北京市二价脊髓灰质炎减毒活疫苗引入前后不同基础免疫程序效果和疫苗效价分析

Immunogenicity of primary poliovirus vaccination schedules before and after introduction of bivalent oral poliovirus vaccine in Beijing

目的了解二价脊髓灰质炎(脊灰)减毒活疫苗(b OPV)引入前后北京市2014年和2016年不同基础免疫程序免疫效果和疫苗效价。方法 2014年和2016年脊灰疫苗基础免疫程序分别为3剂三价脊灰减毒活疫苗(t OPV)全程免疫和1剂脊灰灭活疫苗(IPV)与2剂二价脊灰减毒活疫苗(b OPV)序贯免疫,分别在北京市两个区选择完成基础免疫后4-8周的婴儿,采集血标本以检测脊灰病毒中和抗体,同时采集不同疫苗储运环节的疫苗标本以检测疫苗效价。结果 2014年和2016年分别调查儿童72人和68人。2014年基础免疫后Ⅰ、Ⅲ型脊灰病毒中和抗体阳性率分别为98.61%和100%,抗体滴度(1∶)[中位数(四分位数间距)]分别为1 536(1 024-1 536)、1 536(512-1 536);2016年基础免疫后Ⅰ型、Ⅲ型脊灰病毒中和抗体阳性率均为100%,抗体滴度(1∶)分别为1 024(512-1 536)、1 536(1 024-1 536)。2014年和2016年Ⅰ、Ⅲ型脊灰病毒中和抗体分布均有显著性差异(Ⅰ型:χ2=8.77,P=0.038;Ⅲ型:χ2=16.76,P=0.001)。2014年t OPV的平均效价为6.1±0.1Lg CCID50/剂,2016年b OPV的平均效价为6.9±0.2Lg CCID50/剂(t=-7.76,P<0.001)。结论新疫苗b OPV引入后,IPV-b OPV序贯免疫程序的基础免疫效果与引入前的t OPV全程和IPV-t OPV序贯免疫程序效果一样好;疫苗储运各环节疫苗效价均合格,冷链运转良好。

Objective To evaluate the immunogenicity of primary poliovirus vaccination schedules in 2014 and 2016-before and after introduction of bivalent oral poliovirus vaccine（ b OPV） in Beijing.Methods In 2014,the primary polio vaccination schedule consisted of 3 doses of trivalent oral poliovirus vaccine（ tOPV）; in 2016,the schedule was 1 dose of inactivated poliovirus vaccine（ IPV） followed by 2 doses of b OPV. Subjects were infants from 2 districts in Beijing who had finished their primary polio immunization schedule 4-8 weeks prior to study enrollment. We collected blood samples from subjects to detect neutralizing antibody against polio. We also collected locally-stored OPV samples to measure vaccine titers. Results Our study included 72 children in 2014 and 68 children in 2016. In 2014,the polio antibody positivity rates after primary immunization were 98. 61% for type Ⅰ poliovirus and 100% for type Ⅲ poliovirus; the median（ quartile range） titers（ 1 ∶） were 1 536（ 1 024-1 536） for typeⅠ and1 536（ 512-1 536） for type Ⅲ. In 2016,the polio antibody positivity rates for type Ⅰ and Ⅲ poliovirus were both 100% after primary immunization; the median（ quartile range） titers of antibody were 1 024（ 512-1 536） for type Ⅰ and 1 536（ 1 024-1 536） for type Ⅲ. The differences in antibody titers between type Ⅰ and type Ⅲ poliovirus were statistically significant between 2014 and 2016（ type Ⅰ： χ^2= 8. 77,P = 0. 038; type Ⅲ： χ^2=16. 76,P = 0. 001）. The average vaccine titer was 6. 1 ± 0. 1 Lg CCID50 per dose for tOPV in 2014,and6. 9 ± 0. 2 Lg CCID50 per dose for b OPV in 2016（ t =-7. 76,P〈 0. 001）. Conclusions Immunogenicity against type Ⅰ and Ⅲ poliovirus of a sequential IPV-b OPV schedule was good after introduction of b OPV,and was similar to that of a 3-dose tOPV schedule or an IPV-tOPV sequential schedule. Locallystored vaccines were qualified,showing a good cold chain conditions.