Abstract：
BACKGROUND: There has been no data on the immunogenicity and safety of the 4th booster dose of the sIPV immunization in 18-24 months old children in post-marketing studies of large cohort providing with robust results.
METHODS: In a phase Ⅳ randomized, double-blinded clinical trial, 1200 participants aged 2 months were immunized with three consecutive doses of sIPV at 2, 3, and 4 months old to complete primary immunization. Out of the 1200 participants, 1129 received the 4th dose of sIPV as booster immunization. Immunogenicity was evaluated in 1100 participants.
RESULTS: Seropositive rates of the anti-poliovirus type 1, 2, and 3 neutralizing antibodies were 99.9 %, 98.0 %, 98.2 %, respectively, with GMTs of 557.0, 146.1, 362.0 one year after primary vaccination. After booster vaccination between 18 and 24 months old, the seropositive rates for 3 types all reached 100.0 %, with GMTs of 8343.6, 5039.6, 5492.0, respectively. Particularly for the anti-poliovirus type 2 antibody, the GMT was 230.4 after primary immunization, maintained to 146.1 one year after primary immunization, and increased to as high as 5039.6 after booster vaccination. The GMT ratios between each batch groups after booster immunization were between 0.67 and 1.50, meeting the immunological equivalence criteria. The incidence rate of adverse reaction was 23.0 %, which was comparable to those in the phase Ⅲ trial but had a lower incidence. Furthermore, no SUSAR was reported in this study.
CONCLUSIONS: In conclusion, as the anti-poliovirus antibodies gradually waned one year post sIPV primary vaccination, especially the type 2 antibody waned to a very low level, suggesting the importance of the booster immunization for children at the age of 18-24 months old. The booster shot can greatly enhance the antibody level and protect children from the potential risk of infection with WPV and VDPV by supplementing the anti-poliovirus type 2 immunity gap in the current real world. Clinic Trial Registration. NCT04224519.
METHODS: In a phase Ⅳ randomized, double-blinded clinical trial, 1200 participants aged 2 months were immunized with three consecutive doses of sIPV at 2, 3, and 4 months old to complete primary immunization. Out of the 1200 participants, 1129 received the 4th dose of sIPV as booster immunization. Immunogenicity was evaluated in 1100 participants.
RESULTS: Seropositive rates of the anti-poliovirus type 1, 2, and 3 neutralizing antibodies were 99.9 %, 98.0 %, 98.2 %, respectively, with GMTs of 557.0, 146.1, 362.0 one year after primary vaccination. After booster vaccination between 18 and 24 months old, the seropositive rates for 3 types all reached 100.0 %, with GMTs of 8343.6, 5039.6, 5492.0, respectively. Particularly for the anti-poliovirus type 2 antibody, the GMT was 230.4 after primary immunization, maintained to 146.1 one year after primary immunization, and increased to as high as 5039.6 after booster vaccination. The GMT ratios between each batch groups after booster immunization were between 0.67 and 1.50, meeting the immunological equivalence criteria. The incidence rate of adverse reaction was 23.0 %, which was comparable to those in the phase Ⅲ trial but had a lower incidence. Furthermore, no SUSAR was reported in this study.
CONCLUSIONS: In conclusion, as the anti-poliovirus antibodies gradually waned one year post sIPV primary vaccination, especially the type 2 antibody waned to a very low level, suggesting the importance of the booster immunization for children at the age of 18-24 months old. The booster shot can greatly enhance the antibody level and protect children from the potential risk of infection with WPV and VDPV by supplementing the anti-poliovirus type 2 immunity gap in the current real world. Clinic Trial Registration. NCT04224519.
摘要：
背景：在大型队列的上市后研究中，没有关于第4次加强剂量的sIPV免疫在18-24个月大的儿童中的免疫原性和安全性的数据，这些研究提供了可靠的结果。
方法：在Ⅳ期随机分组中，双盲临床试验，1200名2个月大的参与者在2、3和4个月大的时候用三个连续剂量的sIPV免疫以完成初次免疫。在1200名参与者中，1129接受第4剂sIPV作为加强免疫。在1100名参与者中评估了免疫原性。
结果：抗脊髓灰质炎病毒1型、2型和3型中和抗体的血清阳性率为99.9%，98.0%,98.2%,分别,初次疫苗接种后一年的GMTs为557.0、146.1、362.0。在18至24个月大的加强疫苗接种后，3种类型的血清阳性率均达到100.0%，GMT分别为8343.6、5039.6、5492.0。特别是抗脊髓灰质炎病毒2型抗体，初次免疫后的GMT为230.4，在初次免疫接种后一年维持到146.1，并在加强疫苗接种后增加到高达5039.6。加强免疫后各批次组之间的GMT比率在0.67和1.50之间,满足免疫学等效性标准。不良反应发生率为23.0%,与Ⅲ期试验相当，但发生率较低。此外，本研究未报道SUSAR。
结论：结论：随着抗脊髓灰质炎病毒抗体在sIPV初次疫苗接种后一年逐渐减弱，特别是2型抗体下降到非常低的水平，提示加强免疫对18-24个月大的儿童的重要性。加强注射可以大大提高抗体水平，并通过补充当前现实世界中的抗脊髓灰质炎病毒2型免疫缺口来保护儿童免受WPV和VDPV感染的潜在风险。诊所试验登记。NCT04224519。
方法：在Ⅳ期随机分组中，双盲临床试验，1200名2个月大的参与者在2、3和4个月大的时候用三个连续剂量的sIPV免疫以完成初次免疫。在1200名参与者中，1129接受第4剂sIPV作为加强免疫。在1100名参与者中评估了免疫原性。
结果：抗脊髓灰质炎病毒1型、2型和3型中和抗体的血清阳性率为99.9%，98.0%,98.2%,分别,初次疫苗接种后一年的GMTs为557.0、146.1、362.0。在18至24个月大的加强疫苗接种后，3种类型的血清阳性率均达到100.0%，GMT分别为8343.6、5039.6、5492.0。特别是抗脊髓灰质炎病毒2型抗体，初次免疫后的GMT为230.4，在初次免疫接种后一年维持到146.1，并在加强疫苗接种后增加到高达5039.6。加强免疫后各批次组之间的GMT比率在0.67和1.50之间,满足免疫学等效性标准。不良反应发生率为23.0%,与Ⅲ期试验相当，但发生率较低。此外，本研究未报道SUSAR。
结论：结论：随着抗脊髓灰质炎病毒抗体在sIPV初次疫苗接种后一年逐渐减弱，特别是2型抗体下降到非常低的水平，提示加强免疫对18-24个月大的儿童的重要性。加强注射可以大大提高抗体水平，并通过补充当前现实世界中的抗脊髓灰质炎病毒2型免疫缺口来保护儿童免受WPV和VDPV感染的潜在风险。诊所试验登记。NCT04224519。
