Trial · NCT04546724

Pivotal Study to Evaluate Safety and Immunogenicity of a Live-Attenuated Chikungunya Virus Vaccine Candidate in Adults

NCT04546724, Phase 3, Completed, Valneva Austria GmbH; results first posted 2022-07-25

3 sourcestrials-2026-11-12-0.5.0

Cite this record

ConductScience Library. Pivotal Study to Evaluate Safety and Immunogenicity of a Live-Attenuated Chikungunya Virus Vaccine Candidate in Adults. Trials, record NCT04546724. Release trials-2026-11-12-0.5.0, 12 Nov 2026. https://conductscience.org/library/trials/NCT04546724

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Trial

As registered on ClinicalTrials.gov, in the graph's capture of the registry.

Title: Pivotal Study to Evaluate Safety and Immunogenicity of a Live-Attenuated Chikungunya Virus Vaccine Candidate in Adults
NCT number: NCT04546724
Status: Completed
Phases: Phase 3
Enrollment: 4,128 participants, actual
Lead sponsor: Valneva Austria GmbH
Conditions: Chikungunya Virus Infection
Interventions: VLA1553, Placebo
First posted: 2020-09-14
Last updated: 2023-06-28
Results first posted: 2022-07-25

Source ClinicalTrials.gov

Registered outcomes15

Each outcome the trial registered, primary first, in ClinicalTrials.gov's words.

List	Outcome	Time frame	Description
Primary	Number of Participants With a Seroprotective CHIKV Antibody Level for Baseline Negative Subjects 28 Days Post-vaccination	on Day 29 after single vaccination	Seroprotection rate, based on a surrogate of protection agreed with FDA Assay used for analysis was based on µPRNT (Micro Plaque Reduction Neutralization Test). Participants at pre-selected sites were included, if they had available Day 1 and Day 29 samples and without major protocol deviations that could impact the immune response.
Secondary	CHIKV-specific Neutralizing Antibody Titers	Until Day 180	CHIKV-specific Neutralizing Antibody Titers on Day 8, and Day 29 Postvaccination as Determined by μPRNT ( (Micro Plaque Reduction Neutralization Test) Assay
Secondary	Number of Participants With Seroprotective CHIKV Antibody Level	Until Day 180	Seroprotection rate, based on a surrogate of protection agreed with FDA Seroprotective CHIKV Antibody Level Defined as μPRNT (Micro Plaque Reduction Neutralization Test) for Baseline Negative Subjects
Secondary	Number of Participants With Seroconversion	Until Day 180	Seroconversion was defined as CHIKV-specific neutralizing antibody titer of ≥ 20 based on µPRNT (Micro Plaque Reduction Neutralization Test) for baseline negative subjects
Secondary	Fold "Change" of CHIKV-specific Neutralizing Antibody Titers Compared to Baseline	until Day 180	Fold Change of CHIKV-specific Neutralizing Antibody Titers Determined by μPRNT ( (Micro Plaque Reduction Neutralization Test) as compared to baseline
Secondary	Number of Participants Reaching an X-fold Change in CHICKV-specific Neutralizing Antibody Titer Compared to Baseline	until Day 180	Number of Participants Reaching an at Least 4-fold, 8-fold, 16-fold or 64-fold change of CHIKV-specific Neutralizing Antibody Titers Determined by μPRNT ( (Micro Plaque Reduction Neutralization Test) as compared to baseline
Secondary	Unsolicited AEs	Until Day 29	Number of Participants with Unsolicited Adverse Events
Secondary	Solicited Injection Site AEs	within 10 days post-vaccination	Number of Participants with solicited injection site reactions
Secondary	Solicited Systemic AEs	within 10 days post-vaccination	Number of Participants with solicited systemic reactions
Secondary	Adverse Events	until Day 180	Number of Participants with any Adverse Events

1 to 10 of 15Source ClinicalTrials.gov

See all 15 registered outcomes

Outcomes15

Each outcome the trial posted results for, in ClinicalTrials.gov's words.

