In 2024 herpangina surveillance in Yuhuan City, China, two Coxsackievirus B4 strains (Z168, Z296) were identified. Full-length genome sequencing revealed that both strains belonged to genotype D that was first documented in eastern China. The two strains showed the highest nucleotide similarity to Coxsackievirus B4 strains isolated in the UK (2017). In the recombination events, both major parental strains were identified as Coxsackievirus B4 strains isolated in France (2015 and 2017). Echovirus 11 and Coxsackievirus B5 were detected as minor parental strains, indicating intertypic recombination. Phylogenetically, Z168 and Z296 clustered closely with European genotype D strains (2013-2024) but were distant from previously reported Chinese genotype D strains (Yunnan 2013-2016; Tianjin 2019). Bayesian phylogeographic reconstruction suggested a complex global transmission history of Coxsackievirus B4 with increasing cross-border transmission in recent decades, including genotypes A, D and E transmitting among North America, Europe and Asia. Both strains possessed a unique amino acid substitution within a putative neutralizing epitope, suggesting potential antigenic evolution. These findings indicate that the Z168 and Z296 strains likely represent a recent European introduction, forming a lineage distinct from earlier Chinese genotype D isolates. This highlights the need for molecular surveillance to track Coxsackievirus B4 emergence and evolution.

The Zagreb and Essen regimens are comparable in terms of immunogenicity; however, how these regimens impact the immunogenicity of booster vaccination remains unknown. We conducted a clinical trial to assess the immunogenicity of booster vaccination with a purified Vero cell rabies vaccine after primary vaccination with the Zagreb or Essen regimens. This randomized, open-label, controlled, phase 3 trial, conducted in Shangyu City and Shengzhou City, Zhejiang Province, China, was divided into the primary and booster vaccination phases. After screening, all eligible participants were allocated to groups A, B, C, D, E, or F. Groups A, B, and C received the Zagreb regimen as the primary vaccine, while groups D, E, and F received the Essen regimen. The booster vaccination was conducted 6 months after the primary vaccination. Groups B and E received one dose of the booster, while groups C and F received two doses. Blood samples were collected before the booster, at 14 days after the booster, and at approximately 6 months after the booster. Safety was assessed from the first booster dose to 6 months after the final dose. A total of 718 participants completed the booster vaccination. The antibody positive rate (APR) of groups B, C, E, and F after the booster was 100%. The antibody titer rose significantly even after one booster, and was much higher in groups B (48.80 IU/ml) and C (64.38 IU/ml) (receiving Zagreb) than in groups E (34.25 IU/ml) and F (42.89 IU/ml) (receiving Essen). Although the incidence of ARs was higher in groups B (11.22%) and C (15.79%) than in groups E (3.68%) and F (10.87%), they were all mild and short-lived. No serious adverse events (SAEs) associated with vaccination were reported. The immunogenicity of booster vaccination after the Zagreb regimen was significantly higher than that after the Essen regimen. One booster may be sufficient to raise the antibody titer above the 0.5 IU/mL target. Clinical trial registration: This trial is registered at http://www.chinadrugtrials.org.cn/index.html under the registration number CTR20210426 at 08/03/2021.

Several human papillomavirus (HPV) L1-based virus-like particle (VLP) vaccines are in development to meet future global vaccination needs. Type-specific monoclonal antibodies with good reactivity to all types of vaccines are urgently needed to evaluate vaccine potency. In this study, binding activity, neutralizing activity, conformational sensitivity, immunodominance in human serum, and versatility were compared among antibodies. A broad-spectrum binding antibody (C4-F5-127) was selected as the capture antibody; four type-specific neutralizing antibodies (6-F5-77, 11-F5-187, 16-F5-196, and 18-F5-203) were selected as detection antibodies for HPV6, 11, 16, and 18, respectively. These antibodies formed a standardized and universal in vitro relative potency (IVRP) assay kit. High-resolution cryo-electron microscopy (cryo-EM) structures of HPV6-6-F5-77, HPV11-11-F5-187, HPV16-16-F5-196 and HPV18-18-F5-203 complexes define the location and nature of epitopes, revealing serotype specific binding modes and neutralization mechanisms. The IVRP results were correlated with potency data from mouse models, offering an efficient alternative to in vivo potency experiments.

