To assess the safety and immunogenicity of freeze-dried rabies vaccine (Vero-cells) for human use on different immunization procedures in healthy people aged 9-65 years.

A randomized, blind, positive-controlled clinical study was conducted in March 2015. The eligible residents aged 9-65 were recruited in Dengfeng city and Biyang County, Henan Province. A total of 1 956 subjects were enrolled. The subjects were randomly (1∶1∶1) assigned to 5-dose control group, 4-dose trial group and 5-dose trial group, with 652 subjects in each group. The subjects of 5-dose control group were immunized with control vaccine on days 0, 3, 7, 14 and 28. The subjects of 4-dose trial group were immunized with trial vaccine on days 0, 7 and 21 (2-1-1 phases) and the subjects of 5-dose trial group were immunized with trial vaccine on days 0, 3, 7, 14 and 28. A combination of regular follow-up and active reporting was used to observe local and systemic adverse reactions till 30 days after the first and full immunization, and the incidence rate of adverse reactions in three groups was analyzed and compared. The venous blood was collected before the first immunization, 7 days after the first immunization, 14 days after the first immunization and 14 days after the full immunization. The neutralizing antibody of rabies virus was detected by rapid fluorescent focus inhibition test (RFFIT), and the seropositive conversion rate and geometric mean concentration (GMC) of antibody were calculated.

The adverse reaction rates in 5-dose control group, 4-dose trial group and 5-dose trial group were 41.87% (273/652), 35.43% (231/652) and 34.97% (228/652), respectively. The adverse reaction rates of 4-dose trial group and 5-dose trial group were lower than those of the 5-dose control group (P<0.05). The local reactions were mainly pain, itching, swelling and redness in injection site, while the systemic reactions were mainly fever, fatigue, headache and muscle pain. The severity of adverse reactions was mainly mild (level 1), accounting for 85.33% (518/607), 89.02% (373/419) and 88.96% (427/480) of the total number of adverse reactions in each group. At 14 days after the first immunization and 14 days after the full immunization, the antibody positive conversion rates of three groups were all 100%. At 7 days, 14 days after the first immunization and 14 days after the full immunization, the GMCs of three groups were 0.60, 0.72, 0.59 IU/ml, 20.42, 23.99, 24.38 IU/ml and 22.95, 23.52, 24.72 IU/ml, respectively, with no significant difference (P>0.05).

The freeze-dried rabies vaccine (Vero-cells) for human use has good safety and immunogenicity when inoculated according to 5-dose and 4-dose immunization procedures.

Rabies vaccines; Randomized controlled trial; Immunization schedule; Safety; Immunogenicity