A Phase 4 interventional study of Anflu® and Vaxigrip® in Influenza, sponsored by Sinovac Biotech Co., Ltd. Not yet recruiting at 6 sites in China. Open to female participants aged 18 Years to 45 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-09-21.
Sponsored by Sinovac Biotech Co., Ltd · Phase 4, Interventional, and Prevention
A phase IV clinical trial of Influenza Vaccine (Split Virion), Inactivated (Anflu®) developed by Sinovac Biotech Co., Ltd will be conducted in pregnant women.
A total of 150 healthy pregnant women aged 18\~45 years at 22 to 34 weeks (+6 days) of pregnancy will be enrolled. All participants will be randomized to test group and control group in a ratio of 2:1 and receive one dose of vaccine (0.5 mL) of Sinovac Influenza Vaccine (Split Virion) , Inactivated (Anflu®) or Sanofi VAXIGRIP®, respectively.
A phase IV clinical trial of Influenza Vaccine (Split Virion), Inactivated (Anflu®) developed by Sinovac Biotech Co., Ltd will be conducted in Chinese pregnant women.
A total of 150 healthy pregnant women aged 18\~45 years at 22 to 34 weeks (+6 days) of pregnancy will be enrolled.The trial is a randomized, double-blind, positive controlled study to evaluate the immunogenicity and safety of Influenza Vaccine (Split Virion) ,Inactivated (Anflu®) manufactured by Sinovac. The active control vaccine is VAXIGRIP® manufactured by Sanofi.
For immunogenicity assessment, blood samples will be collected from participants prior to vaccination, 28 days post-vaccination, and at the end of pregnancy (at delivery) to evaluate antibody levels in pregnant women following influenza vaccination. Additionally, the cord blood samples will be collected at delivery to assess transplacental antibody transfer to the fetus. Antibodies will be tested using the hemagglutination-inhibition (HI) assay.
For safety assessment, any immediate adverse events within 30 minutes after vaccine administration, solicited local and systemic adverse events within 7 days and unsolicited adverse events within 28 days will be collected. Serious adverse events will be collected from the time of informed consent signature until 3 months after delivery (or until 3 months after the event if pregnancy termination occurs). Pregnancy and neonatal outcomes will be collected by medical record review .
2,356 studies on the registry are indexed under Influenza, Human; 184 are open to participants now.
This study's planned enrollment of 150 is below the median of 227 across 1,957 interventional studies indexed under Influenza, Human.
Browse Influenza, Human studies →Sinovac Biotech Co., Ltd is the lead sponsor of 93 studies on the registry; 19 are open to participants now.
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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.
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.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
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.
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.
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.
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.
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
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.
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.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
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.
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.
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.
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.
ALT and AST (liver enzymes)
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ULN (upper limit of normal)
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Bilirubin
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
100 participants will receive one dose of vaccine (0.5 mL) of Sinovac Influenza Vaccine (Split Virion) Inactivated (Anflu®) . Route of administration is intramuscular injection at deltoid muscle of upper arm.Immunization schedule is 1 dose
Biological: Anflu®
50 participants will receive one dose of vaccine (0.5 mL) of VAXIGRIP® manufactured by Sanofi. Route of administration is intramuscular injection at deltoid muscle of upper arm.Immunization schedule is 1 dose
Biological: Vaxigrip®
Participants will receive one dose of Sinovac Anflu® .
Participants will receive one dose of Sanofi Vaxigrip®.
The seroconversion rates (SCRs) of hemagglutination inhibition (HI) antibodies at day 28 ,as measured by HAI assay for vaccine-matched influenza A and B
Influenza A included H1N1 and H3N2 and influenza B strains included Victoria-lineage. Seroconversion is defined as either a baseline HI titer \<1:10 and a post-vaccination titer ≥1:40 or a baseline HI titer ≥1:10 and a minimum 4-fold rise in post-vaccination HI antibody titer.
Time frame: 28 days after vaccination
Incidence of adverse reactions within 28 days after vaccination
Incidence of adverse reactions within 28 days after vaccination. Adverse reactions include solicited and unsolicited adverse reactions. Solicited local (injection site) symptoms: pain, swelling, erythema, induration, pruritus; Solicited systemic (non-injection site) symptoms: fever (axillary temperature), fatigue, myalgia, headache, hypersensitivity reaction.
Time frame: 28 days after vaccination
The seroprotection rates (SPRs) of HI antibodies at day 28 ,as measured by HAI assay for vaccine-matched influenza A and B
Influenza A included H1N1 and H3N2 and influenza B strains included Victoria-lineage. Seroprotection is defined as an HI titer ≥1: 40.
