Safety and immunogenicity of human rabies vaccine for the Chinese population after PEP: A systematic review and meta-analysis

AIM

To evaluate the safety and immunogenicity of rabies vaccine for human use after post-exposure in China.

METHODS

A systematic search was performed from PubMed, EMBASE, CNKI and Cochrane Library database, supplemented by manual retrieval. According to the inclusion and exclusion criteria, a meta-analysis was performed using Stata 16.0 software after independent literature screening, data extraction and quality assessment by two evaluators.

RESULTS

A total of 32 studies were included. It was found that rabies vaccination after PEP could induce the body to produce sufficient RVNA. Both Essen and Zagreb regimens showed good immunogenicity, with no significant difference in systemic events and local events after PEP, but a relatively high incidence of local and systemic events after PEP under the Zagreb regimen.

CONCLUSION

For the Chinese population, rabies vaccination after PEP has shown relatively a good immune efficacy and acceptable safety for preventing human rabies. The survey also found that the Zagreb regimen was comparable to the Essen regimen in terms of rabies prophylaxis with an acceptable safety profile.

Immunogenicity and safety of purified vero cell-cultured rabies vaccine under Zagreb 2-1-1 or 5-dose Essen regimen in the healthy Chinese subjects: a randomized, double-blind, positive controlled phase 3 clinical trial

Aim: The aims of the study were to evaluate the non-inferiority of the safety and immunogenicity of a new trial purified vero cell-cultured rabies vaccine (trial vaccine) in healthy subjects comparing with the control purified vero cell-cultured rabies vaccine (control vaccine) following Essen regimen and to evaluate the non-inferiority of the safety and immunogenicity of the trial vaccine following two intramuscular regimens, between Zagreb and Essen regimen. Methods: Serum samples were collected before vaccination and on d 7, 14, 35/42 post vaccination. Adverse events (AEs) were recorded for 30 d following each vaccination. This study was registered in the Chinese Clinical Trial Registry (ChiCTR-PPR-15007057). Results: There was no significant difference in the incidence of AEs, local and systemic reactions, among Zagreb group, Essen group, and control group. But the incidence of solicited AEs was a significant difference among the three groups (p = 0.0498). The incidence of solicited AEs was higher in Essen group than that in control group and Zagreb group (p = 0.0278, p = 0.0248). In the subjects whose antibodies were seronegative before vaccination, the seroconversion rates of antibodies among three groups were all 100.0% on d 14 and d 35/42. The Essen group was not inferior to the control group, and the Zagreb group was not inferior to the Essen group on d 14. On d 14 and d 35/42, the geometric mean concentration of the three groups was much higher than the immune protection level of 0.5 IU/ml. Conclusions: The trial vaccine had good safety and immunogenicity, and the trial vaccine is not inferior to the control vaccine. Abbreviations: PVRV: purified vero cell-cultured rabies vaccine; AE: adverse event; CI: confidence interval; GMC: geometric mean concentration; IM: intramuscular; NIFDC: National Institutes for Food and Drug Control; PPS: per-protocol set; SS: safety set; REFIT: Rapid Fluorescent Focus Inhibition Test; RVNA: rabies virus neutralizing antibody; WHO: World Health Organization.

Immunogenicity and safety of purified vero cell rabies vaccine (PVRV) produced by Liaoning Cheng Da Co. under Zagreb 2-1-1 or 5-dose Essen regimen in Chinese adults aged 50 and above

BACKGROUND

Two kinds of regimens (2-1-1 and 1-1-1-1-1) can be selected after Zagreb regimen(2-1-1)of PVRV was officially approved in Beijing in January 2015. Up to now, the subjects for most studies about the comparison between Zagreb and Essen regimen are under 50 y old, rarely at and above. Aging of the immune system may result in decreasing efficacy of vaccination, especially for adults aged above 65-70 y. This study compared the safety and immunogenicity of the Zagreb and Essen regimen in Chinese adults aged 50 and above with the goal to provide a supplemental data for this age group.

METHODS

A total of 114 cases were divided into 2 groups randomly, received PVRV under the Zagreb and Essen regimens respectively. Serum samples were collected at D0, D7, D14, D42, D180 and D365 to determine the rabies serum neutralizing antibody by rapid fluorescent focus inhibition test (RFFIT). Safety analyses were made by comparing the AEs in day-3, day-7, and day-(7 + 21) in Zagreb or day-(7 + 28) in Essen by gender and age cohorts.

RESULTS

617 blood samples were obtained. Two groups showed similar immunogenicity, the neutralizing antibody titer of all subjects at D14 and D42 showed >0.5 IU/ml. Under the same regimen, Subjects ≥65 y had lower GMC than those who <65 years from D7 to D365 within 2 groups. This difference was significantly shown on D7, D14, D180 in Zagreb group, and on D180 in Essen group (t = 2.38, p = 0.02; t = 3.78, p < 0.001; t = 2.30, p = 0.03; t = 4.42, p < 0.001). Subjects<65 years had higher seroconversion rate compared to ≥65 y on D7, D180 and D365 in both 2 groups, this difference was also significantly shown on D180, D365 in Zagreb group and on D180 in Essen group (χ² = 20.66, p < 0.001; χ² = 6.56, p = 0.02; χ² = 10.96, p = 0.002). Two regimens all showed favorable performances with mildly or common adverse events (AEs). The incidence of local AEs after 3 d in Essen group was higher than Zagreb group (χ² = 9.69, p = 0.002). The most common local AE was pain, the incidences (8.8%) in Zagreb group was higher than Essen group (8.4%, χ² = 5.12, p = 0.02). All AEs for Zagreb group and 52.3% of AEs for Essen group occurred during the first 72 hours. During the first 72 hours, subjects aged <65 in Zagreb group (16.26%) had higher incidences of AEs than Essen group (8.57%, χ² = 4.54, p = 0.03), males in Zagreb group (16.05%) had higher incidence of AEs than Essen group (5.71%, χ² = 5.34, p = 0.02). The incidences of AEs close in during the first 7 d.

