A Phase 4 interventional study of SYS6006 in COVID-19 and SARS-CoV-2 Infection, sponsored by Jiangsu Province Centers for Disease Control and Prevention. Completed at 1 site in China. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-09-22.
Sponsored by Jiangsu Province Centers for Disease Control and Prevention · Phase 4, Interventional, and Prevention
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.
This study evaluated the immunogenicity and safety of a single dose of the mRNA SARS-CoV-2 vaccine SYS6006 (CSPC Megalith Biopharmaceutical Co., Ltd, Shijiazhuang, China) in Chinese adults aged 18 years and older predominantly with hybrid immunity against COVID-19. Between May and August 2023, 2,052 adults in five cities of Jiangsu Province, China (Taizhou, Changzhou, Lianyungang, Suqian, and Wuxi) received one intramuscular dose of SYS6006 (30 μg mRNA/0.3 mL) and were followed for 6 months to monitor serious adverse events (SAEs). The first 60 participants comprised the immunogenicity subgroup; serum and peripheral blood mononuclear cells (PBMCs) were collected before vaccination and at day 14, month 3, and month 6 post-vaccination. Immunogenicity assessments included pseudovirus neutralizing antibody geometric mean titres (GMTs) against wild-type (WT), BA.4/5, and XBB.1.16; receptor-binding domain (RBD)-specific IgG and IgA; ACE2-RBD binding inhibition; Fc-mediated effector functions (ADCP, ADCC, ADNP); and IFN-γ/IL-2 ELISpot responses.
7,990 studies on the registry are indexed under COVID-19; 466 are open to participants now.
This study's enrollment of 2,052 is above the median of 102 across 4,364 interventional studies indexed under COVID-19.
Browse COVID-19 studies →Jiangsu Province Centers for Disease Control and Prevention is the lead sponsor of 77 studies on the registry; 5 are open to participants now.
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Exclusion Criteria:
Any other condition that, in the investigator's judgment, makes the individual unsuitable for the study.
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Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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
Lipid nanoparticle (LNP)-encapsulated mRNA SARS-CoV-2 vaccine, 30 μg mRNA/0.3 mL, single intramuscular dose.
Geometric mean titer (GMT) of neutralizing antibodies in the immunogenicity subgroup
Measured in the immunogenicity subgroup at 14 days after booster immunization.
Time frame: 14 days after booster immunization
Incidence of serious adverse events (SAEs)
Serious adverse events monitored for 6 months after the booster administration.
Time frame: Within 6 months after the booster administration
Geometric mean concentration (GMC) of serum RBD-specific IgG
GMC of serum RBD-specific IgG antibodies against WT and Omicron variants, measured by ELISA after booster immunization
Time frame: Day 14 after booster immunization
Geometric mean concentration (GMC) of serum RBD-specific IgG
GMC of serum RBD-specific IgG antibodies against WT and Omicron variants, measured by ELISA after booster immunization
Time frame: Month 3 after booster immunization
Geometric mean concentration (GMC) of serum RBD-specific IgG
GMC of serum RBD-specific IgG antibodies against WT and Omicron variants, measured by ELISA after booster immunization
Time frame: Month 6 after booster immunization
Geometric mean concentration (GMC) of serum RBD-specific IgA
GMC of serum RBD-specific IgA antibodies against WT and Omicron variants, measured by ELISA after booster immunization
Time frame: Day 14 after booster immunization
Geometric mean concentration (GMC) of serum RBD-specific IgA
GMC of serum RBD-specific IgA antibodies against WT and Omicron variants, measured by ELISA after booster immunization
Time frame: Month 3 after booster immunization
Geometric mean concentration (GMC) of serum RBD-specific IgA
GMC of serum RBD-specific IgA antibodies against WT and Omicron variants, measured by ELISA after booster immunization
Time frame: Month 6 after booster immunization
ACE2-RBD binding inhibition rate
Rate of inhibition of ACE2-RBD binding in serum, measured by surrogate virus neutralization / competitive binding assay after booster immunization.
