Rabies is caused by rabies virus with a 100% mortality rate in humans. Most of cases occur in Africa and Asia, mainly in underserved populations. Rabies is a vaccine-preventable disease in both humans and animals. Over the years, the Vero cell rabies vaccine has been recognized by the World Health Organization (WHO) and the European Union, and is widely used globally. Currently, one of the post-exposure prophylaxis (PEP) regimens recommended by the World Health Organization (WHO) is the five-dose "Essen" regimen (1-1-1-1-1), involving one intramuscular dose administered on days 0, 3, 7, 14, and 28 respectively. This clinical trial was to assess the immunogenicity and safety of a freeze-dried human rabies vaccine (Vero Cell) in healthy population for the large-scale developing, and explore the booster vaccination.
Rabies is caused by rabies virus with a case fatality rate approaching 100% in humans. Studies reported that about 59000 human deaths and over 3.7 million disability-adjusted life years lost every year. Most of cases occur in Africa and Asia, mainly in underserved populations, with approximately 40% of cases in children aged \<15 years. Fortunately, rabies is a vaccine-preventable disease in both humans and animals. Post-exposure prophylaxis (PEP), is the critical intervention for preventing the onset of the disease. Conventional Vero cell rabies vaccines have been used globally for decades, demonstrating excellent safety and immunogenicity. However, their production typically requires the use of animal-derived components, such as fetal bovine serum or human serum albumin, in the cell culture medium. This practice raises potential concerns regarding the risk of contamination with adventitious agents, batch-to-batch variability, and the potential for allergic reactions. To address these limitations, a new generation of purified Vero rabies vaccine produced in serum-free medium has been developed. This vaccine uses the same Pitman-Moore virus strain as the traditional vaccines but is manufactured without any human or animal serum-derived components, significantly reducing the risk of extraneous protein contamination and representing a substantial advancement in vaccine technology and safety. The shift to a serum-free production process, while a clear advantage for safety, raises critical questions regarding the vaccine's immunogenicity and the duration of protection it confers. This study aims to systematically evaluate the available evidence of the serum-free Vero cell rabies vaccine. First, we will critically assess its immunogenicity in PEP settings. Second, we will assess the long-term persistence of protective antibody titers following primary vaccination. Finally, we will discuss the rationale for and evidence on booster vaccination strategies.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
TRIPLE
Enrollment
1,200
The tested vaccine is a lyophilized human rabies vaccine (Vero Cells) produced by Shanghai Rongsheng Biotech Co., Ltd.
The control vaccine is a lyophilized human rabies vaccine (Vero Cells) produced by Liaoning Chengda Biotechnology Co., Ltd.
Pizhou county Center for Disease Control and Prevention
Pizhou, Jiangsu, China
Seroconversion rate of rabies virus-specific neutralizing antibodies (RFFIT) in pre-immunization seronegative subjects.
Percentage of participants with rabies virus neutralizing antibody concentration ≥0.5 IU/ml, the experimental group is non-inferior to the control group, non-inferiority margin for seroconversion rate:-5%.
Time frame: 14 days following the 5 doses full-course immunization
Geometric mean concentration (GMC) of rabies virus-specific neutralizing antibodies in pre-immunization seronegative subjects.
GMC, concentration of participants with rabies virus neutralizing antibody concentration, the experimental group is non-inferior to the control group, non-inferiority margin for GMC ratio:0.67.
Time frame: 14 days following the 5 doses full-course immunization
Seroconversion rate of rabies virus-specific neutralizing antibodies (RFFIT) in pre-immunization seronegative subjects.
Seroconversion rate, percentage of participants with rabies virus neutralizing antibody concentration ≥0.5 IU/ml, the experimental group is non-inferior to the control group, non-inferiority margin for seroconversion rate:-5%.
Time frame: 14 days following the first dose
Geometric mean concentration (GMC) of rabies virus-specific neutralizing antibodies in pre-immunization seronegative subjects.
GMC, concentration of participants with rabies virus neutralizing antibody concentration, the experimental group is non-inferior to the control group, non-inferiority margin for GMC ratio:0.67.
Time frame: 14 days following the first dose
Percentage of participants with rabies virus neutralizing antibody concentration ≥0.5 IU/ml or increase by 4 folds after vaccination
Time frame: 7、14 days post the first dose and 14 days post the 5 doses full-course immunization
Geometric mean concentration (GMC) of rabies virus-specific neutralizing antibodies
Time frame: 7、14 days post the first dose and 14 days post the 5 doses full-course immunization
Percentage of participants with rabies virus neutralizing antibody concentration ≥0.5 IU/ml after vaccination.
Time frame: Month 3、6、12 following the 5 doses full-course immunization
GMC of rabies virus neutralizing antibody
Time frame: Month 3、6、12 following the 5 doses full-course immunization
Proportion of subjects reporting adverse events
Time frame: Day 30 post-each dose
Proportion of subjects with Serious Adverse Events occurring throughout the trial
Time frame: Day 0 up to month 12 following the full-course immunization
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