Immunogenicity and safety of a single intramuscular dose of a diphtheria-tetanus toxoid (Td) vaccine (GC1107) in Korean adults

The current study aimed to evaluate immunogenicity and safety of a newly developed diphtheria-tetanus toxoid (Td) vaccine, GC1107 (Green Cross Corporation, Yongin, Korea), in comparison with placebo and active comparator (licensed Td vaccine) in healthy Korean adults. A randomized, double-blind, placebo and active comparator-controlled study was conducted. Forty subjects were randomly administered a single intramuscular dose of GC1107, active comparator or placebo in a ratio of 2:1:1. At 2 and 4 weeks after vaccination, anti-diphtheria antibody levels in the GC1107 group increased 9.2 and 9.3 times, respectively, compared to predose titers. The corresponding values were 9.3 and 8.3 times for the active comparator group. Anti-tetanus antibody levels increased 39.0 and 37.9 fold at 2 and 4 weeks, respectively, after GC1107 administration, and 12.2 and 14.7 fold after active comparator administration. No increases in tetanus or diphtheria antibody were observed for the placebo group. Adverse events in the GC1107 and active comparator groups were more frequent than for the placebo group, but there were no significant differences between the two active treatments. In conclusion, GC1107 was well tolerated and provided significant boosts of anti-tetanus and anti-diphtheria antibodies.