A Phase 1/2 interventional study of Influenza Vaccine (Split Virion), Inactivated, Quadrivalent, ZFA02 Adjuvant (low dose) and Influenza Vaccine (Split Virion), Inactivated, Quadrivalent, ZFA02 Adjuvant placebo (low dose) in Influenza, Human, sponsored by Anhui Zhifei Longcom Biologic Pharmacy Co., Ltd.. Recruiting at 1 site in China. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-05-05.
Sponsored by Anhui Zhifei Longcom Biologic Pharmacy Co., Ltd. (part of Chongqing Zhifei Biological Products Co., Ltd.) · Phase 1/2, Interventional, and Prevention
This clinical trial adopts a seamless design of phase I/II, conducted in two stages: phase I and phase II. Phase I is the age/dose ramp up stage, and phase II is the dose expansion stage.The purpose of this clinical trial is to evaluate the safety and tolerability of different doses of Influenza Vaccine (Split Virion), Inactivated, Quadrivalent, ZFA02 Adjuvant，explore the immunogenicity of the vaccine, and determine the appropriate dose for later clinical trials of this product.
Overall design:
Adopting a randomized, blinded research design. This experiment adopts a seamless connection design of Phase I/II, conducted in two stages: Phase I and Phase II. Phase I is the age/dose escalation stage, and Phase II is the dose extension stage.
Age/dose escalation stage: A randomized, blinded, placebo-controlled study design was used. 120 subjects were enrolled in the study, in order of age from 18 to 49 years old to 50 years old and above, from low dose to high dose. They were divided into four cohorts, with 30 subjects in each cohort (including 20 who received high-dose or low-dose experimental vaccines and 10 who received placebo). The first 6 subjects in each cohort were assigned to be sentinel group, and the researchers reviewed the safety data of the sentinel group within 7 days after vaccination. After confirming safety (not meeting the criteria for suspending/terminating the trial), the remaining 24 subjects in the cohort were enrolled.
Dose expansion stage: A randomized, blinded, positive controlled study design was used. 500 subjects were enrolled, divided into two age groups: 18-49 years old and 50 years old and above. 250 subjects were enrolled in each age group and randomly divided into low-dose group, high-dose group, and positive control group according to a 2:2:1 ratio. The proportion of people aged 60 and above in the population aged 50 and above shall not be less than 80%, and the proportion of people aged 70 and above shall not be less than 30%.
2,356 studies on the registry are indexed under Influenza, Human; 184 are open to participants now.
This study's planned enrollment of 620 is above the median of 227 across 1,957 interventional studies indexed under Influenza, Human.
Browse Influenza, Human studies →Anhui Zhifei Longcom Biologic Pharmacy Co., Ltd. is the lead sponsor of 49 studies on the registry; 4 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
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.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Vaccines made with a weakened form of the germ, such as measles–mumps–rubella (MMR), chickenpox and yellow fever. They can be risky when the immune system is weakened. Flu injections are not live; the nasal flu spray is.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
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.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Autoimmune disease
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Live vaccines
Vaccines made with a weakened form of the germ, such as measles–mumps–rubella (MMR), chickenpox and yellow fever. They can be risky when the immune system is weakened. Flu injections are not live; the nasal flu spray is.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
20 subjects aged 18-49 were enrolled and randomly assigned to the low-dose experimental group, and received one dose of the low-dose experimental vaccine.
Biological: Influenza Vaccine (Split Virion), Inactivated, Quadrivalent, ZFA02 Adjuvant (low dose)
10 subjects aged 18-49 were enrolled and randomly assigned to the low-dose placebo group, and received one dose of the low-dose placebo.
Biological: Influenza Vaccine (Split Virion), Inactivated, Quadrivalent, ZFA02 Adjuvant placebo (low dose)
20 subjects aged 18-49 were enrolled and randomly assigned to the high-dose experimental group, and received one dose of the high-dose experimental vaccine.
Biological: Influenza Vaccine (Split Virion), Inactivated, Quadrivalent, ZFA02 Adjuvant (high dose)
10 subjects aged 18-49 were enrolled and randomly assigned to the high-dose placebo group, and received one dose of the high-dose placebo.
Biological: Influenza Vaccine (Split Virion), Inactivated, Quadrivalent, ZFA02 Adjuvant placebo (high dose)
20 subjects aged 50 and above were enrolled and randomly assigned to the low-dose experimental group, and received one dose of the low-dose experimental vaccine.