Herpangina is an acute pediatric illness caused by enteroviruses, yet the predominant circulating serotype in mainland China has not been well characterized. In this study, Coxsackievirus A2 (CV-A2) emerged as the dominant serotype among herpangina cases in Yuhuan City, Zhejiang Province. These findings underscore the importance of further research into the epidemiological distribution and molecular features of CV-A2 in this region. A total of 133 child herpangina cases were included during May and June 2024. Enteroviruses were detected using RT-PCR, followed by serotyping and sequencing. Phylogenetic and recombination analyses were performed to assess genetic diversity and evolutionary relationships. Among the 133 cases (median age: 3 years), 88.7

Decades of human papillomavirus (HPV) L1-based virus-like particle (VLP) vaccines, produced using diverse expression systems and production processes, are in development to meet future global vaccination needs. Type-specific monoclonal antibodies with good reactivity to all types of vaccines are urgently needed to evaluate vaccine efficacy. In this study, binding activity, neutralizing activity, conformational sensitivity, immunodominance in human serum, and versatility were compared among antibodies. A broad-spectrum binding antibody (F5-127) was selected as the capture antibody; four type-specific neutralizing antibodies (F5-77, F5-187, F5-196, and F5-203) were selected as detection antibodies for HPV6, 11, 16, and 18, respectively. These antibodies formed a standardized and universal in vitro relative potency (IVRP) assay kit useful for all quadrivalent HPV vaccines. High-resolution cryo-electron microscopy (cryo-EM) structures of HPV6-F5-77, HPV11-F5-187, HPV16-F5-196 and HPV18-F5-203 complexes define the location and nature of epitopes, revealing serotype specific binding modes and neutralization mechanisms. These four antibodies target regions which exhibit structural plasticity within the L1 pentamer, rather than quaternary sites constructed by particle formation, conferring conformational sensitivity and reactive universality, pre-requisites as IVRP candidate antibodies. The IVRP results were correlated with efficacy data from mouse models, demonstrating the kit’s sensitivity in detecting the degree of heat-accelerated destruction. Therefore, the IVRP method established in this study offers an efficient alternative to in vivo efficacy experiments for future vaccines.

Background Rabies continues to be a significant global public health concern, particularly in the Asia region where it is associated with high mortality rate. The administration of effective vaccination is essential in preventing this potentially fatal viral infection. The objective of this study was to evaluate the immunogenicity and safety of two rabies vaccination schedules: the Zagreb (2-1-1) and Essen (1-1-1-1-1) regimens, in a cohort of healthy Chinese individuals aged 10-60 years.Methods We conducted a randomized, open-label, controlled, non-inferiority phase 3 trial from July 2021 to November 2022, enrolling a total of 1200 participants. Participants were randomly assigned to receive either the Zagreb or Essen vaccination regimen. The primary outcomes were safety, immunogenicity, and immune persistence. Safety was monitored through adverse event reporting, while immunogenicity was determined by measuring rabies-virus-neutralizing antibody (RVNA) concentrations using the rapid fluorescent focus inhibition test (RFFIT). Immune persistence was evaluated at 3, 6, and 12 months post-vaccination.Results The two vaccination regimens exhibited comparable safety records, with mild and transient adverse events predominantly occurring within 0-3 days post-vaccination. The Zagreb regimen demonstrated non-inferiority in terms of seroconversion rates and geometric mean concentrations (GMCs) of antibodies compared to the Essen regimen at both 14 days post-first vaccination and 14 days post-full vaccination. Additionally, both groups displayed nearly 100% seropositivity rate at 3,6, and 12 months. No serious adverse events associated with vaccination were reported.Conclusion The findings of this Phase 3 clinical trial provide compelling evidence that the Zagreb regimen is a feasible alternative when compared to the Essen regimen for rabies vaccination, offering a more pragmatic and cost-efficient approach to rabies prevention and control.Clinical trial registration http://www.chinadrugtrials.org.cn, identifier CTR20210426.

ABSTRACT Background Because SARS-CoV-2 mutations and immunity wane over time, a third dose of heterologous COVID-19 vaccine is proposed for individuals primed with inactivated COVID-19 vaccine. Research design and methods We conducted a single-center, open-label trial to assess the safety, immunogenicity, and immune-persistence of a heterologous BBIBP-CorV/ZF2001 prime-boost vaccination in Chinese adults. 480 participants who had been primed with two doses of BBIBP-CorV, received a third dose of ZF2001 after an interval of 3–4, 5–6, or 7–9 months. Results The overall incidence of adverse reactions within 30 days after vaccination was 5.83%. No serious adverse reactions were reported. The respective geometric mean titers (GMTs) of neutralizing antibodies for 3–4, 5–6, and 7–9 months groups at baseline were 2.06, 2.02, and 2.10; which increased to 55.42, 63.45, and 62.06 on day 14; then decreased to 17.53, 23.79, and 26.73 on day 30; before finally waning to 8.29, 9.24, and 9.51 on day 180. After the booster, the three groups showed no significant differences in GMTs. GMTs were lower in older participants than younger participants. Conclusions A heterologous BBIBP-CorV/ZF2001 prime-boost vaccination was safe and immunogenic. Prime-boost intervals did not affect the immune response. The immune response was weaker in older adults than younger adults. Clinical trial identifier NCT05205083

