Recipient organisationNIHR Southampton Biomedical Research Centre
NIHR supportRecorded as supported by this research centre
PeriodFeb 2025 — Mar 2026
In plain English
AI plain-English summary
A 60-person trial in England will test whether a fridge-free tetanus and diphtheria booster shot works as well as the standard cold-chain vaccines. Most vaccines must be kept cold from factory to needle, a requirement that strains supply chains in hot climates, remote areas, and emergency settings. SPVX02 is a freeze-dried formulation designed to survive storage at room temperature. This Phase 1 study will compare its safety and immune response against two licensed boosters in healthy adults aged 18–55 who have not had a booster in the past decade. If SPVX02 proves safe and immunogenic, it could simplify vaccine logistics globally. Cold-chain failures cause vaccine spoilage and missed doses; a thermostable shot would reduce waste, cut transport costs, and make booster campaigns easier to run in low-resource settings. The study is a first-in-human safety and immunogenicity trial, so practical impact remains years away. But the principle—stabilising a complex biological product without refrigeration—could extend beyond tetanus and diphtheria to other vaccines that currently depend on uninterrupted cold storage.
View original technical description
Stablepharma is developing a thermostable lyophilized tetanus and diphtheria (Td) vaccine (SPVX02) based on a reformulation of Tetadif® vaccine. This Phase 1, first-in-human study will be run at NHS sites in England and aims to evaluate the safety, immunogenicity and tolerability of SPVX02 whilst also providing comparative immunogenicity data with Tetadif® and diTeBooster® (comparator investigational medicinal products) using a randomised, single-blind design. The study aims to demonstrate that SPVX02, Tetadif and diTeBooster generate comparable anti-tetanus and anti-diphtheria post-boost immune responses in healthy adults. The study will be conducted in 60 healthy participants (aged 18-55) who have previously received a primary vaccination against tetanus and diphtheria but who have not received a booster vaccination in the last 10 years. Three cohorts of 20 participants will be randomised 1:1:1 in a single-blind manner to receive a single vaccination of either SPVX02, Tetadif or diTeBooster. The primary objectives of the study are to evaluate the safety of a single vaccination of SPVX02 and to evaluate the tolerability of a single dose of SPVX02, Tetadif or diTeBooster. The secondary objectives are to evaluate post-dose antibody titres to obtain immunogenicity data (seroprotection and seroconversion rates). Informed consent will be obtained before any study specific procedures are performed. Participants will be screened from Day -42 to Day 0. Eligible participants will attend the clinic to receive a single dose of SPVX02, Tetadif or diTeBooster on Day 1. On Day 1, an electronic diary , tape measure and thermometer will be provided to perform self-assessments of local and systemic safety and tolerability up to, and including, Day 7. All participants will have a follow-up telephone call on Day 2 and return to the clinic for study assessments on Days 7 and 28. End of study visit procedures will be performed at the final clinic visit on Day 28.
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