About this trial
This study consists of two parts. Part 1 is a retrospective cohort study and part 2 is a prospective cohort study. In Part 1 ,the scaled logit model was used to assess the correlation between varicella-zoster virus (VZV) antibody titers using fluorescent-antibody-to-membrane-antigen assay (FAMA) 30 days after varicella vaccine immunization and the risk of subsequent varicella breakout/disease , to determine the protective threshold for achieving FAMA antibodies. Part 2 was to validate the model in part 1.
Eligibility criteria
Qualifiers
1-12 years children who were the siblings or children of the indicator varicella cases, or the deskmates/roommates of the indicator varicella cases;
Having close contacts with the indicator varicella cases at least 2 days during the period from 5 days before the onset and 2 days after the onset;
Without varicella vaccination history or having varicella vaccination history (the last dose of varicella was manufacured by Sinovac, with an interval of >30 days before enrollment)
Subjects/legal guardian can understand and sign the informed consent;
Disqualifiers
Without varicella history;
Body temperature ≥37.0℃ on the day of enrollment, or skin rash on the head, torso, and limbs;
Having any confirmed or suspected immunodeficiency disorder, including tumor patients undergoing chemotherapy, human immunodeficiency virus (HIV) infection, continuous use of steroid hormones for more than 30 days (prednisone equivalent ≥2mg/kg days in children), or having other immunosuppressive disorder as determined by the clinician;
The investigators considered that participation in this study was not appropriate for various other reasons.
Trial design
Treatments tested in this trial
- Varicella vaccine