Background:Amid rising resistance to bedaquiline, aminoglycosides remain an important fallback option for multidrug-resistant tuberculosis (MDR-TB) treatment, particularly in high-burden settings. Their use is limited by nephro- and ototoxicity, which is associated with cumulative drug exposure. In this study we investigated amikacin exposure in Ugandan MDR-TB patients using a validated limited sampling strategy and compared the results to previously published data from a Western European cohort. Methods:In this single-centre prospective observational study, 29 MDR-TB patients received amikacin at a dose of 10-15 mg/kg. Serum levels were measured on day 30 at 1, 4 and 5 h post-administration using liquid chromatography/mass spectrometry. Individual concentration-time curves were modelled using a one-compartment model and compared to a Dutch population-pharmacokinetic (PK) model. Results:Twenty patients had complete PK data. Patients received a median amikacin dose of 10.9 (IQR 10 - 14.9) mg/kg; clearance was 4.79 L/h (IQR 4.03 - 5.75), volume of distribution (Vd) 16.3 L (IQR 14.07 - 21.49), AUC0-24h 125.15 h x mg/l (IQR 106.73 - 174.46), maximum serum concentration (Cmax) 27.8 mg/l (IQR 22.9 - 48.7). Conclusions:This population-PK study shows that major differences in PK between Ugandan MDR-TB patients and those in the Global North are unlikely. Our findings reinforce the suitability of a one-compartment model for therapeutic drug monitoring in both high- and low-resource settings. Readily obtained aminoglycoside PK parameters in a limited resource setting facilitate future efforts in optimizing drug exposure with minimal toxicities, in the population most affected by the pandemic of TB.

Background Diphtheria was a major cause of childhood morbidity and mortality in Switzerland until the mid-20th century. While mortality declined already before vaccination due to improvements in living conditions and medical care, recurrent epidemic waves persisted. The role of vaccination programmes introduced in the 1930s and 1940s has not been systematically quantified for Switzerland. Data and methods We compiled and digitised multiple historical time series on diphtheria morbidity, hospitalisations and mortality in Switzerland from 1877 to 2022, including cantonal incidence data from 1910 onwards. Using Bayesian negative binomial models, we estimated counterfactual incidence and mortality trajectories in the absence of vaccination. We compared observed trends with model predictions, focusing on the early mandatory programme in Geneva (from 1933) and on differences between cantons with mandatory versus recommended/facultative vaccination following the nationwide recommendation in 1943. Results Between 1877 and 2022, 35,271 diphtheria deaths were recorded, with 99.5% occurring before widespread vaccination in the 1940s. Incidence and mortality declined in several stages but were punctuated by major epidemic waves around World War I, 1930, and World War II. After the introduction of mandatory vaccination in Geneva, observed incidence and mortality were consistently lower than predicted counterfactual levels. Following the nationwide vaccination recommendation, diphtheria declined rapidly in all cantons, but reductions were earlier and more pronounced in cantons with mandatory vaccination, which also experienced fewer and smaller residual outbreaks. Discussion Our findings show that while pre-vaccination declines reduced diphtheria burden, sustained containment was only achieved through vaccination.

ObjectivesIn this study, we determined the frequency of clinically relevant mental health conditions among Eritrean and Somali refugees in Basel and Zurich, Switzerland and assessed their levels of resilience.MethodsA cross-sectional study among refugees aged ≥16 years involved validated questionnaires, screening for symptoms of post-traumatic stress disorder (PTSD), somatic disorders, anxiety, depression, and assessments of alcohol use and resilience.ResultsThe 102 participants were young (median age 34 years), Eritrean (N = 88; 86%), males (N = 62), with long periods of staying in Switzerland (median 8.6 years). Almost three-quarters (N = 69/99; 70%) had high resilience scores (median 86). We found low frequencies of moderate or severe symptoms of PTSD (7%), anxiety (0%) and depression (1%). However, symptoms for somatic disorders (18%) and harmful levels of alcohol use (12%) were more common.ConclusionWhile the overall levels of resilience are impressively high, a large proportion of participants exhibited symptoms of somatic disorders and harmful levels of alcohol use - well beyond the early adaptation phase. This highlights the need for long-term mental healthcare beyond the time of arrival to ensure their wellbeing.