CONCLUSION

The Zagreb and Essen regimens demonstrated the similar safety and efficacy of PVRV in Chinese adults aged 50 and above. People ≥65 y showed reduced immune response to both regimens. More AEs for the Zagreb regimen were observed within the first 72 hours, especially for male and people < 65 y.

A randomized open-labeled study to demonstrate the non-inferiority of purified chick-embryo cell rabies vaccine administered in the Zagreb regimen (2-1-1) compared with the Essen regimen in Chinese adults

The Zagreb regimen has been used for 20 years in various countries. In China, until 2010, the Zagreb schedule was only approved for purified chick embryo cell vaccine (PCECV) and purified Vero cell rabies vaccines (PVRV). In this phase III clinical trial, we aimed to demonstrate the safety and immunogenic non-inferiority of the Zagreb regimen compared with the Essen regimen in healthy adult Chinese immunized with PCECV (Rabipur®). The study enrolled 825 subjects aged 18 to 50 years; serum samples were collected on Days 0, 7, 14, 42, and at 13 months to assess rabies virus neutralizing antibody (RVNA) concentrations. Solicited and unsolicited local and systemic reactions were recorded for 6 days following the day of vaccination, and collected throughout the entire study period (Day 1 until Month 13). The Zagreb regimen was non-inferior to the Essen regimen with regard to RVNA concentrations after 7, 14, and 42 days, and 13 months of immunization. The non-inferiority of seroconversion was established at Days 14 and 42. The incidence of local and systemic reactions was similar between groups, and mostly of mild or moderate severity. Vaccine-related adverse events occurred more frequently in the Essen group than in the Zagreb group. Vaccination with PCECV under a 2-1-1 regimen is as safe and immunogenic as under the traditional 5-dose Essen regimen for rabies post-exposure prophylaxis, and is a more cost-effective option, has a more practical vaccination schedule, and can potentially increase compliance.

Immunogenicity and safety of purified chick-embryo cell rabies vaccine under Zagreb 2-1-1 or 5-dose Essen regimen in Chinese children 6 to 17 years old and adults over 50 years: a randomized open-label study

The aim of this Phase IIIb, open-label, randomized study was to demonstrate the non-inferiority of immune responses and to assess the safety of a purified chick-embryo cell rabies vaccine (PCECV) in healthy Chinese children (6 to 17 years) and older adults (≥51 years) following 2 alternative intramuscular (IM) simulated post-exposure prophylaxis (PEP) regimens: 4-dose Zagreb or 5-dose Essen regimen. Serum samples were collected prior to vaccination on Days 1 and 15 and on day 43 to assess immune response by rabies virus neutralizing antibody (RVNA) concentrations. Solicited adverse events (AEs) were recorded for up to 7 days following each vaccine dose, and unsolicited AEs throughout the entire study period. PCECV vaccination induced a strong immune response at Day 15, and the non-inferiority in immune response of the Zagreb vs. the Essen regimen was demonstrated in children and older adults. At Day 15,100% of children (N = 224), and 99% of subjects ≥51 years of age (N = 376) developed adequate RVNA concentrations (≥0.5 IU/mL); at Day 43 all subjects achieved RVNA concentrations ≥0.5 IU/mL, for both PEP regimens. The well-known tolerability and safety profile of the PCECV was again observed in this study following either Zagreb or Essen regimens. Rabies PEP vaccination with PCECV following a Zagreb regimen induced immune responses non-inferior to those of the Essen regimen, and had a similar safety and tolerability profile to the Essen regimen in Chinese children, adolescents, and adults over 51 years. ClinicalTrials.gov identifier: NCT01680016.

Comparison of safety and immunogenicity of purified chick embryo cell vaccine using Zagreb and Essen regimens in patients with category II exposure in China

The aim was to compare the safety and immunogenicity of purified chick embryo cell vaccine (PCECV) with Zagreb 2-1-1 and Essen 1-1-1-1-1 regimens in patients with WHO category II exposure in China. Side effects including systemic and local symptoms were recorded for all patients during vaccination with purified chick embryo cell vaccine (PCECV) under Zagreb 2-1-1 or Essen 1-1-1-1-1 regimens, and the rabies neutralization antibody titers in patients' serum at days 0, 7, 14, 45, 365 post-immunization were measured to determine the immunogenicity. Fever and pain were the most common events for systemic and local symptoms respectively, and most side effects (86.78%, 105/121) occurred after the first dose of vaccination. Safety analysis showed differences in side effects in<5-year-old patients between Zagreb and Essen regimens, especially after the first dose of vaccination (P = 0.043). Immunogenicity analysis indicated that Zagreb can achieve higher neutralization antibody titers and a greater seroconversion rate in a shorter time but had less persistence than Essen. When compared with the Essen regimen, the Zagreb regimen had a different immunogenicity in all study subjects, and different safety profile in young children, and a further study with a larger population and longer surveillance is warranted.