Biological: Influenza Vaccine (Split Virion), Inactivated, Quadrivalent, ZFA02 Adjuvant (low dose)
10 subjects aged 50 and above were enrolled and randomly assigned to the low-dose placebo group, and received one dose of the low-dose placebo.
Biological: Influenza Vaccine (Split Virion), Inactivated, Quadrivalent, ZFA02 Adjuvant placebo (low dose)
20 subjects aged 50 and above were enrolled and randomly assigned to the high-dose experimental group, and received one dose of the high-dose experimental vaccine.
Biological: Influenza Vaccine (Split Virion), Inactivated, Quadrivalent, ZFA02 Adjuvant (high dose)
10 subjects aged 50 and above were enrolled and randomly assigned to the high-dose placebo group, and received one dose of the high-dose placebo.
Biological: Influenza Vaccine (Split Virion), Inactivated, Quadrivalent, ZFA02 Adjuvant placebo (high dose)
100 subjects aged 18-49 were enrolled and randomly assigned to the low-dose experimental group, and received one dose of the low-dose experimental vaccine.
Biological: Influenza Vaccine (Split Virion), Inactivated, Quadrivalent, ZFA02 Adjuvant (low dose)
100 subjects aged 18-49 were enrolled and randomly assigned to the high-dose experimental group, and received one dose of the high-dose experimental vaccine.
Biological: Influenza Vaccine (Split Virion), Inactivated, Quadrivalent, ZFA02 Adjuvant (high dose)
50 subjects aged 18-49 were enrolled and randomly assigned to the positive control group, and received one dose of the positive control vaccine.
Biological: Influenza Vaccine (Split Virion), Inactivated, Quadrivalent
100 subjects aged 50 and above were enrolled and randomly assigned to the low-dose experimental group, and received one dose of the low-dose experimental vaccine.
Biological: Influenza Vaccine (Split Virion), Inactivated, Quadrivalent, ZFA02 Adjuvant (low dose)
100 subjects aged 50 and above were enrolled and randomly assigned to the high-dose experimental group, and received one dose of the high-dose experimental vaccine.
Biological: Influenza Vaccine (Split Virion), Inactivated, Quadrivalent, ZFA02 Adjuvant (high dose)
50 subjects aged 50 and above were enrolled and randomly assigned to the positive control group, and received one dose of the positive control vaccine.
Biological: Influenza Vaccine (Split Virion), Inactivated, Quadrivalent
Inject 1 dose of low-dose vaccine
Inject 1 dose of low-dose placebo
Inject 1 dose of high-dose vaccine
Inject 1 dose of high-dose placebo
Inject 1 dose of positive control vaccine
AE occurren
Number and incidence of all adverse events
Time frame: within 30 days after vaccination
AESI occurrences
Number and incidence of all adverse events of special interest
Time frame: within 30 days after vaccination
SAE occurrences
Number and incidence of all serious adverse events
Time frame: within 12 months after vaccination
Serum alanine aminotransferase level
All participants in Phase I were tested for alanine aminotransferase levels before and on the 4th day after vaccination
Time frame: on the 4th day after vaccination
Serum aspartate transaminase level
All participants in Phase I were tested for aspartate transaminase levels before and on the 4th day after vaccination
Time frame: on the 4th day after vaccination
Serum total bilirubin level
All participants in Phase I were tested for total bilirubin levels before and on the 4th day after vaccination
Time frame: on the 4th day after vaccination
Serum white blood cell level
All participants in Phase I were tested for white blood cell levels before and on the 4th day after vaccination
Time frame: on the 4th day after vaccination
Serum platelet level
All participants in Phase I were tested for platelet levels before and on the 4th day after vaccination
Time frame: on the 4th day after vaccination
Serum hemoglobin level
All participants in Phase I were tested for hemoglobin levels before and on the 4th day after vaccination
Time frame: on the 4th day after vaccination
Urinary protein level in urine
All participants in Phase I were tested for urinary protein levels in urine before and on the 4th day after vaccination
Time frame: on the 4th day after vaccination
Urinary red blood cell level in urine
All participants in Phase I were tested for urinary red blood cell levels in urine before and on the 4th day after vaccination
Time frame: on the 4th day after vaccination
Serum antibody level
Detect the levels of hemagglutination inhibition (HI) antibodies against influenza viruses H1N1, H3N2, and type B (B/Victoria and B/Yamagata).
Time frame: 30 days after vaccination
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Anhui Zhifei Longcom Biologic Pharmacy Co., Ltd. →