Introduction:Human papillomavirus (HPV) is a major cause of cervical cancer and other related diseases. Switzerland has implemented a national HPV immunisation strategy since 2007. This study examined trends in HPV vaccination coverage and valid schedule completion among adolescents in Switzerland between 2008 and 2022 and assessed differences in vaccination outcomes by delivery through school health services. Methods:We analysed data from the Swiss National Vaccination Coverage Survey, including 46 914 sampled adolescents, of whom 32 554 provided vaccination documentation. The analysis included 16-year-old girls (2008-2022) and 16-year-old boys (2017-2022). Vaccination uptake (≥1, ≥2 and ≥3 doses) and valid schedule completion (valid two-dose, valid three-dose and valid total) were estimated using weighted proportions with 95% CIs. Differences between cantons with and without HPV vaccination delivered through school health services were assessed for the 2017-2019 survey period. Multivariable logistic regression was used to evaluate factors associated with valid total schedule completion among girls (2011-2019). Results:Vaccination coverage among 16-year-old girls increased from 28.8% (95% CI 24.4% to 33.2%) in the survey period 2008-2010 to 74.6% (95% CI 72.2% to 77%) in the survey period 2020-2022 for ≥1 dose. Valid schedule completion rose substantially, particularly for the two-dose regimen after the 2012 recommendation change. Among boys, coverage reached 51.2% (95% CI 48.4% to 54%) for ≥1 dose in the survey period 2020-2022. In 2017-2019, completion of a valid HPV schedule among girls was 51.8% (95% CI 48.6% to 54.9%) in cantons with school health services versus 40.8% (95% CI 37.2% to 44.5%) in those without such services. In multivariable analyses, school health services, urban residence and French-speaking region were associated with higher odds of valid schedule completion. Conclusion:HPV vaccination coverage in Switzerland has improved over time, particularly following the introduction of the two-dose schedule. Delivery through school health services was associated with higher coverage and completion, highlighting the importance of organised vaccination delivery strategies.

ObjectivesHealthcare workers (HCWs) are essential in preventing and controlling infectious diseases and can influence public trust in vaccines. This study compares vaccination behaviors among HCWs in a Swiss hospital setting with those in primary care and identifies key factors influencing vaccine acceptance.MethodsAn online questionnaire was distributed to HCWs at a cantonal hospital in Central Switzerland. The results were compared with a previous nationwide survey of German-speaking HCWs in primary care using descriptive statistics, chi-square tests, and multivariable logistic regression analyses.ResultsInfluenza vaccination coverage was 37.2% in hospitals and 59.8% in primary care. COVID-19 vaccination rates were high in both settings (89.1% and 92.7%, respectively). Physicians and older HCWs were significantly more likely to be vaccinated than nurses and younger staff. Vaccination training and prior vaccination history were associated with higher vaccination rates and stronger recommendation behavior. The most common reasons supporting vaccination were self-protection and patient protection.ConclusionVaccination behavior among HCWs differs considerably by healthcare setting and profession. Targeted vaccination training, particularly for younger HCWs and nurses in hospital settings, may help increase vaccine acceptance.

Background and aimsOnline dating applications (ODAs) are gaining popularity, raising concerns about their potential addictive effects on users' health. The main objective of this study was to investigate the association between problematic ODA use and mental health, substance use, and sexual behavior outcomes in men-who-have-sex-with-men (MSM). To achieve this, we first validated a German version of the Problematic ODA Use Scale (PODAUS), which assesses problematic ODA usage patterns.MethodsProblematic ODA use was assessed in 226 HIV-negative MSM counseling for HIV pre-exposure prophylaxis at baseline and 6-month follow-up (n = 164, M-age = 42, SD = 11). The German PODAUS was validated using confirmatory factor analyses (CFA) and correlational analysis. Multiple linear regression analyses were performed to investigate associations of PODAUS with mental, sexual health, and substance use outcomes.ResultsCFA supported PODAUS' 6-item unidimensional structure, demonstrating excellent fit indices. Reliability analyses indicated good internal consistency (alpha = 0.79) and high test-retest reliability (r(s) = 0.68). Regarding mental health, significant positive associations were found between PODAUS and symptoms of depression, loneliness, anxiety, Attention Deficit Hyperactivity Disorder (ADHD), and impulsivity, with medium to large effect sizes. Regarding sexual health, significant negative associations of small to medium effect sizes were found between PODAUS and lifetime prevalence of sexually transmitted infections, body acceptance, and sexual fulfillment, while a significant positive association with trait sex motivation occurred.Discussion and ConclusionThe German version of PODAUS emerges as a valid, reliable tool to assess problematic ODA use. In an MSM sample, problematic ODA use was associated with lower mental and sexual health.

