Immunogenicity and Safety of Diphtheria, Tetanus, Pertussis (DTaP) Vaccine in 3-month-old Infants

This is a Phase III, Single Center, Randomized, Blind, and Positive Control Clinical Trial conducted in Guangxi Province, China. The purpose of this study is to evaluate the safety and immunogenicity of Diphtheria, Tetanus and Acellular Pertussis (Component) Combined Vaccine (Adsorbed) in 3-month-old infants. Expected to include 1584 3-month-old infants. Among them, 1056 infants were randomly assigned to the experimental group and active control group 1, and 528 infants were included in active control group 2. Select the top 200 subjects with study numbers from the experimental group as immunological persistence follow-up subset.

Inclusion criteria

• Basic immune stage:

• 3-month-old infants who can provide valid identification documents;
• Infants should be born following a 37-42 weeks of pregnancy and have a birth weight that meets the standard (2500g ≤ body weight ≤ 4500g);
• The legal guardian of the subject voluntarily agrees to their child's participation in the trial and signs a written informed consent form;
• The legal guardian of the subject has the ability to understand the trial procedure and participate in all planned follow-up visits;
• Has not received a vaccine containing the active ingredients of pertussis, diphtheria, tetanus combined vaccine;
• Active control group 2 has not been vaccinated with any vaccine containing the active ingredients of poliomyelitis vaccine or haemophilus influenzae vaccine;
• Enhanced immunity stage:

• Infants and young children aged 18-24 months who have been enrolled in this clinical trial at the age of 3 months;
• Basic immunization has been completed in this clinical trial;
• According to the researcher's opinion, the subjects and their legal guardians are able to comply with the requirements of the clinical trial protocol.

Exclusion criteria

• Basic immune stage:

• Has a history of pertussis, diphtheria, or tetanus;
• Has any history of severe allergies to vaccination in the past;
• Allergy to any component of the experimental vaccine;
• Has a history or family history of epilepsy, convulsions, encephalopathy, mental illness;
• Individuals with thrombocytopenia, any coagulation dysfunction, or undergoing anticoagulant therapy that may cause contraindications for subcutaneous injection;
• Suffering from serious congenital malformations or serious diseases that may interfere with the conduct or completion of the trial including but not limited to: infant wheezing, Down syndrome, severe thalassemia, heart disease, liver disease, kidney disease, diabetes, hereditary allergies, Guillain Barre syndrome, severe skin diseases, congenital or acquired immune defects (repeated perianal abscess), etc;
• Has the history of severe abnormal production process, suffocation rescue, neurological damage, and current pathological jaundice;
• Suffering from infectious diseases with clinical or serological evidence, such as tuberculosis, hepatitis B, hepatitis C, or HIV infection confirmed by parents;
• Within 3 months before to enrollment, has received systemic corticosteroid treatment (any route of administration, ≥ 2mg/kg/day) for ≥ 14 days, such as prednisone, inhaled steroids such as budesonide, and fluticasone; Or being using other immunosuppressants such as cyclosporine, tacrolimus, etc. before enrollment;
• Within 3 months before enrollment，has received treatment with immunoglobulin and/or any blood products (except hepatitis B immunoglobulin) ;
• Participating in or planning to participate in clinical trials of other drugs in the near future;
• According to the researcher's judgment, there are any other factors that are not suitable for the subjects to participate in the clinical trial.
• Enhanced immunity stage:

• Newly discovered severe allergic history to any previous vaccination;
• Individuals with thrombocytopenia, any coagulation dysfunction, or undergoing anticoagulant therapy that may cause contraindications for subcutaneous injection;
• Suffering from serious congenital malformations or serious diseases that may interfere with the conduct or completion of the test, including but not limited to: infant wheezing, Down syndrome, severe thalassemia, heart disease, liver disease, kidney disease, diabetes, hereditary allergies, Guillain Barre syndrome, severe skin diseases, congenital or acquired immune defects (repeated perianal abscess), etc;
• After completing basic immunization, subjects were vaccinated with other vaccine containing the active ingredients of pertussis, diphtheria, tetanus combined vaccine before booster immunization;
• Participating in or planning to participate in clinical trials of other drugs in the near future;
• According to the researcher's judgment, there are any other factors that are not suitable for the subjects to participate in the clinical trial.