Time frame: Day 14 after booster immunization
ACE2-RBD binding inhibition rate
Rate of inhibition of ACE2-RBD binding in serum, measured by surrogate virus neutralization / competitive binding assay after booster immunization.
Time frame: Month 3 after booster immunization
ACE2-RBD binding inhibition rate
Rate of inhibition of ACE2-RBD binding in serum, measured by surrogate virus neutralization / competitive binding assay after booster immunization.
Time frame: Month 6 after booster immunization
Antigen-specific T-cell response measured by ELISpot
Frequency of antigen-specific T cells (spot-forming cells) in peripheral blood measured by ELISpot assay after booster immunization.
Time frame: Day 14 after booster immunization
Antigen-specific T-cell response measured by ELISpot
Frequency of antigen-specific T cells (spot-forming cells) in peripheral blood measured by ELISpot assay after booster immunization.
Time frame: Month 3 after booster immunization
Antigen-specific T-cell response measured by ELISpot
Frequency of antigen-specific T cells (spot-forming cells) in peripheral blood measured by ELISpot assay after booster immunization.
Time frame: Month 6 after booster immunization
Antibody-dependent cellular phagocytosis (ADCP)
ADCP activity induced by booster immunization against WT and Omicron variants, measured by bead-based phagocytosis assay.
Time frame: Day 14 after booster immunization
Antibody-dependent cellular phagocytosis (ADCP)
ADCP activity induced by booster immunization against WT and Omicron variants, measured by bead-based phagocytosis assay.
Time frame: Month 3 after booster immunization
Antibody-dependent cellular phagocytosis (ADCP)
ADCP activity induced by booster immunization against WT and Omicron variants, measured by bead-based phagocytosis assay.
Time frame: Month 6 after booster immunization
Antibody-dependent neutrophil phagocytosis (ADNP)
ADNP activity induced by booster immunization against WT and Omicron variants, measured by neutrophil-based phagocytosis assay.
Time frame: Day 14 after booster immunization
Antibody-dependent neutrophil phagocytosis (ADNP)
ADNP activity induced by booster immunization against WT and Omicron variants, measured by neutrophil-based phagocytosis assay.
Time frame: Month 3 after booster immunization
Antibody-dependent neutrophil phagocytosis (ADNP)
ADNP activity induced by booster immunization against WT and Omicron variants, measured by neutrophil-based phagocytosis assay.
Time frame: Month 6 after booster immunization
Antibody-dependent cellular cytotoxicity (ADCC)
ADCC activity induced by booster immunization against WT and Omicron variants, measured by reporter/effector-cell assay.
Time frame: Day 14 after booster immunization
Antibody-dependent cellular cytotoxicity (ADCC)
ADCC activity induced by booster immunization against WT and Omicron variants, measured by reporter/effector-cell assay.
Time frame: Month 3 after booster immunization
Antibody-dependent cellular cytotoxicity (ADCC)
ADCC activity induced by booster immunization against WT and Omicron variants, measured by reporter/effector-cell assay.
Time frame: Month 6 after booster immunization
Plan to share: No
No publications or documents are linked to this record.
Ran from May 2023 to primary completion in Feb 2024, 9 months.
Of 145 non-industry phase 4 interventional studies under COVID-19, half reached primary completion within 9 months of starting (the median), counting those still running; a quarter within 5 and three quarters within 19. This study's 9 months is close to that.
Counting every sponsor, half of 188 studies reached it within 8 months; a quarter within 4 and three quarters within 16.
How these figures are worked out, and which studies are left out of them.
This study is completed, as verified in Sep 2026. You cannot join it, but the record below documents what was studied.
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Studies of the drug tested here: SYS6006 COVID-19 vaccine
Jiangsu Province Centers for Disease Control and Prevention