AuthorisedPhase I and Phase II (Integrated)- First administration to humansInterventional

A Phase I/II, randomized, placebo-controlled, multi-arm, dose-finding study to evaluate the safety, efficacy and immunogenicity of an Acne mRNA vaccine candidate in adults with moderate to severe acne 18 to 45 years of age

Acne is a common skin condition that can cause painful, stubborn spots. While creams and tablets help many people, they do not work for everyone and can have unwanted side effects. This trial tests a new vaccine designed to help the body fight the inflammation and bacteria linked to acne. Because this is the first time the vaccine is being tested in humans, doctors need to check its safety very carefully. They will compare different doses of the vaccine against a dummy jab containing simple salt water. The study will look closely at any side effects, measure how the immune system reacts, and count whether the number of spots on the face decreases over time. Adults aged 18 to 45 with moderate to severe acne may be eligible to take part.

At a glance

Status

Authorised

Phase

Phase I and Phase II (Integrated)- First administration to humans

Sponsor

Sanofi Vaccines US Inc.

Enrolment target

189

Start

29 Jul 2026

Acne

What is this study about?

Acne affects millions of people across the UK. For many adults, it causes red, inflamed, and painful spots that can last for years and deeply affect self-esteem. Current treatments, such as long courses of antibiotics or strong prescription tablets, can cause unpleasant side effects and do not always provide lasting relief. This study is testing an entirely new approach: a vaccine designed to train the immune system to calm the inflammation and target the triggers that lead to severe breakouts.

The trial uses mRNA technology, similar to the science used in some modern flu and COVID-19 vaccines. The vaccine gives the body temporary instructions to build a harmless target protein. The immune system learns to recognise this protein and creates natural defences. In this study, scientists hope these defences will help keep acne-causing bacteria and skin inflammation under control.

Because this is an early-stage study (Phase I/II), it is the first time this vaccine is being given to people. The main priorities are to make sure the vaccine is safe, to find the best dose, and to see how well it works at clearing facial spots. To ensure fair and accurate results, participants will be randomly placed into groups receiving either the active vaccine or a harmless salt water injection (a placebo).

Doctors will carefully monitor small groups of volunteers first to check for any unexpected reactions before expanding the study. Over several months, researchers will count facial spots and run blood tests to see if the vaccine helps the skin clear up and how long the benefits might last.

Key takeaways

Researchers are testing a new mRNA acne vaccine in humans for the first time.
The study aims to check the safety of the vaccine and see if it helps clear moderate to severe facial acne.
Participants will be randomly assigned to receive either the vaccine or a salt water dummy injection.
The trial involves regular clinic visits, skin checks, and routine blood tests.
Taking part is completely voluntary, and you may withdraw at any time.

Who may be eligible?

This trial is open to adults aged 18 to 45 who have moderate to severe acne on their face. To take part, you must have active breakouts, including both inflamed red bumps and non-inflamed spots such as blackheads and whiteheads.

You should be in generally good health outside of your skin condition. You may not be able to take part if you are currently using certain prescription acne treatments, such as strong oral medications, or if you have had other recent vaccines. The trial team will review your full medication history to ensure it is safe for you to join.

Because this is an early-stage study, pregnant or breastfeeding women cannot take part. If you can become pregnant, you will be asked to use reliable contraception throughout the study to ensure safety.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

I am between 18 and 45 years of age.
I have moderate to severe acne on my face.
I am in generally good overall health.
I am not pregnant, breastfeeding, or planning a pregnancy during the study.
I am willing to attend regular clinic appointments and have routine blood tests.

Answer every question to see your result.

What does participation involve?

If you take part, you will be randomly assigned by a computer to receive either the new acne vaccine or an inactive salt water injection (placebo). Neither you nor the study doctors will know which one you receive during the test. You will receive the treatment as an injection, usually into the muscle of your upper arm. The trial is divided into phases, starting with small groups to carefully check safety before larger groups receive the injection.

You will need to attend regular clinic visits over several months. During these visits, doctors will check your blood pressure, take small blood samples, and examine your face to count your spots and see how your skin is healing. You will also be asked to keep a daily symptom diary for a short time after each injection to record any common reactions, like mild arm soreness or a slight fever. An optional long-term follow-up period may also be included to monitor your health over a longer time.

Potential risks and benefits

Taking part may help improve your acne, and you will receive close, expert medical attention for your skin throughout the study. However, because this is an early-stage trial, there is no guarantee that your skin will improve, and you might receive the inactive salt water injection. As with any new medicine, there is a risk of side effects. Common reactions may include redness, swelling, or aching where the needle went in, as well as mild flu-like symptoms such as tiredness, headache, or a mild temperature. Serious side effects are rare, but the medical team will watch you very closely. Taking part is completely voluntary, and you can withdraw from the study at any time without giving a reason and without affecting your everyday NHS medical care.

Locations (3)

Some site locations are approximate. We're improving this — please verify with the trial team before travelling.

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Unverified
Spain
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Unverified
Germany
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Unverified
Poland

Common questions

What is an mRNA vaccine?

An mRNA vaccine gives your body temporary, harmless instructions to make a specific protein. Your immune system spots this protein and builds natural defences against it, helping your body fight off the triggers of acne.

Will I definitely receive the acne vaccine?

No. This is a randomised study, meaning a computer randomly decides whether you receive the active vaccine or a dummy jab containing simple salt water.

Will I have to pay to take part?

No. Clinical trials in the UK do not charge participants. All study treatments, tests, and clinic appointments are free, and travel expenses are often reimbursed.

Can I continue using my normal acne face washes and creams?

The study team will give you clear instructions on which skin products you can use. You will likely need to pause certain medicated creams or strong treatments while taking part.

Can I leave the trial if I change my mind?

Yes. You are free to leave the trial at any point, for any reason. Your decision will not change how your regular doctors treat you.