Background In response to SARS-CoV-2 mutations and waning antibody levels after two-dose inactivated vaccines, we assessed whether a third dose of recombinant protein subunit vaccine (ZF2001) boosts immune responses. Methods An open-label single-center non-random trial was conducted on people aged 18 years and above at five sites in China. All participants received a two-dose inactivated vaccine (CoronaVac) as their prime doses within 3–9 months of the trial. Primary outcomes were safety and immunogenicity, primarily the geometric mean titers (GMTs) of neutralizing antibodies to live wildtype SARS-CoV-2. Results A total of 480 participants (median age, 51; range 21–84 years) previously vaccinated with two-dose CoronaVac received a third booster dose of ZF2001 3–4, 5–6, or 7–9-months later. The overall incidence of adverse reactions within 30 days after vaccination was 5.83% (28/480). No serious adverse reactions were reported after the third dose of ZF2001. GMTs in the 3–4-, 5–6-, and 7–9-month groups before vaccination were 3.96, 4.60, and 3.78, respectively. On Day 14, GMTs increased to 33.06, 47.51, and 44.12, respectively. After the booster, GMTs showed no significant difference among the three prime-boost interval groups (all P>0.05). Additionally, GMTs in older adults were lower than those in younger adults on Day 14 for the three groups (P=0.0005, P<0.0001, and P<0.0001). Conclusion Heterologous boosting with ZF2001 was safe and immunogenic, and prime-boost intervals did not affect the immune response. The immune response was weaker in older than younger adults.

A randomized, double-blind, placebo-controlled multicenter trial was conducted in healthy Chinese infants to assess the efficacy and safety of a hexavalent live human-bovine reassortant rotavirus vaccine (HRV) against rotavirus gastroenteritis (RVGE). A total of 6400 participants aged 6-12 weeks were enrolled and randomly assigned to either HRV (n = 3200) or placebo (n = 3200) group. All the subjects received three oral doses of vaccine four weeks apart. The vaccine efficacy (VE) against RVGE caused by rotavirus serotypes contained in HRV was evaluated from 14 days after three doses of administration up until the end of the second rotavirus season. VE against severe RVGE, VE against RVGE hospitalization caused by serotypes contained in HRV, and VE against RVGE, severe RVGE, and RVGE hospitalization caused by natural infection of any serotype of rotavirus were also investigated. All adverse events (AEs) were collected for 30 days after each dose. Serious AEs (SAES) and intussusception cases were collected during the entire study. Our data showed that VE against RVGE caused by serotypes contained in HRV was 69.21% (95%CI: 53.31-79.69). VE against severe RVGE and RVGE hospitalization caused by serotypes contained in HRV were 91.36% (95%CI: 78.45-96.53) and 89.21% (95%CI: 64.51-96.72) respectively. VE against RVGE, severe RVGE, and RVGE hospitalization caused by natural infection of any serotype of rotavirus were 62.88% (95%CI: 49.11-72.92), 85.51% (95%CI: 72.74-92.30) and 83.68% (95%CI: 61.34-93.11). Incidences of AEs from the first dose to one month post the third dose in HRV and placebo groups were comparable. There was no significant difference in incidences of SAEs in HRV and placebo groups. This study shows that this hexavalent reassortant rotavirus vaccine is an effective, well-tolerated, and safe vaccine for Chinese infants.

Background: No data on the safety and efficacy of a live attenuated influenza vaccine in China have ever been reported. Methods: At a site of a phase 3 randomized, double-blind, placebo-controlled clinical trial in eastern China, eligible healthy children aged 3-17 years underwent randomization to receive live attenuated vaccine or placebo at a ratio of 1:1. The primary objective of the study was the prevention of laboratory-confirmed influenza illness during the surveillance period, starting on day 15 after vaccination. Results: A total of 2000 participants were enrolled, with 998 receiving the vaccine and 1001 receiving placebo. Sixty-four cases of influenza-like illness were observed, of which, 44 were laboratoryconfirmed (12 in vaccine group versus 32 in placebo group). Vaccine efficacy was 62.5% (95%CI: 27.6-80.6) against all types of influenza and 63.3% (95%CI: 27.5-81.5) against influenza H3N2 illness. 11 severe adverse events reported (7 in LAIV group versus 4 in placebo group) were all deemed to be non-vaccine-related. Adverse events occurred in 412 (41.3%) participants in the vaccine group versus 389 (38.9%; p = 0.274) participants in the placebo group. Significant increase incidence of fever was observed in participants in the vaccine group, especially in those aged 3-9 years. Conclusions: The live attenuated influenza vaccine showed good efficacy and safety among 3- to 17-year-olds children during the 2016-2017 season at a site in eastern China. Clinical Trial Registry Number: NCT02964065. (C) 2020 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND-license (http://creativecommons.org/licenses/by-nc-nd/4.0/).