NCT07834073

Brief Summary

This is a multicentre post-marketing cohort study to evaluate the immunogenicity and safety of a single dose of mRNA SARS-CoV-2 vaccine SYS6006 in Chinese adults predominantly with hybrid immunity. A total of 2,052 adults aged 18 years and older who received one dose of SYS6006 were monitored for serious adverse events (SAEs) for 6 months. The first 60 participants comprised an immunogenicity subgroup, with blood samples collected before vaccination and at day 14, month 3, and month 6 post-vaccination to assess humoral and cellular immune responses.

Trial Health

87
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
2,052

participants targeted

Target at P75+ for phase_4 covid19

Timeline
Completed

Started May 2023

Geographic Reach
1 country

1 active site

Status
completed

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

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Study Timeline

Key milestones and dates

Study Start

First participant enrolled

May 23, 2023

Completed
9 months until next milestone

Primary Completion

Last participant's last visit for primary outcome

February 28, 2024

Completed
Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

February 28, 2024

Completed
2.6 years until next milestone

First Submitted

Initial submission to the registry

September 17, 2026

Completed
5 days until next milestone

First Posted

Study publicly available on registry

September 22, 2026

Completed
Last Updated

September 22, 2026

Status Verified

September 1, 2026

Enrollment Period

9 months

First QC Date

September 17, 2026

Last Update Submit

September 17, 2026

Conditions

COVID-19SARS-CoV-2 Infection

Keywords

mRNA vaccineCOVID-19 vaccinesSYS6006Omicron variantHybrid immunityPost-marketing surveillanceImmunogenicitySafety

Outcome Measures

Primary Outcomes (2)

  • Geometric mean titer (GMT) of neutralizing antibodies in the immunogenicity subgroup

    Measured in the immunogenicity subgroup at 14 days after booster immunization.

    14 days after booster immunization

  • Incidence of serious adverse events (SAEs)

    Serious adverse events monitored for 6 months after the booster administration.

    Within 6 months after the booster administration

Secondary Outcomes (12)

  • Geometric mean concentration (GMC) of serum RBD-specific IgG

    Day 14 after booster immunization

  • Geometric mean concentration (GMC) of serum RBD-specific IgG

    Month 3 after booster immunization

  • Geometric mean concentration (GMC) of serum RBD-specific IgG

    Month 6 after booster immunization

  • Geometric mean concentration (GMC) of serum RBD-specific IgA

    Day 14 after booster immunization

  • Geometric mean concentration (GMC) of serum RBD-specific IgA

    Month 3 after booster immunization

  • +7 more secondary outcomes

Other Outcomes (9)

  • Antibody-dependent cellular phagocytosis (ADCP)

    Day 14 after booster immunization

  • Antibody-dependent cellular phagocytosis (ADCP)

    Month 3 after booster immunization

  • Antibody-dependent cellular phagocytosis (ADCP)

    Month 6 after booster immunization

  • +6 more other outcomes

Study Arms (1)

SYS6006 single-dose recipients

EXPERIMENTAL

Participants in this arm received a single intramuscular dose of SYS6006 (CSPC Megalith Biopharmaceutical Co., Ltd, Shijiazhuang, China), a lipid nanoparticle (LNP)-encapsulated mRNA SARS-CoV-2 vaccine containing 30 μg mRNA in 0.3 mL. The vaccine encodes the full-length spike (S) protein of the SARS-CoV-2 Omicron variant and harbours key mutations from Delta, Omicron BA.4/5 and BF.7, and was administered via intramuscular injection into the deltoid muscle of the upper arm.

Biological: SYS6006

Interventions

SYS6006BIOLOGICAL

Lipid nanoparticle (LNP)-encapsulated mRNA SARS-CoV-2 vaccine, 30 μg mRNA/0.3 mL, single intramuscular dose.

SYS6006 single-dose recipients

Eligibility Criteria

Age18 Years+
Sexall
Healthy VolunteersYes
Age GroupsAdult (18-64), Older Adult (65+)

You may qualify if:

  • Adults aged 18 years and over, including the elderly over 60 years and those with general underlying diseases.
  • At least 4 months since the last SARS-CoV-2 infection (or never infected), and at least 6 months since the last COVID-19 vaccination.
  • Able and willing to comply with the study procedures and to provide written informed consent.

You may not qualify if:

  • Suspected COVID-19 symptoms on the day of enrollment (e.g., dry/sore throat, cough).
  • Positive SARS-CoV-2 antigen rapid test at enrollment.
  • Prior receipt of the first COVID-19 booster dose .
  • History of severe adverse reactions or anaphylaxis related to vaccination, or known severe allergy to any vaccine component.
  • Pregnant or lactating women.
  • Any other condition that, in the investigator's judgment, makes the individual unsuitable for the study.

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Jiangsu Provincial Center for Disease Control and Prevention

Nanjing, China

Location

MeSH Terms

Conditions

COVID-19

Interventions

SYS6006 COVID-19 vaccine

Condition Hierarchy (Ancestors)

Pneumonia, ViralPneumoniaRespiratory Tract InfectionsInfectionsVirus DiseasesCoronavirus InfectionsCoronaviridae InfectionsNidovirales InfectionsRNA Virus InfectionsLung DiseasesRespiratory Tract Diseases

Study Design

Study Type
interventional
Phase
phase 4
Allocation
NA
Masking
NONE
Purpose
PREVENTION
Intervention Model
SINGLE GROUP
Sponsor Type
NETWORK
Responsible Party
SPONSOR

Study Record Dates

First Submitted

September 17, 2026

First Posted

September 22, 2026

Study Start

May 23, 2023

Primary Completion

February 28, 2024

Study Completion

February 28, 2024

Last Updated

September 22, 2026

Record last verified: 2026-09

Data Sharing

IPD Sharing
Will not share

Locations

CN(1)