Safety and immunogenicity of purified vero cell rabies vaccine versus purified chick embryo cell rabies vaccine using pre-exposure and post exposure regimen among healthy volunteers in San Lazaro Hospital

ABSTRACT

OBJECTIVE: This is a prospective, randomized open-labeled clinical study to demonstrate the safety and immunogenicity of Purified Vero Cell Rabies Vaccine (PVRV) Freeze-Dried using pre-exposure and post- exposure regimen utilizing Modified Thai Red Cross schedule (Modified TRC) in comparison with Purified Chick Embryo Cell (PCEC) Rabies Vaccine among healthy volunteers in San Lazaro Hospital.METHODOLOGY: A total of 189 healthy Filipino volunteers were randomized into three groups Group A received PVRV 0.1 ml intradermally (ID) using the pre-exposure regimen (Day 0, 7, 28). Group B and Group C were given PVRV 0.1 ml ID and PCEC 0.1 ml ID, respectively, using the Modified TRC on days 0, 3, 7 and 30. The statistical tables and graphs were generated using Microsoft® Excel® 2010. SPSS® version 13 for Windows™ was used for descriptive statistics (geometric mean, arithmetic mean, standard deviation and percentages) and inferential statistics (?2 test, one-way ANOVA and two-way mixed factorial ANOVA).RESULTS: The results revealed that the percentage seroconversion of both PRVR and PCEC post-exposure groups in this clinical study were 100% on days 14 and 90. The PRVR pre-exposure group achieved 96% seroconversion on Day 28 with Geometric Mean titers (GMT) of 1.96 IU/ml (95% CI 1.45 - 2.65), which is comparable to other similar studies on pre-exposure rabies vaccination. There was no overall difference in all three groups for the whole duration of the study (p = 1.000). The geometic mean titers (GMT) for post-exposure PRVR and PCEC groups on days 14, 30 and 90 were all above 0.5 IU/ml. There was no significant difference between these two post-exposure groups (p = 0.052). The proportion of the subjects in the three groups who experienced local (pain and tenderness at the injection sites, erythema and itching) or systemic reactions (low grade fever, dizziness and headache) during follow-up period were not significantly different (p = 0.134). There were no serious adverse events (SAEs) reported during the follow-up period.CONCLUSION: The Asian manufactured PVRV is safe, tolerable, immunogenic and comparable with PCEC and therefore, the Asian manufactured PVRV can be an economical alternative for rabies post-exposure treatment using the modified TRC regimen and for pre-exposure prophylaxis.