EFFICACY
IXCHIQ® demonstrated a strong seroresponse in its phase 3 clinical trial.1,2 98.9% of trial participants reached seroresponse threshold 28 days after a single dose. Seroresponse remained high at 96.3% six months post-vaccination.2
IXCHIQ® efficacy in adults aged 18 years and above2
*Defined as CHIKV neutralising antibody titre ≥ 150 by μPRNT50 (50% reduction in a micro plaque reduction neutralisation test) for baseline participants 28 days after first vaccination. The lower bound of the 95% CI for the SRR at Day 29 in IXCHIQ® group needed to exceed 70% neutralising antibody titres determined using μPRNT50 assay.2,3 Seroresponse is considered to be reasonably likely to predict protection against CHIKV.2,3 The 150 threshold was defined conservatively as a surrogate endpoint for protection and considered by both the FDA and EMA to be reasonably likely to predict clinical benefit.1,3
LASTING PROTECTION WITH IXCHIQ®
Data at 24, 36 and 48 months demonstrate that IXCHIQ® provides a long-lasting immune response after a single injection, with seroresponse rates of 96.8%, 96.6% and 94.5% respectively.1,4,5
The clinical efficacy of IXCHIQ® was assessed using a post-vaccination CHIKV-specific neutralising antibody (µPRNT50) titre threshold of ≥150. This surrogate marker for protection is referred to as seroresponse.2
SAFETY AND TOLERABILITY
IXCHIQ® was found to be generally well tolerated in a clinical trial involving more than 3,000 adults.3
Most common adverse events2
HEADACHE
32%
FATIGUE
29.4%
MYALGIA
23.7%
ARTHRALGIA
16.6%
FEVER
13.8%
NAUSEA
11.4%
ADVERSE EVENTS
Most adverse reactions were mild to moderate and were resolved in 2–3 days.3
Adverse reactions are listed according to the following frequency categories:2
- Very common: ≥1/10
- Common: ≥1/100 to ˂1/10
- Uncommon: ≥1/1000 to ˂1/100
- Rare: ≥1/10 000 to ˂1/1000
- Very rare: ˂1/10 000
*Includes: leukopenia (leukocyte decreased), neutropenia (neutrophile decreased) and lymphopenia (lymphocyte decreased).2
**Includes: Alanine aminotransferase increased (ALT) and Aspartate aminotransferase increased (AST).2
LEARN MORE ABOUT IXCHIQ®
Delve deeper into the product features, clinical findings and dosing recommendations.
IXCHIQ®▼powder and solvent for solution for injection
OVERVIEW
Get a useful overview of IXCHIQ®, including key facts about the vaccine.
IXCHIQ®▼powder and solvent for solution for injection
DOSING & ADMINISTRATION
IXCHIQ® is administered as a convenient single injectable dose.
References
- McMahon R, Toepfer S, Sattler N, et al. Antibody persistence and safety of a live-attenuated chikungunya virus vaccine up to 2 years after single-dose administration in adults in the USA: a single-arm, multicentre, phase 3b study. The Lancet Infectious Diseases. 2024;24(12):1383-1392.
- IXCHIQ®. Summary of Product Characteristics. March 2026. Available at: https://www.medicines.org.uk/emc/product/100652/smpc. Accessed: August 2026.
- Schneider M, Narciso-Abraham M, Hadl S, et al. Safety and immunogenicity of a single-shot live-attenuated chikungunya vaccine: a double-blind, multicentre, randomised, placebo-controlled, phase 3 trial. The Lancet. 2023;401(10394):2138-2147.
- GOV.UK. Chikungunya vaccine in UK travellers: JCVI advice. March 2026. Available at: https://www.gov.uk/government/publications/chikungunya-vaccine-for-uk-travellers-jcvi-advice-16-july-2025/chikungunya-vaccine-in-uk-travellers-jcvi-advice. Accessed: August 2026.
- Sattler N, Scheiblauer S, Hochreiter R, Kosulin K, Buerger V. Chikungunya virus-neutralizing antibody persistence four years after single-dose vaccination with VLA1553 (IXCHIQ®). Vaccine. 2026;88:128787.
UK-IXC-2600005 August 2026