIENTS AND METHODS

A 14-week, multicenter, double-blind, dose-response study was conducted. After a 3-week, single-blind, placebo-controlled washout, 451 patients with fasting plasma glucose levels of at least 180 mg/dL were randomized to receive an 11-week course of placebo or metformin given at 500, 1000, 1500, 2000, or 2500 mg daily.

RESULTS

Metformin improved glucose variables as compared with placebo. The adjusted mean changes in fasting plasma glucose from baseline associated with each metformin group at week 7, 11, or at endpoint exceeded those associated with placebo by 19 to 84 mg/dL at dosages of 500 to 2000 mg daily, respectively. The corresponding between-group differences in glycated hemoglobin (HbA1c) ranged from 0.6% to 2.0% at dosages of 500 to 2000 mg daily, respectively. All between-group differences were significant (P < 0.05) for both fasting plasma glucose and HbA1c at week 7, week 11, and endpoint, except for the difference between placebo and metformin 500 mg in fasting plasma glucose at endpoint (P = 0.054). Treatment-related adverse events occurred in 15% of patients in the placebo group and in 28% in the metformin group (P = 0.02); these were primarily manifested as digestive disturbances, such as diarrhea.

CONCLUSIONS

Metformin lowered fasting plasma glucose and HbA1c generally in a dose-related manner. Benefits were observed with as little as 500 mg of metformin; maximal benefits were observed at the upper limits of the recommended daily dosage. All dosages were well tolerated. Metformin appears to be a useful therapeutic option for physicians who wish to titrate drug therapy to achieve target glucose concentrations.

Evaluation of the CASPAR alcohol education curriculum

The CASPAR education-prevention program was initiated when experimental results indicated that a 5-hr alcohol education curriculum at a Catholic high school was able to reduce frequent intoxication among teenagers. Attempts to institutionalize such a program in the public schools shows that (1) alcohol education can generate widespread community and school support; (2) workshops can successfully train teachers to adopt a decision-making approach, though close supervision is needed to ensure that this approach is adhered to in classroom teaching; (3) the CASPAR model of alcohol education produces classroom situations conducive to many children feeling free to express alcohol-related concerns; (4) trained teachers can serve as intermediaries between students with alcohol-related concerns and community resources, in particular those resources that are designed to help children from families with alcoholism; (5) the CASPAR curriculum, implemented by trained teachers, produces statistically significant knowledge and attitude gains, whereas alternate programs such as a special-events approach produce smaller knowledge gains and little attitude change; and (6) to a considerable extent, knowledge and attitude gains persist over time, although retention is greater on knowledge items and among older students. The results suggest that there may be a behavioral impact of instruction in the form of reduced alcohol misuse among teenagers, although if there is, it requires intensive and repeated exposure and can be demonstrated in these data only among younger students while they remain in junior high school. Although such results may be viewed as less supportive than the original experiment with which this work began, they do suggest that alcohol education remains an effective prevention strategy.

Developmental patterns of alcohol dehydrogenase and aldehyde dehydrogenases in homogenates and subcellular fractions of rat liver

Both alcohol dehydrogenase (ADH) and the two isoenzymes of aldehyde dehydrogenase (ALDH-I-NAD+ and ALDH-II-NAD+) were first detected in foetal rat liver about 5 days before birth. All enzymes developed gradually and showed no abrupt increases in activity. The specific activities of ALDH-I-NAD+ and ALDH-II-NAD+ in the mitochondrial fractions, ALDH-II-NAD+ in the microsomal fractions and ADH in liver homogenates all produced a major percentage of the adult activity within a month, whereas the total activities increased over a longer part of the developmental period.

Lipid peroxidation of the microsomal fraction and extracted microsomal lipids from DAB-induced hepatomas

NADPH- and ascorbic acid-induced microsomal lipid peroxidation was almost absent in subcutaneously implanted DAB-induced hepatomas D23, D30 and D192A, and present at greatly reduced levels in DAB-induced primary hepatomas when compared with normal liver controls. Fatty acid analysis of the microsomal lipid from passaged tumours demonstrated adequate levels of substrate in the phospholipid fractions to support lipid peroxidation. Lipid extracted from hepatoma microsomal fractions was shown to undergo ascorbic acid-induced lipid peroxidation, but to a lesser extent that the corresponding liver extract. This may be partially explained by a decrease in the phospholipid content of hepatoma microsomal membranes. However, phospholipid extracted from microsomal fractions of hepatoma and liver supported lipid peroxidation to a similar extent. The possible role of the non-lipid component of the membrane in the process of lipid peroxidation is discussed.

Lowered respiratory activity in hypo-osmotically shocked mitochondria without loss of cytochrome c

Brief exposure of rat liver mitochondria to hypo-osmotic sucrose media caused a decline in the rates of succinate and ascorbate-NNN'N'-tetramethyl-p-phenylenediamine oxidation without loss of cytochrome c when assayed in iso-osmotic media. Lowered respiration rates in mitochondria after brief exposure to hypo-osmotic media may reflect a modification of cytochrome c binding.

Radiological Findings in a Case of Acute Pancreatic Necrosis

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