Immunogenicity data

Strong and robust seroresponse rates (SRRs) demonstrated in a pivotal study1,2

IXCHIQ induced a seroresponse in 98.9% of participants 28 days after a single dose1,2

SRR, %

  • 100
  • 75
  • 50
  • 25
  • 00
    Placebo Icon
  • 98.9
    Placebo Icon
  • 98.6
    Placebo Icon
  • 100
    Placebo Icon
Day 29
  • Placebo: All (N=96)

  • IXCHIQ: All (N=266)

  • IXCHIQ: 18-64 years (n=207)

  • IXCHIQ: ≥65 years (n=59)

High SRRs were sustained post vaccination1,2

98.9 %

1 month post vaccination

96.3 %

6 months post vaccination

No overall difference in effectiveness was observed between
participants 65 years of age and older and younger participants1

Data from a pivotal, multicenter, randomized, placebo-controlled, double-blind, phase 3 trial evaluating the immunogenicity and safety of IXCHIQ in adults ≥18 years of age (n=4,115). Immunogenicity data are based on a subset of the first 501 enrolled participants at 12 preselected study sites across the United States, representative of the whole study population.1,2

The primary immunogenicity endpoint was seroresponse rate, the proportion of participants with CHIKV neutralizing antibody titers ≥150 determined by µPRNT50 for baseline negative participants 28 days post vaccination.1,2

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References: 1. IXCHIQ. Prescribing information. Valneva USA Inc.; 2023. 2. 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. Lancet. 2023;401(10394):2138-2147.


IXCHIQ is a vaccine indicated for the prevention of disease caused by chikungunya virus (CHIKV) in individuals 18 years of age and older who are at increased risk of exposure to CHIKV.

This indication is approved under accelerated approval based on anti-CHIKV neutralizing antibody levels. Continued approval for this indication may be contingent upon verification and description of clinical benefit in confirmatory studies.


ContraindicationsDo not administer IXCHIQ to individuals who are immunodeficient or immunosuppressed due to disease or medical therapy (e.g., from hematologic and solid tumors, receipt of chemotherapy, congenital immunodeficiency, long-term immunosuppressive therapy or patients with HIV infection who are severely immunocompromised), or to individuals with a history of a severe allergic reaction to any component of the vaccine.

Warnings and PrecautionsAppropriate medical treatment used to manage immediate allergic reactions must be available in the event an acute anaphylactic reaction occurs following administration of IXCHIQ.

Vaccination with IXCHIQ may cause severe or prolonged chikungunya-like adverse reactions. Severe chikungunya-like adverse reactions that prevented daily activity and/or required medical intervention occurred in 1.6% of 3,082 IXCHIQ recipients and no placebo recipients. Fourteen IXCHIQ recipients had prolonged (duration at least 30 days) chikungunya-like adverse reactions.

Potential for vertical transmission of vaccine virus and fetal/neonatal adverse reactions. Vertical transmission of wild-type CHIKV from pregnant individuals with viremia at delivery is common and can cause potentially fatal CHIKV disease in neonates. It is not known if the vaccine virus can be vertically transmitted and cause fetal or neonatal adverse reactions. Decisions to administer IXCHIQ during pregnancy should take into consideration the individual’s risk of exposure to wild-type CHIKV, gestational age, and risks to the fetus or neonate from vertical transmission of wild-type CHIKV.

Syncope can occur with administration of IXCHIQ. Procedures should be in place to avoid injury from fainting.

IXCHIQ may not protect all individuals who receive the vaccine.

Adverse Reactions In clinical studies, the most common injection site reaction (>10%) was tenderness (11%). The most common systemic adverse reactions (>10%) were headache (32%), fatigue (29%), myalgia (24%), arthralgia (17%), fever (14%), and nausea (11%).

Use in Specific Populations PregnancyThere is a pregnancy registry to monitor outcomes in women exposed to IXCHIQ during pregnancy and it may be reached by contacting OXON Epidemiology at 1-855-417-6214. There are no adequate and well-controlled studies of IXCHIQ in pregnant individuals, and human data available from clinical trials with IXCHIQ are insufficient to establish the presence or absence of vaccine-associated risk during pregnancy.

To report SUSPECTED ADVERSE REACTIONS, contact Valneva at 1-844-349-4276 or VAERS at 1-800-822-7967 or

Please click here to see full Prescribing Information.