Background:In the context of this paper, airport/seaport malaria denotes the accidental relocation by air or sea of a malaria infected mosquito to Europe, a non-endemic area, the survival of the transported mosquito and subsequent blood meal and infection of a local person. Autochthonous malaria refers to locally transmitted cases of malaria in Europe. Methods:The systematic review followed PRISMA guidelines and was registered on PROSPERO (CRD42023444243). PubMed and Ovid MEDLINE electronic databases as well as EMBASE, Scopus and CINAHL were searched for eligible papers. The selection process followed strict inclusion and exclusion criteria. Results:We included 68 papers describing 115 cases of airport, seaport or autochthonous malaria in Europe, with a total of 68 airport/seaport malaria cases and 47 autochthonous malaria cases. France, Germany, Italy and Spain reported both types of malaria cases. Cases of airport/seaport malaria only were reported from Belgium, Luxembourg, Switzerland and the United Kingdom. Cases of autochthonous malaria only were reported from Greece, Malta and the Netherlands. The case fatality rates for airport/seaport malaria were 13.24 % and for autochthonous malaria 2.13 % respectively. Conclusion:The importance of airport/seaport and autochthonous malaria is related to the frequently delayed or missed diagnosis, leading to high case fatality rates. Rising temperature may facilitate the importation and proliferation of competent Anopheles vectors. Increased human migration and travel with malaria parasite carriage may contribute to the reemergence of autochthonous malaria in Europe.

BackgroundIntegrating sexual health into pre-travel counselling is important to raise risk awareness and ensure travellers have access to preventive measures, including HIV pre-exposure prophylaxis (PrEP). Yet, it is implemented little in practice. This qualitative study describes the experience, perceptions and needs of travellers and health care professionals (HCP) concerning integrating sexual health into pre-travel counselling. It is part of a practice developmental approach strengthening sexual health counsling at the University of Zurich’s Centre for Travel Medicine (CTM), Switzerland.MethodsTravellers attending the CTM as well as HCPs from travel medicine and sexual health care across Switzerland were recruited for semi-structured interviews from August 2022-February 2023. Reflexive thematic analysis with a constructivist orientation was used to analyse data.ResultsInterviews with 24 participants (13 travellers; 11 HCPs) revealed common themes, which were summarized along the metaphor of a theatre play, that is ment to illustrate the counselling dynamic. The overarching theme “The ambiguity of bringing sex and travel into play” describes how both groups face uncertainty about discussing sexual health in pre travel consultations. They find it important but feel uncomfortable due to stigma. “Setting the spotlight on the sideshow of sexual health counselling” highlights the challenge of drawing attention to this often-neglected topic. “Engaging in the performance of sexual health counselling” captures how travellers and HCPs are challenged to interact meaningfully during these conversations, including reflection on personal risk and “Improvising the off-script scene in sexual health counselling” reflects the challenges they face in navigating unexpected or complex counselling content, such as HIV-PrEP.ConclusionsSexual health remains a sensitive and difficult topic to discuss for both travellers and HCPs. Achieving impact will require cultural change to reduce stigma and normalise sexual health discussions. This involves targeted interventions for healthcare providers, including stigma reflection and training in person-centred and motivational communication, as well as interventions for travellers to raise awareness of sexual health as a travel-related issue, and promote reflection on personal risk, and inform about preventive options, including HIV pre-exposure prophylaxis (PrEP). Further research should develop and test a theory of change integrating these elements in clinical practice.

The Coronavirus Disease of 2019 caused an unprecedented drop in air travel. Recovery was influenced by infection waves and different infection control measures. International travel entered a rebound phase in 2022, with more growth forecasted. Now it seems the time to reframe tourism linked to flights and considering planetary health aspects.

