Analysis of antibody dynamics in Chinese children aged 1-3 years after single-dose varicella vaccination: A 42 months prospective study

• Main Authors: Xiang Sun (Author), Lei Zhang (Author), Zhiguo Wang (Author), Wen Wang (Author)
• Format: Book
• Published: Taylor & Francis Group, 2024-12-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.
• Notes: 10.1080/21645515.2024.2410065; 2164-554X; 2164-5515
• Keywords: Varicella vaccine; prospective study; restricted cubic spline; waning immunity; vaccination strategy; Immunologic diseases. Allergy; RC581-607; Therapeutics. Pharmacology; RM1-950
• Source: Human Vaccines & Immunotherapeutics, Vol 20, Iss 1 (2024)

In China, children aged 12 months receive only a single dose of the varicella vaccine and the incidence of varicella remains high. This study aims to evaluate the changes in immunity among children aged 1-3 years following a single dose of the varicella vaccine, providing a scientific basis for determining the optimal age for a second vaccination. This prospective cohort study employed glycoprotein enzyme-linked immunosorbent assay (gpELISA) for antibody detection. The changes in IgG antibody levels over time post-vaccination were analyzed using a restricted cubic spline (RCS) fitted binary logistic regression model. Varicella surveillance data were collected from the National Notifiable Disease Reporting System (NNDRS). Following a peak in varicella incidence in 2019, the incidence shifted toward older age groups. The cohort study results revealed a seropositivity rate of 100% in children during the 18 months post-vaccination, which subsequently declined to 71.6% by the 42 months. The geometric mean concentration (GMC) decreased from 307.6mIU/mL to 115.2mIU/mL. Additionally, 14 children contracted varicella during the follow-up period, resulting in a breakthrough rate of 2.85%. RCS analysis indicated that antibody levels fell below the protective threshold 18.69 months post-vaccination, with a non-linear decline in the odds ratio(OR) of maintaining antibody concentrations ≥ 50mIU/mL(p < .001, Pnonlinear ≤ 0.001). This study demonstrates that the long-term protective efficacy of a single dose of the varicella vaccine diminishes over time in children, underscoring the necessity of implementing a two-dose vaccination strategy. The findings provide scientific evidence for determining the optimal timing for administering the second dose of the vaccine.