New VLA1553 vaccine may prevent chikungunya infection: Lancet

A new study published in the Lancet by Martina Schneider and team showed that VLA1553 is a strong candidate for the prevention of chikungunya virus illness since it elicited a robust immune response and the production of seroprotective titres in nearly all of the vaccines. 

A live-attenuated vaccine option for active immunization and chikungunya virus illness prevention is VLA1553. Following immunization with VLA1553, this trial provided safety and immunogenicity data up to day 180.

43 accredited vaccination trial locations in the United States participated in this double-blind, randomized, multicentre, phase 3 study. Healthy volunteers who were at least 18 years old were eligible. VLA1553 or a placebo was given randomly (3:1) to each participant. The majority of patients having a baseline chikungunya virus antibody level that was seroprotective, as measured by a 50% plaque reduction in a micro plaque reduction neutralization test (μPRNT) with a PRNT50 titre of at least 150, 28 days after vaccination, was the main objective. Each and every person who received immunization was included in the safety analysis. At 12 pre-selected trial sites, immunogenicity studies were performed on a sample of subjects. For these subjects to be included in the per-protocol population for immunogenicity analysis, there may be no significant protocol violations. 

The key findings of this study were:

6100 persons underwent eligibility screening between September 17, 2020, and April 10, 2021. 

1971 individuals were eliminated, and 4093 participants were assigned to receive VLA1553, while 1035 received a placebo. 

Before the trial's conclusion, 358 VLA1553 participants and 133 placebo participants withdrew. 

There were 362 individuals in the per-protocol population for the immunogenicity analysis (266 in the VLA1553 group and 96 in the placebo group). 

Regardless of age, 263 (98%) of 266 individuals in the VLA1553 group developed seroprotective chikungunya virus-neutralizing antibodies 28 days after receiving a single injection of the vaccine. 

VLA1553 was usually well accepted by both younger and older individuals and had an adverse event profile similar to other licenced vaccines.

46 (1%) of the 3082 patients who received VLA1553, as well as eight (0.8%) of the 1033 participants in the placebo group, had serious side events. 

Only two severe adverse events were thought to be connected to the use of VLA1553. Both individuals made a full recovery.

Reference: 

Schneider, M., Narciso-Abraham, M., Hadl, S., McMahon, R., Toepfer, S., Fuchs, U., Hochreiter, R., Bitzer, A., Kosulin, K., Larcher-Senn, J., Mader, R., Dubischar, K., Zoihsl, O., Jaramillo, J.-C., Eder-Lingelbach, S., Buerger, V., & Wressnigg, N. (2023). Safety and immunogenicity of a single-shot live-attenuated chikungunya vaccine: a double-blind, multicentre, randomised, placebo-controlled, phase 3 trial. In The Lancet. Elsevier BV. https://doi.org/10.1016/s0140-6736(23)00641-4