Intradermal post-exposure rabies vaccination with purified Vero cell rabies vaccine: Comparison of a one-week, 4-site regimen versus updated Thai Red Cross regimen in a randomized non-inferiority trial in the Philippines

Vaccine. 2019 Apr 10;37(16):2268-2277. doi: 10.1016/j.vaccine.2019.02.083. Epub 2019 Mar 16.

Abstract

Background: Rabies post-exposure prophylaxis (PEP) via intradermal (ID) administration is standard practice in Asia. Accumulating evidence suggests that PEP shortened to 3 visits in one week does not adversely affect seroconversion rates or immune memory.

Objective: To determine whether the seroconversion rate at Day14 with a 1-week, 4-site (4-4-4-0-0) ID vaccination regimen with or without rabies immunoglobulin (RIG) was non-inferior to the updated Thai Red Cross (TRC) 28-day, 2-site (2-2-2-0-2) ID regimen with RIG during rabies PEP. We also assessed one-year antibody persistence.

Methods: This phase III, mono-center, open-label, randomized-controlled trial assigned participants aged ≤50 years (n = 600) exposed to suspected rabid animals and sustaining WHO Category II injuries (automatic allocation to G1) or Category III injuries (randomized to G2 or G3) to the following groups (1:1:1 ratio): G1 (n = 200), 1-week 4-site ID regimen with the purified Vero cell rabies vaccine (PVRV; Verorab®) without RIG; G2 (n = 201), 1-week 4-site ID regimen with PVRV, and purified equine rabies immunoglobulin (pERIG); G3 (n = 199), TRC 28-day, 2-site ID regimen with PVRV, and pERIG. Non-inferiority tests compared G1 vs. G3 and G2 vs. G3. Seroconversion rate was the proportion (%) of vaccinees with rabies virus neutralizing antibodies (RVNA) titers ≥0.5 IU/mL measured by rapid fluorescent focus inhibition test.

Results: On Day14, after the third vaccine administration, seroconversion rates were non-inferior in both comparisons and were, respectively, 100%, 99.4%, 98.8% in G1, G2, G3 with a decrease to 97.6%, 89%, 79.8% at Year 1. At Day14, RVNA geometric mean titers were 11.3 IU/mL; 9.89 IU/mL; 6.15 IU/mL, respectively, decreasing to 2.96 IU/mL, 1.37 IU/mL, 0.97 IU/mL at Year1. Safety and tolerability were similar between the three groups.

Conclusion: The seroconversion rate at Day 14 with the 1-week 4-site ID regimen, both with and without pERIG, was non-inferior to the reference TRC 28-day 2-site ID regimen with pERIG during rabies PEP with PVRV. ClinicalTrials.gov ID: NCT01622062.

Keywords: Intradermal regimen; Philippines; Purified Vero cell rabies vaccine; Rabies post-exposure prophylaxis; Verorab®.

Publication types

  • Clinical Trial, Phase III
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Animals
  • Child
  • Child, Preschool
  • Chlorocebus aethiops
  • Female
  • Humans
  • Immunization Schedule
  • Immunogenicity, Vaccine
  • Infant
  • Male
  • Middle Aged
  • Philippines / epidemiology
  • Post-Exposure Prophylaxis*
  • Rabies / prevention & control*
  • Rabies Vaccines / administration & dosage*
  • Rabies Vaccines / adverse effects
  • Rabies Vaccines / immunology*
  • Rabies virus / immunology*
  • Seroconversion
  • Thailand
  • Vaccination
  • Vero Cells
  • Young Adult

Substances

  • Rabies Vaccines

Associated data

  • ClinicalTrials.gov/NCT01622062