Tropical Diseases, Travel Medicine and Vaccines最新文献

Background: Cameroon introduced the RTS, S/AS01 malaria vaccine into routine expanded immunisation (EPI) in 2024, targeting 42 priority health districts. We assessed changes in total malaria burden between intervention and non-intervention districts over 2023-2025.

Methods: We conducted a retrospective, quasi-experimental, ecological longitudinal study using a difference-in-differences (DiD) approach on routine district-level surveillance data from 206 districts (42 intervention, 164 non-intervention) for 2023-2025. Outcomes included severe malaria rate (per 1,000 children < 5), uncomplicated malaria rate, all malaria-related hospitalisations, and malaria mortality rate (per 100,000). Crude pre-post changes and DiD were calculated. Adjusted linear DiD models with district and year fixed effects and cluster-robust standard errors were also fitted. Subgroup analyses examined interactions with seasonal malaria chemoprevention (SMC), intermittent preventive treatment in infants (IPTi), insecticide-treated nets (ITNs), and ecological region.

Results: Baseline characteristics differed significantly: intervention districts had higher ITN coverage (60.2% vs. 45.5%, p = 0.006), higher IPT coverage (35.1% vs. 24.4%, p = 0.001), and larger populations (median 121,284 vs. 89,592, p = 0.029). From 2023 to 2025, intervention districts experienced larger declines in all outcomes. Crude DiD showed a 2.6 per 1000 (15%) reduction in severe malaria, 8.1 per 1000 (22%) reduction in uncomplicated malaria, 5.3 per 1000 (28%) reduction in hospitalisations, and 4.1 per 100,000 (26%) reduction in malaria deaths. Adjusted linear DiD estimates were not statistically significant (e.g., severe malaria coefficient - 0.54, 95% CI - 11.07 to 9.99, p = 0.920). Subgroup analyses indicated the largest effects in the Sahel (crude rate ratio 0.78) and added benefit when the vaccine was combined with SMC (additional - 5.6 per 1000 reduction). In 2025 alone, vaccination averted an estimated 7,200 severe cases, 12,800 uncomplicated cases, 5,300 hospitalisations, and 77 deaths.

Conclusion: Crude trends show favourable declines in malaria burden in intervention districts, but adjusted estimates were null, likely due to selection bias and low power. These findings support continued vaccine scale-up and use of routine data for monitoring, while acknowledging the limitations of non-randomised evaluations.

The substantial number of older adults undertaking international travel has increased the relevance of pre-travel prevention in this population. However, vaccination strategies in this group require consideration of immune aging, baseline status, medication use, and travel-related exposure. This narrative review summarizes the current evidence on vaccination in senior travelers, with particular attention to the vaccines most relevant to this population, the differences in the strength of evidence across vaccines, and the clinical factors that should guide pre-travel decision-making. Routine vaccines, including influenza, COVID-19, pneumococcal, respiratory syncytial virus, herpes zoster, and tetanus-diphtheria vaccines, constitute an essential part of pre-travel assessment, whereas travel-specific vaccines, such as hepatitis A, hepatitis B, typhoid, rabies, Japanese encephalitis, tick-borne encephalitis, and cholera, should be considered according to the destination, itinerary, expected exposure, and time before departure. Yellow fever vaccination represents a particular clinical challenge because advancing age is associated with a greater risk of serious vaccine-associated adverse events, making individualized risk‒benefit assessment essential. Recently introduced dengue and chikungunya vaccines should also be considered on an individualized basis, taking into account exposure risk, potential benefits, comorbidities, and the current limitations of the available evidence. The review also highlights the importance of integrating vaccination with non-vaccine preventive strategies, including food and water precautions, vector avoidance, and hygiene measures. Although the evidence base has expanded, important uncertainties remain, particularly because age-specific data are limited and frail older adults remain underrepresented in clinical studies. Overall, pre-travel care for senior travelers should be comprehensive, exposure-based, and individualized according to the clinical profile and travel characteristics of each traveler.

Background: The Hajj and Arbaeen walk pilgrimages are significant religious mass gatherings (MGs) among Muslims. Respiratory tract infections (RTIs) remain a major concern during such events. This study aimed to evaluate the prevalence of respiratory viral infections among Iranian pilgrims during the 2025 Hajj and Arbaeen walk.

Methods: Throat swabs were collected from 110 symptomatic Iranian pilgrims returning from these MGs. Molecular techniques were used to detect respiratory viruses.

