[Seroepidemiology of varicella among the healthy population aged 1-19 years in Harbin, China].

OBJECTIVE: To investigate the level of IgG antibody to varicella in the healthy population aged 1-19 years in Harbin, China. METHODS: Random sampling was performed to select 1 203 healthy individuals aged 1-19 years in Harbin. According to age, they were divided into ≥1 years group (n=240), ≥4 years group (n=396), ≥7 years group (n=364) and 14-19 years group (n=203). Enzyme-linked immunosorbent assay was used to measure the concentration of varicella-zoster virus (VZV)-IgG antibody in serum, and a concentration of VZV-IgG antibody of ≥100 mIU/mL was considered positive, suggesting that the subject had the ability to resist VZV infection. RESULTS: The overall positive rate of VZV-IgG antibody was 71.49% (860/1 203), and the concentration of VZV-IgG antibody was 447±17 mIU/mL. The concentration of VZV-IgG antibody tended to increase with age (P<0.05). The positive rate of VZV-IgG antibody in the urban population was significantly higher than that in the rural population (P<0.05). There was significant difference in the positive rate of VZV-IgG antibody between the populations with different doses of varicella vaccination (P<0.05), and the population with 2 doses of vaccination had the highest positive rate of VZV-IgG antibody. There was a significant difference in the concentration of VZV-IgG antibody between the populations with different medical histories (P<0.05), and the population with a past history of varicella had the highest concentration. CONCLUSIONS: Among the healthy population aged 1-19 years in Harbin, there is a significant difference in the level of VZV-IgG antibody between the urban and rural populations, as well as between different age groups. Varicella vaccination should be strengthened in areas with a low vaccination rate and the population aged <14 years.