Safety and immunogenicity of chromatographically purified Vero cell rabies vaccine for intradermal pre- and post-exposure rabies prophylaxis

Abstract

Improved rabies pre- and post-exposure prophylaxis (PrEP and PEP) in developing countries uses an economic multi-site intradermal vaccination. Aim: To evaluate immunogenicity of chromatographically purified Vero cell vaccine (CPRV) for intradermal PrEP and PEP. Method: The subjects received conventional PrEP with CPRV or PVRV in PrEP study or received intradermal PEP with CPRV or PVRV and rabies immunoglobulin in PEP study. Result: All subjects who received PrEP with CPRV had protective neutralizing antibody (Nab) titers (≥0.5 IU/ml) 14 days after completing vaccination. In PEP study, Nab titers in the CPRV groups reached ≥ 0.5 IU/ml in all subjects by day 14 through day 90 after vaccination. The geometric mean titers of Nab in the CPRV groups had significantly higher titers than the PVRV group on day 14 through day 365 (p < 0.05). No serious adverse reactions were observed. Conclusions: CPRV is safe and immunogenic when given for intradermal PrEP and PEP.

Keywords::

• intradermal injection
• post-exposure prophylaxis
• pre-exposure prophylaxis
• rabies vaccine

Acknowledgement

The authors express our gratitude to our supervisor, Professor Visith Sitprija and all the members of the advisory committee. We would like to thank veterinary students, our volunteers, the dean and faculty of Veterinary Science of Mahanakorn University of Technology for their cooperation. Without all their knowledge and assistance, this study would not have been successful.

Financial & competing interests disclosure

This study was financially supported by Liaoning Cheng Da Biotechnology Company in China. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Rabies pre- and post-exposure prophylaxis in developing countries uses an economic multisite intradermal vaccination (such as TRC-ID regimen; 2-2-2-0-2-0) using less cell-culture rabies vaccine compared with intramuscular vaccination.

• This prospective study assessed the safety and immunogenicity of conventional intradermal pre- and post-exposure prophylaxis using the chromatographically purified Vero-cell vaccine (CPRV) compared with purified Vero-cell vaccine (PVRV).

• Our study of pre-exposure prophylaxis showed that CPRV is at least as immunogenic as PVRV in terms of seroprotection rates (≥0.5 IU/ml) 14 days after the third dose of a conventional pre-exposure vaccination.

• Our study of conventional intradermal post-exposure regimen revealed that all subjects who received CPRV concurrently with equine rabies immunoglobulin had rabies neutralizing antibody above protective level (0.5 IU/ml) on days 14, 28 and 90 after vaccination.

• No serious adverse reactions were observed after administration of CPRV.

• The CPRV is safe and immunogenic as WHO-approved cell-culture vaccine when given in conventional intradermal pre- and post-exposure prophylaxis.