BackgroundTick-borne encephalitis (TBE) is a severe, vaccine-preventable viral infection of the central nervous system. Symptoms are generally milder in children and adolescents than in adults, though severe disease does occur. A better understanding of the disease burden and duration of vaccine-mediated protection is important for vaccination recommendations.AimTo estimate TBE vaccination coverage, disease severity and vaccine effectiveness (VE) among individuals aged 0-17 years in Switzerland.MethodsVaccination coverage between 2005 and 2022 was estimated using the Swiss National Vaccination Coverage Survey (SNVCS), a nationwide, repeated cross-sectional study assessing vaccine uptake. Incidence and severity of TBE between 2005 and 2022 were determined using data from the Swiss disease surveillance system and VE was calculated using a case-control analysis, matching TBE cases with SNVCS controls.ResultsOver the study period, vaccination coverage increased substantially, from 4.8% (95% confidence interval (CI): 4.1-5.5%) to 50.1% (95% CI: 48.3-52.0%). Reported clinical symptoms in TBE cases were similar irrespective of age. Neurological involvement was less likely in incompletely (1-2 doses) and completely (≥ 3 doses) vaccinated cases compared with unvaccinated ones. For incomplete vaccination, VE was 66.2% (95% CI: 42.3-80.2), whereas VE for complete vaccination was 90.8% (95% CI: 87.7-96.4). Vaccine effectiveness remained high, 83.9% (95% CI: 69.0-91.7) up to 10 years since last vaccination.ConclusionsEven children younger than 5 years can experience severe TBE. Incomplete and complete vaccination protect against neurological manifestations of the disease. Complete vaccination offers durable protection up to 10 years against TBE.

INTRODUCTION:Switzerland has been considered free of terrestrial rabies for more than 20 years. Nevertheless, the topics of rabies and rabies vaccination are more relevant than ever. On the one hand, this is because the demand for vaccines is increasing due to the increasing mobility of humans and animals, and on the other hand, there are frequent vaccine supply shortages. Our article highlights the key points in the face of growing challenges.

Background: Travellers frequently visit popular destinations like Brazil, India, Peru, Thailand, and Tanzania, each presenting varying malaria risks. The extent to which Travellers enter high-risk malaria-endemic areas in destinations with heterogeneous malaria risk remains unclear. We used geo-location via smartphone application to(i) describe where Travellers go within countries with heterogeneous malaria risk (Brazil, India, Peru, Thailand), and (ii) compare mosquito bite prevention behaviours between these destinations and Tanzania, considered entirely high-risk for malaria. Methods: This analysis is a sub-study of the TOURIST2 cohort, which prospectively recruited1,000 travellers (>= 18 years,travelling <= 4 weeks)from Swiss travel clinics (Zurich and Basel)between09/2017-04/2019. We included734travellers to Brazil, India, Peru, Thailand, and Tanzania who provided geo-location data. Daily health and geo-location data were collected using a smartphone application. Malaria risk was categorised using2022 malaria maps from the Swiss Expert Committee for Travel Medicine. Results: Of the734 travellers, 525 travelled to Brazil, India, Peru, and Thailand, and 225 to Tanzania. InBrazil, India, Peru, and Thailand, only 2% (n=13) visited high-risk malaria areas. In Peru, 4% (n=4)visited a high-risk area; in Brazil, 3% (n=6); in Thailand, 2%when crossing the border into Myanmar(n=3); and in India, 0%. Travellers to high-risk areas were more often male (62%), slightly older (median age 42.0), and planned longer trips (median 23.0 days) than other travellers. No participants were diagnosed with malaria. Travellers to Brazil, India, Peru and Thailand used mosquito bite prevention measureless frequently than Travellers to Tanzania. Those in Tanzania had higher, but still suboptimal, use of insect spray (65% of travel-days). Conclusions: Travellers to Brazil, India, Peru, and Thailand rarely visited high-risk malaria areas, and their adherence to mosquito bite prevention measures was generally low. In Tanzania, adherence was higher but still suboptimal.