Time frame: 28 days after vaccination
The geometric mean titers (GMTs) of HI antibodies at day 28 ,as measured by HAI assay for vaccine-matched influenza A and B
Influenza A included H1N1 and H3N2 and influenza B strains included Victoria-lineage. Log-transformed post-vaccination HI antibody titer will be the dependent variable, with treatment group as fixed effect and log-transformed pre-vaccination HI antibody titer as covariate. Least-squares mean differences with two-sided 95% CIs will be estimated and back-transformed via exponentiation to derive adjusted GMT ratios (experimental vs control) and corresponding two-sided 95% CIs.
Time frame: 28 days after vaccination
The geometric mean fold rises (GMFRs) of HI antibodies at day 28 ,as measured by HAI assay for vaccine-matched influenza A and B
Influenza A included H1N1 and H3N2 and influenza B strains included Victoria-lineage. Geometric mean of antibody fold-rise with two-sided 95% CI will be calculated , along with the geometric mean ratio and its corresponding two-sided 95% CI.
Time frame: 28 days after vaccination
The SCRs of HI antibodies at delivery, as measured by HAI assay for vaccine-matched influenza A and B
Influenza A included H1N1 and H3N2 and influenza B strains included Victoria-lineage. Seroconversion is defined as either a baseline HI titer \<1:10 and a post-vaccination titer ≥1:40 or a baseline HI titer ≥1:10 and a minimum 4-fold rise in post-vaccination HI antibody titer.
Time frame: At the date of delivery , estimated to be 6-18 weeks after randomization.
The SPRs of HI antibodies at delivery ,as measured by HAI assay for vaccine-matched influenza A and B
Influenza A included H1N1 and H3N2 and influenza B strains included Victoria-lineage. Seroprotection is defined as an HI titer ≥1: 40.
Time frame: At the date of delivery , estimated to be 6-18 weeks after randomization.
The GMTs of HI antibodies at delivery,as measured by HAI assay for vaccine-matched influenza A and B
Influenza A included H1N1 and H3N2 and influenza B strains included Victoria-lineage. Log-transformed post-vaccination HI antibody titer will be the dependent variable, with treatment group as fixed effect and log-transformed pre-vaccination HI antibody titer as covariate. Least-squares mean differences with two-sided 95% CIs will be estimated and back-transformed via exponentiation to derive adjusted GMT ratios (experimental vs control) and corresponding two-sided 95% CIs.
Time frame: At the date of delivery , estimated to be 6-18 weeks after randomization.
The GMFRs of HI antibodies at delivery,as measured by HAI assay for vaccine-matched influenza A and B
Influenza A included H1N1 and H3N2 and influenza B strains included Victoria-lineage. Geometric mean of antibody fold-rise with two-sided 95% CI will be calculated , along with the geometric mean ratio and its corresponding two-sided 95% CI.
Time frame: At the date of delivery , estimated to be 6-18 weeks after randomization.
The SPRs of HI antibodies in cord blood at delivery ,as measured by HAI assay for vaccine-matched influenza A and B
Influenza A included H1N1 and H3N2 and influenza B strains included Victoria-lineage. Seroprotection is defined as an HI titer ≥1: 40.
Time frame: At the date of delivery, estimated to be 6-18 weeks after randomization
The GMTs of HI antibodies in cord blood at delivery, as measured by HAI assay for vaccine-matched influenza A and B
Influenza A included H1N1 and H3N2 and influenza B strains included Victoria-lineage. Log-transformed post-vaccination HI antibody titer will be the dependent variable, with treatment group as fixed effect and log-transformed pre-vaccination HI antibody titer as covariate. Least-squares mean differences with two-sided 95% CIs will be estimated and back-transformed via exponentiation to derive adjusted GMT ratios (experimental vs control) and corresponding two-sided 95% CIs.
Time frame: At the date of delivery, estimated to be 6-18 weeks after randomization
Incidence of serious adverse events from vaccination through 3 months after delivery.
Serious adverse events within 3 months after delivery.
Time frame: From vaccination to 3 months after delivery.
Pregnancy outcomes
Pregnancy outcomes: term birth, preterm birth, elective termination of pregnancy, fetal death, and gestational complications, etc.
Time frame: At the date of delivery, estimated to be 6-18 weeks after randomization
Neonatal birth outcomes
Birth outcomes: normal status, low birth weight, congenital malformations, neonatal NICU admission, and neonatal death, etc.
Time frame: 3 months after delivery
This study is not yet recruiting, as verified in Aug 2026. You cannot join it, but the record below documents what was studied.
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