A Phase II/III multicenter randomized single blind non-inferiority immunogenicity and safety study of TeddyVac™ vaccine of Human Biologicals Institute in healthy subjects of 10 years to 60 years of age.

Background: WHO and other health agencies recommend that tetanus toxoid (TT) should be replaced by tetanus-diphtheria (Td) vaccine taking into consideration the low coverage and waning immunity, especially for diphtheria. In this randomised, multicentre, non-inferiority study, the immunogenicity and safety of TeddyVac^™ vaccine of Human Biologicals Institute were compared with an existing brand.

Methods: The study involved 444 eligible subjects in two age groups at four centres across India. Group A included subjects of 18-60 years and Group B subjects of 10-18 years of age. All subjects received single dose of either TeddyVac^™ or the comparator vaccine as per randomisation. Blood samples for antibody titre estimation were collected before vaccination and 4-6 weeks after vaccination. Immunogenicity was assessed by estimating seroconversion rate, seroprotection rate, and geometric mean titres of antibodies. Safety was evaluated by collection and analysis of data on solicited and unsolicited adverse events.

Results: Overall, 441 subjects completed the study. Both the vaccine arms showed comparable seroconversion after a single dose for both the components. Both arms showed increase in seroprotection and geometric mean titres after a single dose of vaccination for both vaccine components, being significantly better for the diphtheria component in the test vaccine arm. Only few minor local and systemic adverse events were observed in both the vaccine arms. No serious adverse event was reported.

Conclusion: The study results indicate that the TeddyVac^™ vaccine is immunogenic, safe and non-inferior to the comparator Vaccine when administered to healthy subjects of 10 to 60 years of age.

Ctri registration number: CTRI/2021/07/035112.