Results: A total of 60 Hajj pilgrims and 50 Arbaeen walk pilgrims, with an age range 8 to 82 years for the combined groups, participated. Rhinovirus was the most common virus detected among symptomatic pilgrims in both MGs. Notably, the rate of SARS-CoV-2 infection was 1.7% in Hajj pilgrims and 32% in Arbaeen pilgrims. Co-infections of rhinovirus and SARS-CoV-2 were identified in 8% of Arbaeen pilgrims. Additionally, coronavirus OC43/HKU1, influenza A (H3N2), and influenza B virus were detected at low frequencies. No cases of MERS-CoV were found among the 2025 Hajj pilgrims.

Conclusion: These findings provide preliminary data on the circulation of respiratory viruses during religious MGs in 2025. Continued surveillance is essential to reduce respiratory infection risks during such mass gatherings.

Respiratory Syncytial Virus (RSV) is a formidable respiratory pathogen that particularly affects infants and children. RSV presents with diverse clinical severity, most often causing mild upper airway symptoms but sometimes progressing to severe and potentially fatal lower respiratory tract disease. This virus has a major global public health impact and places a substantial strain on healthcare systems. RSV exhibits distinct seasonal trends that vary across geographic locations and climate zones, and recognizing these patterns and their determinants is essential for policymakers to schedule RSV immunization programs effectively. Increasing attention has been directed toward the evolving landscape of RSV vaccines, particularly regarding their potential to prevent infection and reduce disease severity, especially among vulnerable populations. Until now, three RSV vaccines, Arexvy, Abrysvo, and mRESVIA, have received approval from the FDA. In addition, monoclonal antibodies such as Nirsevimab and Clesrovimab prevent severe RSV disease and are recommended for infants. Given the significant global impact of RSV, this narrative review addresses its multifaceted aspects, including epidemiology and global impact, clinical manifestations, therapeutic strategies, vaccine development, and its emerging potential as an oncolytic agent.

Background: Rabies post-exposure prophylaxis (PEP) using anti-rabies vaccine and immunoglobulin is widely recognized as highly effective. However, individuals who receive PEP are typically deferred from blood donation for a full year, largely due to theoretical concerns about transfusion safety. However, the evidence supporting such a prolonged deferral remains limited.

Objectives: This study aimed to assess rabies real-time RT-PCR status and serological responses among PEP recipients at various intervals following treatment and to consider whether these findings might justify a re-examination of the current one-year blood donor deferral policy after anti-rabies treatment.

Methods: We conducted a single-center interventional study at an anti-rabies clinic in a tertiary hospital in North India. The study enrolled twenty immunologically naïve adults who had sustained category III animal bites, with no prior rabies exposure or treatment, and who adhered fully to the protocol. Participants received anti-rabies vaccines and equine rabies immunoglobulin as appropriate for their category. Follow-up samples were collected between as early as 48 days and 120 days after the bites. These samples were tested for rabies viral RNA using real-time RT-PCR (Geno-Sens Rabies Real-Time PCR Kit), and antibody titers were measured using ELISA (Rabies Platelia Kit II). Data analysis included descriptive statistics, percentile analysis, correlation analysis, and regression analysis, as appropriate.

Results: In this cohort, dogs were responsible for 90% of bites, with 85% of incidents being unprovoked and 65% involving lower limbs. All participants tested negative using RT-PCR. ELISA titers ranged from 0.881 to 4.449 IU/mL, and all participants exceeded the protective threshold of 0.5 IU/mL. The mean titer was 2.97 ± 1.04 IU/mL.

Conclusion: The lack of detectable rabies viral RNA, together with sustained protective antibody titers, indicates an effective response to PEP in this group. These findings support a more evidence-based reconsideration of the current prolonged blood donor deferral following anti-rabies treatment.

The convergence of infectious disease outbreaks, climate shocks, and conflict is exposing fundamental limitations in existing global health preparedness systems, which remain largely fragmented and disease-specific. Epidemics increasingly occur within multi-layered emergencies, where overlapping risks interact to overwhelm fragile health systems and complicate response efforts. This perspective examines structural gaps in current preparedness approaches, including siloed financing, limited integration of multi-sectoral intelligence, and constrained institutional autonomy. Drawing on a structured policy analysis of publicly available literature and institutional experiences, particularly from the Africa Centres for Disease Control and Prevention (Africa CDC), the analysis highlights how integrated epidemic intelligence and regional coordination can support more anticipatory and context-responsive preparedness. Africa CDC's evolving architecture illustrates the potential of combining surveillance data across health, environmental, and mobility domains to inform earlier and more targeted interventions. Building on these insights, this perspective proposes an intelligence-led solidarity model that integrates equitable resource allocation, interoperable regional intelligence, and predictable financing as interdependent components of resilient preparedness systems. Such an approach repositions preparedness as a shared global public good, emphasizing alignment between data, resources, and governance structures. In the context of increasingly complex and concurrent crises, an intelligence-led solidarity framework offers a pathway to strengthen global health security by enabling more coordinated, adaptive, and forward-looking responses.

