暂无摘要。

BACKGROUND: To assess the immunogenicity of the current primary polio vaccination schedule in China and compare it with alternative schedules using Sabin or Salk-strain IPV (sIPV, wIPV).
METHODS: A cross-sectional investigation was conducted at four sites in Chongqing, China, healthy infants aged 60-89 days were conveniently recruited and divided into four groups according to their received primary polio vaccination schedules (2sIPV + bOPV, 2wIPV + bOPV, 3sIPV, and 3wIPV). The sero-protection and neutralizing antibody titers against poliovirus serotypes (type 1, 2, and 3) were compared after the last dose.
RESULTS: There were 408 infants completed the protocol. The observed seropositivity was more than 96% against poliovirus types 1, 2, and 3 in all groups. IPV-only groups induced higher antibody titers(GMT) against poliovirus type 2 (Median:192, QR: 96-384, P<0.05) than the \"2IPV + bOPV\" group. While the \"2IPV + bOPV\" group induced significantly higher antibody titers against poliovirus type 1 (Median:2048, QR: 768-2048, P<0.05)and type 3 (Median:2048, QR: 512-2048, P<0.05) than the IPV-only group.
CONCLUSIONS: Our findings have proved that the two doses of IPV with one dose of bOPV is currently the best polio routine immunization schedule in China.

This open-label, randomized, phase 3 study in China (V260-074; NCT04481191) evaluated the immunogenicity and safety of concomitant and staggered administration of three doses of an oral, live, pentavalent rotavirus vaccine (RV5) and three doses of an intramuscular, inactivated poliomyelitis vaccine (IPV) in 400 healthy infants. The primary objective was the non-inferiority of neutralizing antibody (nAb) responses in the concomitant- versus the staggered-use groups. Antibody responses were measured at baseline and 1-month post-dose 3 (PD3). Parents/legal guardians recorded adverse events for 30 or 15 d after study vaccinations in the concomitant-use or staggered-use groups, respectively. At PD3, >98% of participants seroconverted to all three poliovirus types, and the primary objective was met as lower bounds of the two-sided 95% CI for between-group difference in nAb seroconversion percentages ranged from - 4.3% to - 1.6%, for all poliovirus types, p < .001. At PD3, geometric mean titers (GMTs) of nAb responses to poliovirus types 1, 2, and 3 in the concomitant-use group and the staggered-use group were comparable; 100% of participants had nAb titers ≥1:8 and ≥1:64 for all poliovirus types. Anti-rotavirus serotype-specific IgA GMTs and participants with ≥3-fold rise in postvaccination titers from baseline were comparable between groups. Administration of RV5 and IPV was well tolerated with comparable safety profiles in both groups. The immunogenicity of IPV in the concomitant-use group was non-inferior to the staggered-use group and RV5 was immunogenic in both groups. No safety concerns were identified. These data support the concomitant use of RV5 and IPV in healthy Chinese infants.

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.

BACKGROUND: This study aimed to evaluate the immunogenicity and safety of different types of poliovirus vaccines.
METHODS: A randomized, blinded, single-center, parallel-controlled design was employed, and 360 infants aged ≥ 2 months were selected as study subjects. They were randomly assigned to bOPV group (oral Sabin vaccine) and sIPV group (Sabin strain inactivated polio vaccine), with 180 infants in each group. Adverse reaction events in the vaccinated subjects were recorded. The micro-neutralization test using cell culture was conducted to determine the geometric mean titer (GMT) of neutralizing antibodies against poliovirus types I, II, and III in different groups, and the seroconversion rates were calculated.
RESULTS: Both groups exhibited a 100% seropositivity rate after booster immunization. The titers of neutralizing antibodies for the three types were predominantly distributed within the range of 1:128 to 1:512. The fold increase of type I antibodies differed markedly between the two groups (P < 0.05). Moreover, the fold increase of type II and type III antibodies for poliovirus differed slightly between the two groups (P > 0.05). The fourfold increase rate in sIPV group was drastically superior to that in bOPV group (P < 0.05). When comparing the post-immunization GMT levels of type I antibodies in individuals who completed the full course of spinal muscular atrophy vaccination, bOPV group showed greatly inferior levels to sIPV group (P < 0.05). For type II and type III antibodies, individuals in bOPV group demonstrated drastically superior post-immunization GMT levels to those in sIPV group (P < 0.05). The incidence of adverse reactions between the bOPV and sIPV groups differed slightly (P > 0.05).
CONCLUSIONS: These findings indicated that both the oral vaccine and inactivated vaccine had good safety and immunogenicity in infants aged ≥ 2 months. The sIPV group generated higher levels of neutralizing antibodies in serum, particularly evident in the post-immunization GMT levels for types II and III.

现对新疆防治肉毒中毒、霍乱、戊型肝炎和脊髓灰质炎流行进行了历史回顾。.