Type	Outcome	Time frame	Population	Units	Measured as
PRIMARY	Number of Participants With a Seroprotective CHIKV Antibody Level for Baseline Negative Subjects 28 Days Post-vaccination	on Day 29 after single vaccination	The Per-Protocol population used for immunogenicity analyses, is based on participants without major protocol deviations that could impact the immune response.	Participants	COUNT_OF_PARTICIPANTS
SECONDARY	CHIKV-specific Neutralizing Antibody Titers	Until Day 180	The Per-Protocol population used for immunogenicity analyses, is based on participants without major protocol deviations that could impact the immune response.	Antibody Titers	GEOMETRIC_MEAN
SECONDARY	Number of Participants With Seroprotective CHIKV Antibody Level	Until Day 180	The Per-Protocol population used for immunogenicity analyses, is based on participants without major protocol deviations (PDs) that could impact the immune response.~Counts of participants per time point vary: baseline AND post-line µPRNT result are needed at a given timepoint; results for a specific timepoint were excluded in case of major PD (e.g., major time window deviation resulted in exclusion of a result for a given visit/ time point, results from earlier/ later visits were included)	Participants	COUNT_OF_PARTICIPANTS
SECONDARY	Number of Participants With Seroconversion	Until Day 180	The Per-Protocol population used for immunogenicity analyses, is based on participants without major protocol deviations that could impact the immune response.	Participants	COUNT_OF_PARTICIPANTS
SECONDARY	Fold Change of CHIKV-specific Neutralizing Antibody Titers Compared to Baseline	until Day 180	The Per-Protocol population used for immunogenicity analyses, is based on participants without major protocol deviations that could impact the immune response.	fold increase	MEAN
SECONDARY	Number of Participants Reaching an X-fold Change in CHICKV-specific Neutralizing Antibody Titer Compared to Baseline	until Day 180	The Per-Protocol population used for immunogenicity analyses, is based on participants without major protocol deviations that could impact the immune response.	Participants	COUNT_OF_PARTICIPANTS
SECONDARY	Unsolicited AEs	Until Day 29		Participants	COUNT_OF_PARTICIPANTS
SECONDARY	Solicited Injection Site AEs	within 10 days post-vaccination		Participants	COUNT_OF_PARTICIPANTS
SECONDARY	Solicited Systemic AEs	within 10 days post-vaccination		Participants	COUNT_OF_PARTICIPANTS
SECONDARY	Adverse Events	until Day 180		Participants	COUNT_OF_PARTICIPANTS

1 to 10 of 15Source ClinicalTrials.gov

See all 15 outcomes

Results by group128

Each measurement the trial posted, group by group, in the words and numbers it posted.

Outcome	Group	Category	Value	Spread	Units
Number of Participants With a Seroprotective CHIKV Antibody Level for Baseline Negative Subjects 28 Days Post-vaccination	VLA1553 18-64 Years		204		Participants
Number of Participants With a Seroprotective CHIKV Antibody Level for Baseline Negative Subjects 28 Days Post-vaccination	Placebo 18-64 Years		0		Participants
Number of Participants With a Seroprotective CHIKV Antibody Level for Baseline Negative Subjects 28 Days Post-vaccination	VLA1553 ≥65 Years		59		Participants
Number of Participants With a Seroprotective CHIKV Antibody Level for Baseline Negative Subjects 28 Days Post-vaccination	Placebo ≥65 Years		0		Participants
CHIKV-specific Neutralizing Antibody Titers	VLA1553 18-64 Years	Visit 2 - Day 8	13.6	95% Confidence Interval 12.22 to 15.23	Antibody Titers
CHIKV-specific Neutralizing Antibody Titers	Placebo 18-64 Years	Visit 2 - Day 8	10.2	95% Confidence Interval 9.92 to 10.50	Antibody Titers
CHIKV-specific Neutralizing Antibody Titers	VLA1553 ≥65 Years	Visit 2 - Day 8	13.4	95% Confidence Interval 11.05 to 16.31	Antibody Titers
CHIKV-specific Neutralizing Antibody Titers	Placebo ≥65 Years	Visit 2 - Day 8	10.0	95% Confidence Interval 10.0 to 10.0	Antibody Titers
CHIKV-specific Neutralizing Antibody Titers	VLA1553 18-64 Years	Visit 3 - Day 29	3273.7	95% Confidence Interval 2860.93 to 3746.04	Antibody Titers
CHIKV-specific Neutralizing Antibody Titers	Placebo 18-64 Years	Visit 3 - Day 29	10.1	95% Confidence Interval 9.89 to 10.33	Antibody Titers

1 to 10 of 128Source ClinicalTrials.gov

See all 128 results by group

Participant flow6

How many started, completed or left each group, period by period.