ABSTRACT Numerous clinical parameters link to severe coronavirus disease 2019, but factors that prevent symptomatic disease remain unknown. We investigated the impact of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) and endemic human coronavirus (HCoV) antibody responses on symptoms in a longitudinal children cohort ( n = 2,917) and a cross-sectional cohort including children and adults ( n = 882), all first exposed to SARS-CoV-2 (March 2020 to March 2021) in Switzerland. Saliva ( n = 4,993) and plasma ( n = 7,486) antibody reactivity to the four HCoVs (subunit S1 [S1]) and SARS-CoV-2 (S1, receptor binding domain, subunit S2 [S2], nucleocapsid protein) was determined along with neutralizing activity against SARS-CoV-2 Wuhan, Alpha, Delta, and Omicron (BA.2) in a subset of individuals. Inferred recent SARS-CoV-2 infection was associated with a strong correlation between mucosal and systemic SARS-CoV-2 anti-spike responses. Individuals with pre-existing HCoV-S1 reactivity exhibited significantly higher antibody responses to SARS-CoV-2 in both plasma (IgG regression coefficients = 0.20, 95% CI = [0.09, 0.32], P < 0.001) and saliva (IgG regression coefficient = 0.60, 95% CI = [0.088, 1.11], P = 0.025). Saliva neutralization activity was modest but surprisingly broad, retaining activity against Wuhan (median NT50 = 32.0, 1Q–3Q = [16.4, 50.2]), Alpha (median NT50 = 34.9, 1Q–3Q = [26.0, 46.6]), and Delta (median NT50 = 28.0, 1Q–3Q = [19.9, 41.7]). In line with a rapid mucosal defense triggered by cross-reactive HCoV immunity, asymptomatic individuals presented with higher pre-existing HCoV-S1 activity in plasma (IgG HKU1, odds ratio [OR] = 0.53, 95% CI = [0.29,0.97], P = 0.038) and saliva (total HCoV, OR = 0.55, 95% CI = [0.33, 0.91], P = 0.019) and higher SARS-CoV-2 reactivity in saliva (IgG S2 fold change = 1.26, 95% CI = [1.03, 1.54], P = 0.030). By investigating the systemic and mucosal immune responses to SARS-CoV-2 and HCoVs in a population without prior exposure to SARS-CoV-2 or vaccination, we identified specific antibody reactivities associated with lack of symptom development. IMPORTANCE Knowledge of the interplay between human coronavirus (HCoV) immunity and severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) infection is critical to understanding the coexistence of current endemic coronaviruses and to building knowledge potential future zoonotic coronavirus transmissions. This study, which retrospectively analyzed a large cohort of individuals first exposed to SARS-CoV-2 in Switzerland in 2020–2021, revealed several key findings. Pre-existing HCoV immunity, particularly mucosal antibody responses, played a significant role in improving SARS-CoV-2 immune response upon infection and reducing symptoms development. Mucosal neutralizing activity against SARS-CoV-2, although low in magnitude, retained activity against SARS-CoV-2 variants underlining the importance of maintaining local mucosal immunity to SARS-CoV-2. While the cross-protective effect of HCoV immunity was not sufficient to block infection by SARS-CoV-2, the present study revealed a remarkable impact on limiting symptomatic disease. These findings support the feasibility of generating pan-protective coronavirus vaccines by inducing potent mucosal immune responses.

Background: The social distancing measures associated with the COVID-19 pandemic had far reaching effects on sexual behavior worldwide. However, it remains unclear whether sexual contact with non-steady partners was a contributor to the spread of SARS-CoV-2. The aim of this study was to (i) assess whether the SARS-CoV-2 seropositivity after the first pandemic wave among people using HIV Pre-Exposure Prophylaxis (PrEP) in Zurich, Switzerland differed from that of a demographic matched population level comparison group, (ii) describe risk factors for SARS-CoV-2 seropositivity in this population, and (iii) determine whether sexual contact with non-steady partners was associated with SARS-CoV-2 seropositivity. Methods: The study was conducted between July 2020 and October 2020 as a nested cross-sectional study within two ongoing cohort studies, SwissPrEPared (all eligible PrEP users in Switzerland ≥18 years old) and Corona Immunitas (a series of cross-sectional and longitudinal studies measuring the SARS-CoV-2 seroprevalence across Switzerland, beginning in April 2020). All SwissPrEPared participants were recruited from Checkpoint Zurich (the main PrEP clinic in Zurich). Data were collected on participants’ SARS-CoV-2 antibody status, social characteristics and behavioral data after the first wave of the corona pandemic in Switzerland, and seroprevalence was compared with a propensity score-matched sample from the general Zurich population. Results: Of the 218 participants enrolled, 8.7% (n=19, 95% CI: 5.5-13.5%) were seropositive for SARS-CoV-2 during the first pandemic wave, higher than that of the general male population in Zurich aged 20-65 (5.5%, 95% CI: 3.8–8.2%). Participants on average reduced their social outings, but the seronegative were more socially active before, during, and after the first lockdown period. In a logistic model, increasing mean sexual partner count was not associated with seropositivity (OR: 0.9, 95% CI: 0.8, 1.0), but increasing number of trips abroad was associated with higher seropositivity (p=0.06, OR: 1.14, 95% CI: 1.0, 1.3). The estimated risk ratio for seropositivity for the participants compared to the general Zurich population after propensity score matching was 1.5 (95% CI: 0.53, 4.0). 94% of participants reported later receiving a COVID-19 vaccination. Discussion: Our study suggests that COVID-19 seropositivity was slightly elevated among people taking PrEP in Zurich during the first wave of the pandemic, but that socializing and sexual activity were less important than other factors in contributing to risk.