In 2019, we conducted a cross-sectional study for polio virus seroprevalence in Guangdong province, China. We assessed the positivity rates of poliomyelitis NA and GMT in serum across various demographic groups, and the current findings were compared with pre-switch data from 2014. Using multistage random sampling method, four counties/districts were randomly selected per city, and within each, one general hospital and two township hospitals were chosen. Healthy individuals coming for medical checkups or vaccination were invited. A total of 1318 individual samples were collected and tested. In non-newborn population, age-dependent positivity rates ranged from 77.8% to 100% for PV1 NA and 70.3% to 98.9% for PV3 NA (p < .01). The lowest GMT values for both types (17.03 and 8.46) occurred in the 20 to <30 years age group, while peak GMTs for PV1 and PV3 were observed in 1 to <2 (340.14) and 0 to <1-year (168.90) age groups, respectively. GMTs for PV1 (P = .002) and PV3 (P = .007) in Eastern Guangdong were lower than those in the other three regions. Male participants showed higher GMTs than females (P = .016 and .033, respectively). In newborn population, both males and females showed higher PV1 NA positivity rates and GMTs compared to PV3 (p < .05). Post-switch PV3 NA positivity rates were higher than pre-switch rates (p = .016). GMTs of both PV1 and PV3 were significantly higher post-switch (p < .001). The positivity rates of NAs and GMTs remain high level, which play an important role in resisting poliomyelitis infection. Effect of the converted immunization program was more pronounced than that before.

The eradication of poliomyelitis is a landmark achievement in the history of public health, providing strong protection for children\'s health. The introduction of the Chinese Regulations for the Manufacture and Control of Live Poliovirus Vaccine is a prerequisite and safeguard for the large-scale production and use of domestically produced live poliovirus vaccines, serving as an indispensable component of vaccine safety. This article, based on archival documents, letters, collections of essays, and oral interviews, examines the historical experience of the development of Chinese Regulations for the Manufacture and Control of Live Poliovirus Vaccine. It contends that the emphasis on localization and the active engagement in international cooperation are critical factors in the swift introduction of Chinese Regulations for the Manufacture and Control of Live Poliovirus Vaccine.

In 2013, a case of immunodeficiency vaccine-derived poliovirus (iVDPV) was identified in Jiangxi Province, China. In this study, we purified 14 type 3 original viral isolates from this case and characterized the molecular evolution of these iVDPVs for 298 days. Genetic variants were found in most of the original viral isolates, with complex genetic and evolutionary relationships among the variants. A phylogenetic tree constructed based on the P1 region showed that these iVDPVs were classified into lineage A and B. The dominant lineage B represents a major trend in virus evolution. The nucleotide substitution rate at the third codon position (3CP) estimated by the BEAST program was 1.76 × 10-2 substitutions/site/year (95% HPD: 1.23-2.39 × 10-2). The initial OPV dose was given dating back to March 2013, which was close to the time of the last OPV vaccination, suggesting that OPV infection may have originated with the last dose of vaccine. Recombinant analysis showed that these iVDPVs were inter-vaccine recombinants with two recombination patterns, S3/S2/S1 and S3/S2/S3/S2/S1. Whole genome sequence analysis revealed that key nucleotide sites (C472U, C2034U, U2493C) associated with the attenuated phenotype of Sabin 3 have been replaced. Temperature sensitivity test showed that all tested strains were temperature-sensitive, except for the variant Day11-5. Interestingly, we observed that the variant Day11-5 temperature resistance properties may be associated with the Lys to Met substitution at the VP2-162 site. Serological test and whole genome sequence analysis showed that the seropositivity rate remained high, and mutations in the antigenic sites did not significantly alter neutralization ability.

Sabin strain inactivated poliovirus vaccine (hereinafter as \"sIPV\") has been marketed globally in recent years, and more data on its immune persistence are needed.
This is a phase IV, open-labeled, parallel-controlled observational study based on phase III clinical trial as required by the China National Medical Products Administration (NMPA). At least 450 subjects aged four years (48-54 months) who received four doses at 2, 3, 4 and 18 months of age of sIPV or wild strain poliovirus vaccine (wIPV) in phase III clinical trial enrolled at a 2:1 ratio and collected blood samples for neutralizing antibody testing.
A total of 500 subjects of four years old (334 in the sIPV group and 166 in wIPV group) were finally enrolled. The seropositivity rates (≥1:8) of neutralizing antibodies against serotype I-III were all 100.00% in all participants, and the geometric mean titers (GMT) were 1117.33 vs. 337.77 against serotype I, 632.72 vs. 267.34 against serotype Ⅱ, 1665.98 vs. 923.02 against serotype III in the sIPV group and wIPV group respectively at 4 years old. The seropositivity rates and GMTs of neutralizing antibodies in the test group were non-inferior to that of the control group against all three serotypes at different time points (P < 0.0001). The antibody GMT experienced a 10-fold, 8-fold, and 7-fold decline for serotypes I, Ⅱ, and III in the sIPV group, and a 13-fold, 7-fold, and 7-fold decline in the wIPV group from one month after booster vaccination to 4 years old.
The neutralizing antibody level is much higher than the seroprotection cutoff (≥1:8) among children of 4 years old who completed the four-dose vaccination of either sIPV or wIPV. Therefore, another booster vaccination is not recommended at 4 years old. Longer immune persistence observation is still ongoing.
ClinicalTrials.gov Identifier: NCT04989231.