The purpose of this research study is to check whether the MNS Miracus Patch (the study's investigational device, a small patch made up of microneedles that dissolve in the skin and can potentially deliver vaccines in a pain-free way) is safe to use and tolerated by humans when administered for 10 minutes, both as a plain patch (with no vaccine) and as a loaded patch (with the tetanus- containing vaccine included). This study will also investigate whether the patch delivers the correct dose of the vaccine in the loaded patches by checking the immune response of participants.

As the device has not been tested clinically in humans before, this will be a first-in-human study involving healthy participants only, who have not previously received the full course of tetanus diphtheria vaccinations. This research study will take approximately 4-6 weeks of the participants' time.

The study consists of a screening period up to 2 weeks to determine if participants are eligible for the study. Upon confirmation of eligibility, participants will enter the 'double-blind' study where they will receive one patch in clinic.

Double-blind means that neither the participant nor the study doctor will know if the individual is receiving the empty or loaded patch. Participants will be randomly selected to receive the empty or loaded patch, and the number of participants will be equal in each group.

During the study, participants will be asked to complete questionnaires, have photographs taken of their skin, give blood and urine samples and undergo general health checks including physical exam and vital signs.

The clinical trial is funded by Microneedle Solutions Ltd. And Innovate UK, and will recruit 30 participants at one site in the UK only.

Inclusion Criteria:

• Healthy male or female adults aged >16 years.
• Minimum 27x27mm patch of hairless skin on the upper flexor forearm that is not affected by any clinically significant dermatological condition at the intended application site (upper flexor forearm), including but not limited to active inflammatory dermatoses (e.g., eczema, psoriasis), infection (bacterial, viral, or fungal), scarring or keloids, sun or chemical burn, pigmentary disorders that may interfere with assessment, autoimmune or bullous disease, vascular or purpuric lesions, open wounds, tattoos at the application site, or any other skin abnormality that, in the opinion of the Investigator, could interfere with study assessments or increase risk to the participant.
• Able to provide written informed consent.
• Postmenopausal women aged 45 and above who have not had a period for at least 12 months and are not using hormonal contraception.
• Females of child-bearing potential must agree to use medically approved methods for birth control including condoms with or without spermicides, hormonal contraceptives (oestrogen and/or progestin products; either oral, intrauterine, or epidermal) or intrauterine device with copper.

Willing to comply with all study procedures and attend all scheduled visits.

Exclusion Criteria:

• Known allergy or hypersensitivity to Tetanus containing vaccine or any skin-contacting components of the Miracus™ patches (polyvinylpyrrolidone (PVP), Polycarbonate (PC), acrylic and/or silicone).
• Prior Tetanus Containing Vaccine booster within the last 12 months. .
• Participation in another IMP clinical trial within the last 30 days.
• Use of systemic immunosuppressive or immunomodulatory medication within 30 days prior to first study intervention, including but not limited to systemic corticosteroids (≥10 mg/day prednisone equivalent for >14 days), biologic agents, monoclonal antibodies, calcineurin inhibitors, antimetabolites, cytotoxic agents, or JAK inhibitors, or any other systemic or topical medications that, in the opinion of the investigator, may affect skin condition or immune response. - - Topical, inhaled, or intranasal corticosteroids are permitted if, in the opinion of the Investigator, they are not expected to result in clinically meaningful systemic immunosuppression.
• Evidence of active systemic infection, defined as clinically significant abnormalities in haematology, inflammatory markers (e.g., elevated WBC count or CRP), positive infection serology, or other laboratory findings consistent with acute infection, as determined by the Investigator.
• Pregnant or lactating female, or pregnancy planned during the trial.
• Presenting a psychological or linguistic incapacity to understand and sign the informed consent form.
• Employees of the Sponsor or study site who are directly involved in the design, conduct, oversight, or analysis of the study, and their immediate family members. Other hospital or institutional staff not involved in the study may participate, provided there is no direct supervisory or dependent relationship with study personnel.

The study is double-blind. The only unblinded personnel on the study are the Sponsor's manufacturing team who will have no direct study involvement, and an unblinded statistician who will prepare the randomisation list.