Previous mental health trajectory studies were mostly limited to the months before access to vaccination. They are not informing on whether public mental health has adapted to the pandemic. The aim of this analysis was to 1) investigate trajectories of monthly reported depressive symptoms from July 2020 to December 2021 in Switzerland, 2) compare average growth trajectories across regions with different stringency phases, and 3) explore the relative impact of self-reported worries related to health, economic and social domains as well as socio-economic indicators on growth trajectories. As part of the population-based Corona Immunitas program of regional, but harmonized, adult cohorts studying the pandemic course and impact, participants repeatedly reported online to the DASS-21 instrument on depressive symptomatology. Trajectories of depressive symptoms were estimated using a latent growth model, specified as a generalised linear mixed model. The time effect was modelled parametrically through a polynomial allowing to estimate trajectories for participants' missing time points. In all regions level and shape of the trajectories mirrored those of the KOF Stringency-Plus Index, which quantifies regional Covid-19 policy stringency. The higher level of average depression in trajectories of those expressing specific worries was most noticeable for the social domain. Younger age, female gender, and low household income went along with higher mean depression score trajectories throughout follow-up. Interventions to promote long-term resilience are an important part of pandemic preparedness, given the observed lack of an adaptation in mental health response to the pandemic even after the availability of vaccines in this high-income context.

ObjectivesBefore vaccines and effective treatments were available, quarantine of close contacts was important to limit the spread of SARS-CoV-2. To evaluate potential benefits and harms of quarantine, we aimed to estimate infection rates and describe experiences and mental health among persons in mandated quarantine during the early SARS-CoV-2 pandemic.MethodsWe invited adults in mandated quarantine after an exposure to SARS-CoV-2 identified through contact tracing of the Canton of Zurich, Switzerland, between August 2020 and January 2021. Participants completed two questionnaires and received up to two SARS-CoV-2 polymerase chain reaction tests, during and at the end of quarantine.ResultsAmong 395 participants, quarantine duration ranged from 2 to 20 days. By day 11 since the last contact, 11.1% [95% CI 8.4%–14.7%] were infected with SARS-CoV-2. The proportion of participants with symptoms of depression doubled from 9.3% before quarantine to 18.9% during quarantine, and 12.1% reported quarantine was very or extremely difficult.ConclusionAlthough quarantine was only moderately burdensome for most participants, some experienced significant difficulties and burden. Policymakers need to balance infection control with potential harms placed on individuals.

Dengue fever, endemic to most tropical and subtropical countries, is a major cause of illness in travellers, but severe dengue, hospitalisation and death are considered rare in this population. Two vaccines against dengue fever, Dengvaxia® and Qdenga®, are available. While there is no recommendation for the use of Dengvaxia® in travellers, Qdenga® has been licensed for travellers in many European countries since December 2022, most recently (29 July 2024) in Switzerland by Swissmedic. The Swiss Expert Committee for Travel Medicine (ECTM), having assessed available data on the Qdenga® vaccine, issues the following recommendations: (1) Vaccination against dengue fever virus with Qdenga® is not recommended for persons with no previous dengue fever infection. (2) Vaccination with Qdenga® may be recommended for travellers aged 6 years and older who have evidence of previous dengue infection, defined as (a) a laboratory-confirmed dengue infection (PCR, antigen or seroconversion) or (b) a compatible history of dengue infection with a positive IgG serological test AND expected exposure to a region with significant dengue transmission. Travel medicine advisors should provide clear information in accessible language on the complexity of dengue vaccines and the risk/benefit evaluation for their use in travellers.