Background: Hepatitis B virus (HBV) infection remains a major public health challenge in sub-Saharan Africa despite the availability of a safe and effective vaccine. In Nigeria, adult vaccination coverage and completion rates are not well characterized within hospital-based populations.

Methods: A hospital-based cross-sectional study was conducted among 1,200 adults attending Federal Medical Centre (FMC) Keffi, Nasarawa State, Nigeria. Data on socio-demographics, HBV-related knowledge, attitudes, perceived barriers, vaccination uptake, and completion were collected using a structured questionnaire. Knowledge and attitude scores were categorized into poor, fair, and good levels. Associations between socio-demographic characteristics and vaccination uptake were examined using chi-square and Fisher's exact tests, with statistical significance set at p < 0.05.

Results: The mean age of respondents was predominantly 36-40 years (32.5%), with males constituting 72.3%. Most respondents had tertiary education (91.8%) and were civil servants (83.4%). Overall awareness of HBV was high (95.5%), with a mean knowledge score of 12.37 ± 1.42. Good knowledge was observed in 74.2% of respondents, while 57.2% demonstrated good attitudes toward HBV prevention. Vaccination uptake was high, with 93.5% reporting receipt of at least one vaccine dose. However, only 22.3% had completed the recommended three-dose schedule, while 48.2% and 23.1% had received one and two doses, respectively. Willingness to complete vaccination was reported by 81.6% of respondents. Perceived barriers included high vaccine cost (72.4%), inadequate access to health facilities (96.9%), fear of side effects (71.9%), and insufficient information (73.5%). No significant associations were found between socio-demographic variables and vaccination uptake (p > 0.05 for all).

Conclusion: Despite high HBV vaccination initiation and knowledge levels, substantial gaps in vaccine completion persist. Addressing financial, informational, and access-related barriers is essential to improve full vaccination coverage among Nigerian adults.

Artificial intelligence (AI) is increasingly influencing travel medicine, a field traditionally reliant on expert judgement and static guidelines. Machine learning systems, generative AI models and digital surveillance tools have the potential to enhance pre-travel counselling, improve diagnostic pathways and strengthen outbreak detection. However, concerns remain regarding variable performance, data privacy and the absence of clear regulatory frameworks. This Perspective examines the role of AI across the travel health continuum, highlighting both opportunities and limitations. Rather than replacing clinical expertise, AI should be carefully validated and integrated to support decision-making. Responsible implementation could improve access, personalize care and strengthen global health security.

Background: Rwanda reported its first Marburg virus disease (MVD) outbreak in September 2024. This study presents an assessment of Rwanda's National Reference Laboratory Operational Capacity during the 2024 Marburg Virus Disease Outbreak Response.

Methods: The assessment was conducted using the World Health Organization laboratory assessment tool for viral haemorrhagic fever (VHF) diagnostic capacity. This was complemented by an evaluation of various laboratory quality indicators like the turnaround time (TAT). Data were collected through direct observation, documents' review, and interviews with laboratory staff. Descriptive analysis of key response activities and observations was conducted using Microsoft Office (Excel). Also, the map of testing sites was drawn using QGIS 3.40.0 software.

Results: The NRL's response to the MVD outbreak achieved an overall score of 98%. All components scored 100% except for the quality of the laboratory system, which scored 89% due to the lack of External Quality Assessment (EQA) for MVD. Key achievements during the outbreak response included (i) reduction in the turnaround time (TAT) from sample reception to releasing results from 24 to 7 h, (ii) the recruitment of more laboratory staff supporting sample collection, transportation, testing and results reporting, (ii) creation of five new MVD testing sites, (iii) training of laboratory staff, (iv) digitalization of the laboratory flow, and (v) establishing a 24/7 telephone line for easy communication with laboratories on MVD suspected samples being processed.

Conclusion: The strong performance of the NRL highlights its robust laboratory system, which allowed effective testing of MVD suspected cases. We recommend implementing an EQA scheme for VHF diagnostics in Rwanda, including the MVD. Also, improving measures for biosafety, biosecurity, and infection prevention and control in all health facilities would reduce the risk of such infections in the future.

We report an imported case of co-infection with fascioliasis and schistosomiasis in a 37-year-old patient with no known medical history, originally from Djibouti, a country in sub-Saharan East Africa. The diagnosis was confirmed by the detection of Schistosoma ova, suggestive clinical symptoms, positive serologies to both fascioliasis and schistosomiasis, and the atypical appearance of hepatic lesions on MRI. The patient was in France as a tourist. He was treated with a dual therapy of triclabendazole and praziquantel. His clinical condition improved without treatment-related side effects. This case highlights the necessity to search for these two parasitic infections in the presence of suggestive liver involvement, particularly in case of epidemiological risk.