Period	Milestone	Group	Participants
Overall Study	STARTED	VLA1553	3,082
Overall Study	STARTED	Placebo	1,033
Overall Study	COMPLETED	VLA1553	2,724
Overall Study	COMPLETED	Placebo	920
Overall Study	NOT COMPLETED	VLA1553	358
Overall Study	NOT COMPLETED	Placebo	113

Source ClinicalTrials.gov

Adverse events164

Each adverse event the trial posted, group by group: the participants affected out of those at risk.

Type	Event	Organ system	Group	Affected	At risk	Events
other	Headache	Nervous system disorders	VLA1553	986	3,082	1,028
other	Headache	Nervous system disorders	Placebo	160	1,033	178
other	Fatigue	General disorders	VLA1553	886	3,082	893
other	Fatigue	General disorders	Placebo	137	1,033	139
other	Myalgia	Musculoskeletal and connective tissue disorders	VLA1553	750	3,082	758
other	Myalgia	Musculoskeletal and connective tissue disorders	Placebo	82	1,033	84
other	Arthralgia	Musculoskeletal and connective tissue disorders	VLA1553	554	3,082	589
other	Arthralgia	Musculoskeletal and connective tissue disorders	Placebo	63	1,033	70
other	Injection site pain	General disorders	VLA1553	413	3,082	519
other	Injection site pain	General disorders	Placebo	101	1,033	122

1 to 10 of 164Source ClinicalTrials.gov

See all 164 adverse events

Adverse event totals6

The totals the trial posted for each group.

Total	Group	Affected	At risk
Total, all-cause mortality	VLA1553	2	3,082
Total, all-cause mortality	Placebo	1	1,033
Total, other adverse events	VLA1553	1,721	3,082
Total, other adverse events	Placebo	373	1,033
Total, serious adverse events	VLA1553	46	3,082
Total, serious adverse events	Placebo	8	1,033

Source ClinicalTrials.gov

Papers2

The papers the trial lists on ClinicalTrials.gov.

PMID	Listed as	Source
37321235	DERIVED	PubMed
39998495	DERIVED	PubMed

Grants0

The grants NIH RePORTER links to the trial, newest funded first: NIH's, and some of AHRQ's, CDC's, FDA's and VA's. Each shows its title, principal investigators, organization and funder in its newest year.

None in this release.

Trial comparisons8

Comparisons of the trial's two groups, calculated by ConductScience from the counts it posted.

Comparison	Source
VLA1553 vs Placebo: Serious Adverse Event	Trial comparisons
VLA1553 vs Placebo: Related Adverse Event of Special Interest	Trial comparisons
VLA1553 vs Placebo: Related Serious Adverse Event	Trial comparisons
VLA1553 vs Placebo: Unsolicited AEs	Trial comparisons
VLA1553 vs Placebo: Related Adverse Events	Trial comparisons
VLA1553 vs Placebo: Adverse Event of Special Interest	Trial comparisons
VLA1553 vs Placebo: deaths from any cause	Trial comparisons
VLA1553 vs Placebo: serious adverse events	Trial comparisons

Tests0

The ConductCognition tests this trial's registered outcomes name, as ScienceGraph matched them in trial-tests-2026-11-12-0.2.1.

None in this release.

Data dates

The day each source was copied for this release.

ClinicalTrials.gov: 2026-11-12; ClinicalTrials.gov
Results, from AACT: 2026-03-23; AACT
NIH grant links: 2026-11-13; NIH RePORTER

Sources 3

ClinicalTrials.gov's posted results, through CTTI's AACTFreely available. Acknowledgement requested
ClinicalTrials.govNo license stated
NIH RePORTER's clinical studies and project filesPublic domain

Each source's terms

ClinicalTrials.gov's posted results, through CTTI's AACTClinicalTrials.gov data via Aggregate Analysis of ClinicalTrials.gov (AACT), CTTI. CTTI makes its materials freely available and requests acknowledgement. https://aact.ctti-clinicaltrials.org/documentation/299
ClinicalTrials.govnone stated
NIH RePORTER's clinical studies and project filesPublic domain (NIH RePORTER)

ClinicalTrials.gov's data carry an international copyright outside the United States: https://clinicaltrials.gov/about-site/terms-conditions.

For software

Read this trial from software.

The record and each of its lists are JSON, twenty rows a page. No key.

GET https://conductscience.org/api/trials/v1/NCT04546724

GET https://conductscience.org/api/trials/v1/NCT04546724/results?page=2

API reference For AI assistants