Immunogenicity and safety of diphtheria-tetanus vaccine in pre-adolescent and adolescent South Koreans

Safety Profile of Recommended Vaccinations in Adolescents: Data from Surveillance of Adverse Events Following Immunization in Puglia (Italy), 2016-2020

Adolescence is a critical period for immunization, in which the adhesion rate to recommended vaccinations is often lower than desired. Since the safety of new vaccines is one of the most important factors determining vaccination hesitancy, post-marketing surveillance of adverse events following immunization (AEFIs) is recommended by the World Health Organization (WHO) to better understand the safety of these drugs. This report describes AEFIs notified in Puglia (Italy) after recommended vaccinations in adolescents aged 12 to 18 years in 2016–2020 to determine the safety profile of these products in a real-life scenario. This is a retrospective observational study. Data were gathered from the list of AEFIs notified in subjects between 12 and 18 years of age following administration of recommended vaccines in Puglia in 2016–2020. AEFIs were classified according to the WHO’s decisional algorithm, and causality assessment was carried out for serious AEFIs. From 2016 to 2020, 323,627 doses of vaccine were administered to adolescents in Puglia and 50 AEFIs were reported (reporting rate: 15.4 × 100,000 doses). Of these, 17 (34.0%) were classified as serious, and causality assessment identified 13 of them (76.5%) as vaccine related. The most common symptoms were local reactions, fever and neurological symptoms. No deaths were notified. The benefits of immunization in adolescents appear to be greater than the risk of AEFIs for all studied vaccines; in fact, AEFIs occur in less than 0.1‰ of patients and are generally mild and self-limiting.

A Phase III Study to Evaluate the Immunogenicity and Safety of GC1107 (Adult Tetanus Diphtheria Vaccine) in Healthy Adults

BACKGROUND

This study was conducted to assess the immunogenicity and safety of GC1107 (adult tetanus diphtheria [Td] vaccine). The primary goal was to evaluate the non-inferiority of the immunogenicity of GC1107 compared to the control vaccine. Additionally, the safety profiles of GC1107 and the control vaccine were compared.

METHODS

The subjects were adults ≥ 18 years old who were not injected with Td or adult tetanus-diphtheria-pertussis (TdaP) vaccine within the recent 5 years. A total of 253 subjects were enrolled and randomized to either the GC1107 group or the control group. For immunogenicity assessment, blood samples were collected at baseline and 28 days after vaccination and antibody titer of diphtheria and tetanus were assessed.

RESULTS

The seroprotection rates of diphtheria and tetanus were 89.76% and 91.34%, respectively, in the GC1107 group, and 87.80% and 86.99% in the control group. The geometric mean titer (GMT) of the anti-diphtheria antibody increased after vaccination in both groups, showing no significant difference between the groups (P = 0.139). The anti-tetanus GMTs after vaccination also showed comparable increases in both groups, and showed no significant difference (P = 0.860). In the safety evaluation, solicited local adverse reactions occurred in 81.2% of the subjects in the GC1107 group and in 86.4% of the subjects in the control group. Solicited systemic adverse events occurred in 33.2% of the subjects in the GC1107 group and in 47.2% of the subjects in the control group, which did not reach statistical significance.

CONCLUSION

This phase III study demonstrated non-inferiority in immunogenicity and comparable safety of GC1107 compared with the control Td vaccine.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02361866.

Immunogenicity and safety of the new reduced-dose tetanus-diphtheria vaccine in healthy Korean adolescents: A comparative active control, double-blind, randomized, multicenter phase III study

BACKGROUND/PURPOSE

A new reduced-dose tetanus-diphtheria (Td) vaccine was developed in Korea, and phase I and II clinical trials were successfully undertaken. We conducted this double-blind, randomized, multicenter phase III clinical trial to assess the immunogenicity and safety of the new Td vaccine.

METHODS

Healthy adolescents 11-12 years of age were enrolled and randomized to receive the new Td vaccine (study group) or a commercially available Td vaccine (control group). Blood samples were collected prior to and 4 weeks after the vaccination. Between the study and control groups, seroprotection rate, booster response, and geometric mean titer of antibodies against diphtheria and tetanus toxoids were compared after the vaccination. All solicited and unsolicited adverse events and serious adverse events during the 6-week study period were monitored.

RESULTS

A total of 164 adolescents received vaccination, and 156 of them were evaluated to assess immunogenicity. The seroprotection rate and geometric mean titer for antibodies against diphtheria were significantly higher in the study group, whereas those against tetanus were significantly higher in the control group. However, all seroprotection rates against diphtheria and tetanus in the study and control groups were high: 100% against diphtheria and tetanus in the study group, and 98.7% against diphtheria and 100% against tetanus in the control group. No significant differences in the frequency of solicited and unsolicited adverse events were observed between the two vaccine groups.

CONCLUSION

The new Td vaccine is highly immunogenic and safe, and this new Td vaccine can be effectively used for preventing diphtheria and tetanus.

