The Food and Drug Administration (FDA) has granted Breakthrough Therapy designation to VLA1553, an investigational vaccine for protection against chikungunya disease.

Chikungunya is a mosquito-borne viral disease caused by the chikungunya virus (CHIKV), a Togaviridae virus. While the mortality rate is very low with CHIKV infection, morbidity is high with clinical symptoms that include fever, debilitating joint and muscle pain, joint swelling, headache, nausea, and rash. 

VLA1553 is a live-attenuated, single dose vaccine candidate for protection against chikungunya disease. The vaccine works by deleting a part of the chikungunya virus genome. In a phase 1 clinical trial, administration of VLA1553 resulted in 100% seroconversion of the 120 healthy participants, with antibody titers sustained after 12 months.

The Company is currently investigating the immunogenicity and safety of VLA1553 in approximately 4100 adults in a phase 3 study ( Identifier: NCT04546724). Patients will be randomly assigned 3:1 to receive a single immunization of either VLA1553 or placebo. The primary endpoint is the proportion of patients with a seroprotective CHIKV antibody level determined by µPRNT (Micro Plaque Reduction Neutralization Test) at 28 days post-vaccination. 

Juan Carlos Jaramillo, Chief Medical Officer of Valneva commented, “We are extremely pleased with FDA’s recognition of VLA1553 as a Breakthrough program. Chikungunya is a major, growing public health threat and VLA1553 targets long lasting protection against the chikungunya virus with a single shot. We will continue to work closely with the FDA to bring a preventative solution to the market as soon as possible.”


Valneva awarded FDA Breakthrough designation for its single-shot chikungunya vaccine candidate. [press release]. Saint Herblain, France: Valneva SE; July 7, 2021.