Travel-Related Challenges of Chikungunya Virus and Vaccination Options

Chikungunya is a febrile illness caused by an arbovirus transmitted by Aedes spp. mosquitoes, which are abundant worldwide and can easily establish new habitats. With urbanization and climate change, the vector has spread to new areas. Chikungunya has caused multiple outbreaks worldwide in most continents. Molecular evidence suggests that a single mutation in the chikungunya virus can influence vector specificity, enhancing its potential to cause explosive outbreaks. The infection commonly presents with a triad of fever, rash, and arthritis. The latter symptom occurs in more than 90% of sufferers and may persist for many months to years, causing significant morbidity. Currently, no antiviral therapy is available, and management is primarily supportive. Several cases of Chikungunya acquired through international travel have been reported. Travel-associated viremic cases can drive introduction and local transmission in new geographical areas where the mosquito vector is abundant. Awareness of the disease among both travelers and healthcare providers remains poor. A global one health approach, with strengthened public health policies, enhanced surveillance, and travel-related prevention, is currently the most effective way to curb the reemerging threat of the disease. Two vaccines are currently available and are durable for at least 2 years; though they lack efficacy data, they have both been approved. First, VLA1553, trade-named IXCHIQ, is a live-attenuated vaccine with nearly 99% seroprotection; however, it has many safety concerns, including Chikungunya-like illness (CLI), and has recently been paused for use in persons older than 60 years. Second, PXVX0317, trade-named Vimkunya, is a virus-like particle with nearly 98% seroprotection, but it does not cause CLI. Both vaccines are currently recommended for travelers visiting areas with a CDC-declared outbreak.