Objective: To evaluate the safety of population based sequential vaccination schedule of inactivated poliovirus vaccines prepared with different strains. Methods: This randomized, parallel-group controlled trial was conducted from March, 2017 to May, 2018, in Shanghai. Adverse reaction data of Sabin strain inactivated polio vaccine (sIPV), wild strains inactivated polio vaccines (wIPV) and bivalent types Ⅰ and Ⅲ oral poliomyelitis vaccine (bOPV) were systematically collected through active observation in 1 917 infants in Shanghai after the vaccination at 2, 3, 4 months old. The eligible infants aged 2 months were divided into 4 groups: ①sIPV+sIPV+bOPV group; ②sIPV+wIPV+bOPV group; ③wIPV+sIPV+bOPV group; ④wIPV+wIPV+bOPV group. Results: The incidence of adverse reaction 30 days later after 3 basic dose vaccinations was 16.79% (946/5 633). No serious adverse reaction was reported. Local and systemic reactions were mainly mild. Common local reactions were pain, erythema, cutaneous nodule, etc.; and common systemic reactions were abnormal crying, drowsiness, diarrhea and appetite lost, etc.. The incidence of local reactions 30 days later after 3 basic dose vaccinations was 1.65% (93/5 633), and the incidence rates of grade 1-3 reactions were1.26% (71/5 633), 0.21% (12/5 633) and 0.20% (11/5 633) respectively. The incidence rate of systemic reactions 30 days later after 3 basic vaccinations was 15.14% (853/5 633), and the incidence rates of grade 1-3 reactions were 11.33% (638/5 633), 3.18% (179/5 633) and 0.64% (36/5 633) respectively. There were no significant differences in the rate of grade 3 reaction among different groups (χ(2)=4.17, P=0.24). Conclusions: No severe adverse reactions related to sequential vaccination of different strain inactivated polio vaccines were observed, most of reactions were mild and all of them were cured. It is safe to use sIPV and wIPV simultaneously or alternately for childhood sequential vaccination.
目的： 评价使用不同毒株脊髓灰质炎灭活疫苗（IPV）开展序贯免疫程序在大规模人群中使用的安全性。 方法： 于2017年3月至2018年5月，采用随机、平行对照设计，以Sabin株脊髓灰质炎灭活疫苗（sIPV）、野毒株脊髓灰质炎灭活疫苗（wIPV）和Ⅰ+Ⅲ型脊髓灰质炎减毒活疫苗（bOPV）作为研究疫苗，在上海市选择1 917例2月龄婴儿为研究对象，分为4组：①sIPV+sIPV+bOPV；②sIPV+wIPV+bOPV；③wIPV+sIPV+bOPV；④wIPV+wIPV+bOPV，采用主动观察的方法观察其在2、3、4月龄接种后的不良反应。 结果： 4组完成3剂基础免疫接种后总的不良事件发生率为16.79%（946/5 633），各组均未报告严重不良事件，全身和局部反应均以轻度反应为主。常见局部反应为注射部位疼痛、红和硬结等；全身反应为异常哭闹、嗜睡、腹泻和食欲下降等。接种后30 d内，局部反应率为1.65%（93/5 633），其中轻度、中度和重度反应率分别为1.26% （71/5 633）、0.21%（12/5 633）和0.20%（11/5 633）；全身反应率为15.14%（853/5 633），其中轻度、中度和重度反应率分别为11.33%（638/5 633）、3.18%（179/5 633）和0.64%（36/5 633）。各组间重度反应率差异无统计学意义（χ(2)=4.17，P=0.24）。 结论： 本研究中未观察到使用不同毒株脊髓灰质炎灭活疫苗开展序贯免疫程序接种相关的严重不良事件，多数为轻度的不良反应，所有反应均痊愈。同时或交替使用sIPV和wIPV开展序贯免疫程序对于适龄儿童均具有良好的预防接种安全性。.

