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

Headache After Vaccination: An Update on Recent Clinical Trials and Real-World Reporting

PURPOSE OF REVIEW

The aim of this review is to characterize headache as a vaccine adverse event (VAE) in clinical trials.

RECENT FINDINGS

Of the recent phase III vaccine RCTs (non-COVID-19), 53 studies reported on headache (13 infectious agents). The median rate (interquartile range) of headache was 15.6% (IQR: 9.6-37.6%). Of these, 24.5% of the RCTs reported headache greater in the vaccine group compared to the placebo/control group. In the herpes zoster vaccination trials, headache was more common in all active groups: median rate 33.9% (IQR: 29.7-40.5%) as compared to placebo: median rate 17.7% (IQR: 15.4-23.8%). Influenza and HPV vaccination trials were the 2nd and 3rd most common to have headache as a VAE. Of the 6 widely distributed COVID-19 vaccinations, median rate of post-vaccination headache was 39% (IQR: 28-50%). Headache is a common VAE in vaccine trials. Standardized grading methods, predictors of persistence, and treatment regimens are warranted.

Immunogenicity and Safety of a Newly Developed Tetanus-Diphtheria Toxoid (Td) in Healthy Korean Adolescents: a Multi-center, Randomized, Double-blind, Active-Controlled Phase 3 Trial

BACKGROUND

Although the combination tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis vaccine (Tdap) is recommended at adolescence in developed countries, the tetanus and diphtheria toxoid vaccine (Td), which is less costly, is recommended instead in some parts of the world. A new Td, BR-TD-1001, was developed by a Korean manufacturer for distribution to endemic regions and for use in the initial step of novel Tdap development.

METHODS

This phase 3, randomized, double-blind, multi-center trial, conducted in Korea, aimed to evaluate the immunogenicity and safety of BR-TD-1001. Healthy children aged 10 to 12 years were randomized 1:1 to receive either BR-TD-1001 or the control Td (Td-pur, GlaxoSmithKline). Antibodies were measured using enzyme-linked immunosorbent assay.

RESULTS

A total of 218 subjects (BR-TD-1001, n = 108; control, n = 110) were enrolled and included in the safety analysis. Vaccine-mediated antibody responses were similar in both groups. We confirmed the non-inferiority of BR-TD-1001 against the control, Td; 100% of both groups achieved seroprotection against diphtheria and tetanus. Furthermore, there was no significant difference between groups in the proportion of participants who demonstrated boost responses against diphtheria and tetanus toxoids. The incidence of solicited local and systemic adverse events (AEs), unsolicited AEs, and serious AEs did not differ significantly between groups.

CONCLUSION

The BR-TD-1001 satisfied the immunological non-inferiority criterion against diphtheria and tetanus, with a clinically acceptable safety profile.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04618939.

Immunogenicity and Safety of a Tetravalent Dengue Vaccine Administered Concomitantly or Sequentially With Tdap Vaccine: Randomized Phase IIIb Trial in Healthy Participants 9-60 Years of Age in the Philippines

BACKGROUND

Incorporating dengue vaccination into existing childhood vaccination programs could increase vaccine coverage. This study assessed the safety and immunogenicity of concomitant versus sequential administration of the combined tetanus toxoid, reduced diphtheria toxoid and acellular pertussis (Tdap) vaccine and the tetravalent dengue vaccine (CYD-TDV).

METHODS

This phase IIIb, randomized, open-label, multicenter study was conducted in the Philippines in individuals 9-≤60 years of age (NCT02992418). Participants were to receive 3 CYD-TDV doses 6 months apart, the first dose administered either concomitantly or sequentially (28 days post-Tdap). Antibody levels were measured at baseline and 28 days post-first doses of Tdap vaccine and CYD-TDV, using enzyme-linked immunosorbent assay (pertussis, tetanus), micrometabolic inhibition test-toxin neutralization assay (diphtheria) and plaque reduction neutralization test (dengue). Immunogenicity was assessed for all participants, and statistical analysis reported for baseline dengue seropositive participants. Safety was assessed throughout.

RESULTS

Among 688 randomized participants, 629 (91.4%) were baseline dengue seropositive (concomitant group, n = 314 and sequential group, n = 315). After the first dose, non-inferiority of immune responses between concomitant and sequential vaccination was achieved; between-group geometric mean antibody concentration ratios were close to 1 for anti-PT, anti-FHA, anti-PRN and anti-FIM, between-group differences in percent achieving seroprotection (titers ≥0.1 IU/mL) were 0.26% (diphtheria) and 0.66% (tetanus), and between-group geometric mean antibody titer ratios were close to 1 for dengue serotypes 1-4. Safety profiles in both study groups were comparable.

CONCLUSIONS

CYD-TDV and Tdap vaccine administered concomitantly or sequentially in baseline dengue seropositive participants elicited comparable immunogenicity and safety profiles.

Factors Influencing Persistence of Diphtheria Immunity and Immune Response to a Booster Dose in Healthy Slovak Adults

We assessed the long-term persistence of humoral immunity against diphtheria in adults with childhood vaccination and the immunogenicity of a booster dose considering demographic, behavioural and vaccinating factors. We conducted a trial in 200 healthy Slovak adults aged 24–65 years, immunised against diphtheria in childhood and against tetanus at regular 10–15 year intervals, and receiving a dose of a tetanus-diphtheria toxoid vaccine. The response was determined by ELISA antibody concentrations of paired sera before and at 4 weeks post-vaccination. A seroprotection rate of 21% (95% confidence interval, CI 15.6–27.3%) was found in adults up to 59 years since the last vaccination with seroprotective levels of antibodies against diphtheria ≥0.1 IU/mL and a geometric mean concentration of 0.05 IU/mL. Conversely, seropositive levels ≥0.01 IU/mL were observed in 98% of adults (95% CI 95–99.5%). Booster-induced seroprotection was achieved in 78% of adults (95% CI 71.6–83.5%) clearly depending on pre-booster antibody levels correlating with age and time since the last vaccination. Moreover, only 54.2% of smokers and 53.3% of patients on statins exhibited seroprotection. Booster vaccination against diphtheria was unable to confer seroprotection in all recipients of only childhood vaccination.