Study on immunity duration lyophilized, attenuated live rubella vaccine

  Objective   To study the immunity duration of attenuated live rubella vaccine.

  Methods   A 5-year research on immunity duration of the lyophilized, attenuated live rubella vaccine was conducted in the children aged 8 months to 6 years in Liuyang City of Hunan Province.

  Results   The geometric mean titers(GMT)of HI antibody were 157.6 with seroconversion rate of 97.2% one month after vaccination.During the investigations period, the HI antibody declined significantly with GMT 141.2, 113.3, 67.4, 37.3 and 31.2 respectively each year, but the positive rate of HI antibody still retained at high level with a rate of 99.7%, 100.0%, 98.3%, 97.3% and 95.5% respectively.There was 4-fold HI antibody increase among 32 subjects because of asymptomatic infection, and HI antibody became negative among the 17 subjects with a accumulated rate of 9.24%.

  Conclusion   The immunity duration of the lyophilized was satisfied.