Observational Study to Assess the Effectiveness of VLA1553 Vaccine in Preventing Chikungunya During a Pilot Vaccination Strategy in Brazil

NCT07347002 | Enrolling By Invitation

• 1 other identifier: VLA1553-402
• Study Type: observational
• Target: 1,200
• Locations: 1 country
• Sites: 4

Brief Summary

This is an observational, non-interventional, test-negative case-control (TNCC) study to estimate the vaccine effectiveness of VLA1553 against Chikungunya virus in a real-world setting.

Conditions

Chikungunya Virus Infection

Outcome Measures

Primary Outcomes (1)

• Detection of CHIKV in VLA1553-vaccinated (≥14 days after vaccination) and unvaccinated study individuals with CHIKV-like symptoms confirmed by reverse transcriptase polymerase chain reaction (RT-PCR).

  Study start through study completion, an average of 23 months

Secondary Outcomes (1)

• Detection of CHIKV in VLA1553-vaccinated (≥14 days after vaccination) and unvaccinated study individuals ≥50 years of age with CHIKV-like symptoms confirmed by RT-PCR.

  Study start through study completion, an average of 23 months

Other Outcomes (4)

• Detection of CHIKV in VLA1553-vaccinated (≥14 days after vaccination) and unvaccinated individuals with CHIKV-like symptoms confirmed by RT-PCR, stratified by sex and age group (≥18 to 59 and ≥ 60 years, depending on the age group approved for the PVS)

  Study start through study completion, an average of 23 months

• Detection of CHIKV in VLA1553-vaccinated (≥14 days after vaccination) and unvaccinated study individuals with CHIKV-like symptoms confirmed by RT-PCR, stratified by time since vaccination (from 0 to 6 months after Day 15)

  Study start through study completion, an average of 23 months

• CHIKV hospitalizations (confirmed by RT-PCR) in VLA1553-vaccinated (≥14 days after vaccination) and unvaccinated study individuals; CHIKV deaths (confirmed by RT-PCR) in VLA1553-vaccinated (≥14 days after vaccination) and unvaccinated study individuals

  Study start through study completion, an average of 23 months

Study Arms (2)

Cases: Test-positive for Chikungunya virus

Biological: Live-attenuated CHIKV vaccine VLA1553

Controls: Test-negative for Chikungunya virus

Biological: Live-attenuated CHIKV vaccine VLA1553

Interventions

Live-attenuated CHIKV vaccine VLA1553 BIOLOGICAL

Non-interventional study: VLA1553 is used in the pilot vaccination strategy which is linked to this observational study.

Cases: Test-positive for Chikungunya virus; Controls: Test-negative for Chikungunya virus

Eligibility Criteria

• Age: 18 Years - 59 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)
• Sampling Method: Non-Probability Sample

Study Population

Residents of the selected areas, within the age limits approved for the PVS, presenting at the health care facilities during the study period.

You may qualify if:

• Have place of residence in a municipality where the pilot vaccination strategy is implemented;
• Are in an eligible age-group to receive the VLA1553 vaccine;
• Have been notified in SINAN as a suspected case for CHIK or Dengue surveillance during the study period;
• Have a sample registered in GAL that is collected within 0-5 days following the onset of CHIKV-like symptoms and is tested for CHIKV using RT-PCR;
• Have complete data in the Brazilian MoH databases (SINAN and GAL) on age, sex, municipality of residence, sample collection date, and date of symptom onset and the healthcare facilities where the suspected case was reported.

You may not qualify if:

• Have inconclusive RT-PCR result for CHIKV;
• Have the first CHIKV-like symptom onset less than 14 days from date of vaccination.

Sponsors & Collaborators

• Valneva Austria GmbH: lead
• Coalition for Epidemic Preparedness Innovations: collaborator
• Butantan Foundation: collaborator

Study Sites (4)

Universidade Federal Do Ceará

Fortaleza, Ceará, 60430-160, Brazil

Location

Universidade Federal de Minas Gerais, CT Terapias Avançadas e Inovadoras

Belo Horizonte, Minas Gerais, 31270-901, Brazil

Location

Centro de Pesquisas Clínicas Universidade Federal Sergipe, Hospital e Maternidade São João de Deus

Laranjeiras, Sergipe, 49060-025, Brazil

Location

Fundação Faculdade Regional De Medicina De São José Do Rio Preto

São Pedro, São Paulo, 15090-000, Brazil

Location

MeSH Terms

Conditions

Chikungunya Fever

Condition Hierarchy (Ancestors)

Alphavirus Infections; Arbovirus Infections; Vector Borne Diseases; Infections; Mosquito-Borne Diseases; Virus Diseases; Togaviridae Infections; RNA Virus Infections

Study Design

• Study Type: observational
• Observational Model: CASE CONTROL
• Time Perspective: RETROSPECTIVE
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: December 4, 2025
• First Posted: January 16, 2026
• Study Start: February 2, 2026
• Primary Completion (Estimated): December 31, 2027
• Study Completion (Estimated): December 31, 2027
• Last Updated: February 11, 2026

Record last verified: 2026-02

Locations

BR (4)