Historic Development in Disease Prevention
The United States Food and Drug Administration (FDA) is close to approving a groundbreaking vaccine for chikungunya, a debilitating mosquito-borne illness. This approval, expected next month, represents a pivotal moment in combating a disease that affects over half the world’s countries. Scott Weaver, a virologist at the University of Texas Medical Branch, hailed this as “great news,” given the almost two decades of research in developing a chikungunya vaccine.
Valneva’s Pioneering Vaccine
French pharmaceutical company Valneva has spearheaded the vaccine’s development. Initially, the vaccine will likely be recommended for U.S. travelers, but broader approval is anticipated, which could significantly impact countries most affected by the disease.
First identified in 1952 in Tanzania, chikungunya—named from the Kimakonde language, meaning “disease that bends up the joints”—is rarely fatal but causes severe, lasting joint pain in up to 40% of those infected. The disease thrives in warm climates, where Aedes aegypti and A. albopictus mosquitoes are prevalent.
A Novel Approach to Vaccine Development
The chikungunya vaccine consists of a laboratory-weakened virus that is safe and doesn’t cause illness. Remarkably, the FDA is considering approval without standard efficacy data from human trials, as traditional phase 3 trials were deemed unfeasible due to the rapid spread of the virus. Instead, Valneva demonstrated that 99% of recipients developed robust, long-lasting antibodies against the virus.
Post-approval, the FDA will require Valneva to conduct a comprehensive human study to confirm real-world efficacy. This requirement underscores the commitment to ensuring the vaccine’s effectiveness against chikungunya in diverse populations.
The Journey to Approval
The path to this vaccine’s approval was lengthy and fraught with challenges. Earlier attempts, including one by the U.S. Army over five decades ago, stalled due to limited perceived need and sporadic disease outbreaks. However, significant outbreaks in recent years across various continents have spurred renewed urgency in vaccine development.
Global Impact and Future Plans
Last week, a CDC advisory committee recommended prioritizing the vaccine for U.S. adults traveling to countries experiencing outbreaks. The potential military application is also under consideration, given the virus’s ability to significantly impact troop readiness.
Looking beyond the U.S., collaborations are underway to make the vaccine accessible and affordable in middle- and low-income countries, particularly in regions like Brazil and Paraguay, which have witnessed the majority of chikungunya cases this year. Valneva’s representative suggested a possible price point of $10 to $20 per dose in these areas, markedly lower than the estimated $350 per dose for U.S. travelers.
The Role of Climate Change
The advent of the chikungunya vaccine comes at a critical time, as climate change alters mosquito habitats and patterns, potentially increasing the reach of vector-borne diseases like chikungunya. With mosquito populations moving northward in Europe, local outbreaks in countries like Italy, Spain, and France highlight the growing need for effective vaccines.