Evaluation of immunogenicity and safety of the new tetanus-reduced diphtheria (Td) vaccines (GC1107) in healthy Korean adolescents: a phase II, double-blind, randomized, multicenter clinical trial

This phase II clinical trial was conducted to compare the immunogenicity and safety of a newly developed tetanus-reduced diphtheria (Td) vaccine (GC1107-T5.0 and GC1107-T7.5) and control vaccine. This study was also performed to select the proper dose of tetanus toxoid in the new Td vaccines. Healthy adolescents aged between 11 and 12 yr participated in this study. A total of 130 subjects (44 GC1107-T5.0, 42 GC1107-T7.5 and 44 control vaccine) completed a single dose of vaccination. Blood samples were collected from the subjects before and 4 weeks after the vaccination. In this study, all subjects (100%) in both GC1107-T5.0 and GC1107-T7.5 groups showed seroprotective antibody levels (≥ 0.1 U/mL) against diphtheria or tetanus toxoids. After the vaccination, the geometric mean titer (GMT) against diphtheria was significantly higher in Group GC1107-T5.0 (6.53) and GC1107-T7.5 (6.11) than in the control group (3.96). The GMT against tetanus was 18.6 in Group GC1107-T5.0, 19.94 in GC1107-T7.5 and 19.01 in the control group after the vaccination. In this study, the rates of local adverse reactions were 67.3% and 59.1% in GC1107-T5.0 and GC1107-7.5, respectively. No significant differences in the number of adverse reactions, prevalence and degree of severity of the solicited and unsolicited adverse reactions were observed among the three groups. Thus, both newly developed Td vaccines appear to be safe and show good immunogenicity. GC1107-T5.0, which contains relatively small amounts of tetanus toxoid, has been selected for a phase III clinical trial.

Influences on formation of tetanus antibody after simultaneous injection of tetanus immunoglobulin with tetanus vaccine

The goal of this study was to determine how much the formation of tetanus antibody is influenced after a single injection of tetanus vaccine (Td) and the simultaneous injection of tetanus vaccine with tetanus immunoglobulin (TIG). All of the healthy adult volunteers were divided into two groups: group 1 (Td only) and group 2 (Td plus TIG). Two hundred thirty seven volunteers were enrolled. When the baseline antibody titer, gender and age were adjusted, the geometric mean titers (GMTs) of the tetanus antibody (group 1 vs group 2) was 0.8438 IU/mL vs 0.5684 IU/mL at 4 weeks (P = 0.002), 0.4074 IU/mL vs 0.3217 IU/mL at 6 months (P = 0.072) and 0.3398 IU/mL vs 0.2761 IU/mL at 12 months (P = 0.140) after injection, respectively. The formation of tetanus antibody after tetanus vaccination is not influenced by TIG at the late period and in adults below the age of 50 yr, but there are significant differences between the two groups at the early period of 4 weeks after vaccination and for the patients over 60 yr.

Pentapeptide commonality between Corynebacterium diphtheriae toxin and the Homo sapiens proteome

Cross-reactivity may affect diagnostic tests and cause harmful autoimmune reactions following immunotherapy. To predict potential cross-reactivity and search for safe immunotherapeutic approaches, we analyzed sequence identity between microbial antigens and the human proteome. Using diphtheria toxin (DT) as a model, we examined its patterns of identity with human proteins at the pentapeptide level. DT shares 503 pentapeptides with the human proteome, while only 31 pentapeptides are unique to the toxin. DT pentapeptide identity involves multiple/repeated matches in human proteins (a total of 4966 occurrences). Human proteins containing bacterial peptide matches include antigens linked to fundamental cellular functions, such as cell cycle control, proliferation, development and differentiation. The data presented in this article offer a rational basis for designing peptide-based vaccines that specifically target DT and thus eliminate the potential risk of cross-reactivity with human proteins. More generally, this study proposes a methodological approach for avoiding cross-reactivity in immune reactions.

Immunogenicity and safety of diphtheria-tetanus vaccine in adults

This study was conducted to evaluate the immunogenicity and safety of diphtheria-tetanus (Td) vaccine in adults over 40 yr old who had never received a diphtheria-tetanus-pertussis (DTP) vaccination. A total of 242 subject completed three-doses of Td vaccination and subsequent assays for immunogenicity. Before vaccination, 33.9% and 96.7% participants showed antibody levels of diphtheria and tetanus, respectively, which were below protective level (<0.1 U/mL). After the first dose of Td vaccine, 92.6% and 77.6% of subjects gained protective antibody concentrations (≥ 0.1 U/mL) for diphtheria and tetanus, with an increase to 99.6% and 100% after the third dose. Local and systemic adverse events occurred in 37.9% and 15.5% of the subjects. No serious adverse event requiring an unscheduled hospital visit occurred. In conclusion, three-doses of Td vaccination to unimmunized adults are safe and effective in inducing protective immunity against diphtheria and tetanus.