Towards national guidance on dengue and chikungunya vaccination in travellers: Lessons from global recommendations.

Dengue and chikungunya are mosquito-borne viral diseases with expanding geographical ranges driven by climate change, urbanisation, and globalisation. In 2024, dengue cases exceeded 14.6 million globally, with more than 12,000 deaths, while chikungunya cases surpassed 410,000 in the Americas. Increasing international mobility has resulted in a growing burden among travellers from non-endemic regions, including 126 imported dengue cases and four imported chikungunya cases in Poland in 2024. Recent approvals of Qdenga (TAK-003) for dengue and IXCHIQ (VLA1553) for chikungunya have expanded preventive options. However, implementation remains challenging because of variable efficacy, evolving safety concerns, and the absence of standardised national guidance. This review analyses vaccination recommendations issued by the WHO, ECDC, CDC, and national advisory bodies in Germany, the United Kingdom, Switzerland, France, Belgium, Canada, and the U.S. Substantial heterogeneity was identified. Most authorities recommend restricting Qdenga use in travellers to individuals with laboratory-confirmed prior dengue infection, despite broader regulatory authorisation in some jurisdictions. Use of IXCHIQ has been curtailed in several countries following reports of severe adverse events, including encephalitis and one fatal case; in August 2025 the U.S. Food and Drug Administration suspended the biologics license for IXCHIQ pending further safety evaluation. Diagnostic limitations, including flavivirus cross-reactivity and restricted access to neutralization assays, complicate vaccination decision-making. Based on this analysis, we propose tailored recommendations for Poland, prioritising vaccination of travellers with documented prior dengue infection and high exposure risk, alongside strengthened personal protective measures and pre-travel counselling. The analytical framework presented may also support policy development in other non-endemic countries.