Study on Effectiveness of 2-dose Live Attenuated Varicella Vaccine

Study on Effectiveness of 2-dose Live Attenuated Varicella Vaccine

The objective of the study is as follows:

1. To know the antibody level during different interval after received 1 dose varicella vaccine.
2. To know safety and effectiveness of received 2 doses varicella vaccine with different interval.
3. To know safety and effectiveness of received varicella vaccine and MMR at the same time.

To achieve that, this study selects children with specific varicella vaccine history, gives 1 or 2 doses varicella vaccine, collects blood specimens and makes a follow-up visit after vaccination.

All blood specimens will be tested by a third-party detection institution.

Inclusion Criteria:

• Aged 1 to 7
• Without a previous history of varicella
• With an axillary temperature ≤37.5℃ at the time of vaccination
• Appropriate varicella vaccination history
• With guardian signing the informed consent and available for clinical observation

Exclusion Criteria:

• Hypersensitive to any active substance of the vaccine including excipients and antibiotics
• With acute illness, severe or acute attack of chronic illness or fever
• With immunodeficiency or weakened immune system or being treated with immunosuppressant drugs
• Suffering a brain disease, uncontrolled epilepsy or progressive nerve system disease
• With a family or personal history of seizure, chronic illness, epilepsy or allergy
• With unknown immunization history or unable to follow the immunization schedule of EPI
• Received any vaccine within 4 weeks or willing to receive any vaccine in 1 month
• With hemorrhagic tendency or prolonged period of bleeding
• Received whole blood, plasma or immunoglobulin within 5 months
• Received systemic antibiotics or antiviral treatment for acute illness within 7 days
• With an axillary temperature ≥38℃ within 3 days
• Participating in another clinical trial
• Any situation that might influence the consequence of the clinical trial