The emergence of vaccine-associated paralytic poliomyelitis has become an ongoing burden of poliomyelitis. During this special period from OPV to IPV-only immunization schedule, we did a meta-analysis to compare the immunogenicity of sequential IPV and OPV versus IPV alone in healthy infants.
This systematic review and meta-analysis was registered at international prospective register of systematic reviews (PROSPERO), and the number was CRD42017054889. We performed it as described.
Finally, 6 articles were qualified for our review. The results showed that seroconversion rates against all 3 serotype polioviruses were non-inferior and Geometric mean antibody titers (GMTs) were superior in sequential schedules compared with IPV-only schedule. Thus, the sequential vaccination schedules could induce a stronger immunogenicity.
To decrease vaccine-associated and vaccine-derived poliomyelitis, it is a reasonable option to select sequential schedules during this special transition from OPV to IPV-only immunization schedule, which coincides with the current WHO recommendations.

Use of inactivated poliovirus vaccine (IPV) in Jinan during the polio eradication endgame has not been previously documented. Two IPV-containing vaccines were made available as an option for Jinan parents in 2009. We describe coverage levels and patterns of use of IPV over time using data from the Jinan Childhood Immunization Information Management System (JNCIIMS).
Children born between January 2010 and December 2014 who were registered in JNCIIMS were included in this study. Vaccination records were obtained from JNCIIMS on April 30, 2015. JNCIIMS distinguishes among available poliovirus vaccines; doses administered data were used to describe IPV usage over time. We identified the polio vaccination sequences used by children in the 2012 and 2013 birth cohorts. Coverage estimates were analyzed by birth cohort and migration status. We developed 3 categories for analysis: \"resident child,\" \"migrant child\" and \"other child\" according to migration status.
In total, 12,354 (11.7%) IPV, 5,893(5.6%) DTP-IPV-Hib vaccine and 87,054(82.7%) OPV doses were administered to children in the 2010 to 2014 birth cohorts. The proportion of children using an IPV-only schedule increased each year, consistent with the introduction of IPV that is called for by the Polio Eradication Endgame Strategic Plan 2013-2018. During this time, 4.7% children used a schedule containing both IPV and oral poliovirus vaccine (OPV). In the 2012 to 2013 birth cohorts, 14.4% children used an IPV-only schedule; 5.7% children used a sequential schedule, and 79.9% used OPV-only schedule. Use of IPV only schedules was higher among migrant children than among resident children. Among those sequential schedule using both IPV and OPV, 87.2% children used IPV for the first dose and 12.8% used OPV for the first dose.
JNCIIMS provided a mechanism for tracking IPV and OPV vaccination patterns, and showed areas in need of improvement. Ensuring appropriately sequenced IPV and OPV supports reduction of risk of vaccine associated paralytic polio.

BACKGROUND: OPV is the only poliovirus vaccine used in the China EPI system, although IPV is available in the private market. We compared immunigencity and persistence among different schedules of IPV and OPV.
METHODS: 536 Chinese infants were enrolled into 4 groups receiving different schedules administered at 2, 3, and 4 months of age: IPV-OPV-OPV, IPV-IPV-OPV, IPV-IPV-IPV, and OPV-OPV-OPV. The I-I-I group received an 18-month IPV booster dose. Blood samples were collected before the first dose, after the third dose, and at 18 months for all groups, and also after the booster dose for the I-I-I group. Polio neutralizing antibody titers were assessed, and seroprotection rates were calculated after primary immunization and at 18 months of age.
RESULTS: Before the first dose, GMTs of the 4 groups ranged from 2.96 to 6.89, and seroprotection rates ranged from 17.6% to 54.3%. After 3 doses, the GMT of the I-O-O and I-I-O groups ranged from 901.09 to 1,110.12, and the GMT of the I-I-I group range was 212.02 to 537.52, significantly lower than for the 2 sequential schedules (P<0.001). Seroprotection rates were 98.1% to 100%, with no significant differences among groups. At 18 months of age, the GMTs declined to a range of 527.00 to 683.44 in the I-O-O and I-I-O groups, and declined to 150.04 to 239.89 in the I-I-I group, significantly lower than for the other 3 groups (P<0.001).
CONCLUSIONS: The sequential schedules achieved high GMTs and seroprotection. The IPV-only schedule achieved high seroprotection but with lower GMTs. Sequential schedules are suitable for China. With the 2 sequential schedules, GMTs remained high at 18 months of age and were not inferior to the OPV-only schedule. Thus, with a sequential schedule, the booster dose could be given at 4 years of age, the same age as the current OPV booster dose.