A population-based study on the seroepidemiology of varicella zoster virus among children and adolescents in Fujian, China
Varicella continues to pose a significant public health challenge for children and adolescents in China. Although vaccination is available, the disease remains highly prevalent among children in Fujian. This study aimed to evaluate the seroepidemiology of varicella-zoster virus (VZV) and to explore the factors contributing to its high incidence in individuals aged 0–17 years. A cross-sectional serosurvey was conducted in 2023. Serum samples from 2,675 eligible individuals were tested for VZV IgG using ELISA. Demographic and vaccination data were collected via questionnaire. A total of 2,675 participants, aged between 2 days and 17 years with a median age of 6.5 years, were included. The overall seropositivity rate of VZV IgG was 47.7% (95% CI: 45.5–49.3), with a geometric mean concentration (GMC) of 81.3 mIU/mL (95% CI: 77.0–85.9). Marked variations in these immunity markers were observed across age groups, genders, and vaccination statuses. Notably, varicella vaccination coverage was substantially low: only 54.9% of children aged 1–17 years had received one dose, and merely 17.4% were fully vaccinated with two doses. A clear post-vaccination antibody waning pattern was also evident. Both seropositivity rate and GMC began to decline one year after vaccination, decreasing by more than 50% after four years. The seropositivity rates and GMC of varicella antibodies were low among individuals aged 0–17 years in Fujian Province, and vaccination coverage was insufficient, particularly for the second dose (< 20%). Antibody titers declined markedly over time, which may be partly associated with the high incidence of varicella in this region. To ensure the continuity of surveillance data, further efforts are needed to strengthen epidemiological surveillance of varicella in younger age groups and to promote the timeliness and completeness of vaccination. Not applicable.