New acne vaccines enter trials as researchers pursue long-term cure and prevention

Two experimental vaccines could offer a safer, longer-lasting solution to acne, potentially preventing outbreaks rather than just treating them. One vaccine, being developed by Sanofi, uses an approach similar to mRNA vaccines to train the immune system to target bacteria linked to acne and is moving into human trials in the United States and Singapore.

Acne affects roughly one in five people at some point, and while most outgrow it by their mid-20s, at least 3 percent remain affected into their 30s and beyond, according to NHS estimates. Acne forms when hair follicles become blocked by sebum, an oily substance produced by glands near the skin surface, and dead skin cells create plugs that can become infected by bacteria that live on the skin. Treatments today include antiseptic or antibiotic creams to reduce bacteria, long courses of antibiotics, or isotretinoin, which shrinks the sebaceous glands and reduces sebum production but can cause very dry skin, loss of libido, mood changes and, in rare cases, suicidal thoughts. The spots can also return after drug treatment ends. The two vaccines in development could offer a safer and potentially more permanent solution.

One approach, being developed by Sanofi, uses technology similar to that used for Covid vaccines. It relies on fragments of genetic material derived from proteins found in Cutibacterium acnes, the family of bacteria linked to acne. After exposure to these proteins via a vaccine, the immune system would produce antibodies to attack the bacteria and shrink acne. The goal is for these antibodies to patrol the body for years, reducing the likelihood of acne returning. In animal tests, the vaccine limited the growth of acne-causing bacteria. Sanofi has begun recruiting 400 adults aged 18 to 45 with moderate to severe facial acne for a US trial, where participants will receive two shots followed by a booster after one year. A separate study involving 200 people with mild acne is planned in Singapore. Results from both trials are expected in 2027. It remains unclear whether the vaccine targets the specific C. acnes strains that cause acne or all six types found on the skin, a detail scientists say matters because some bacteria types are part of a healthy skin microbiome.

A separate vaccine project aims to prevent skin outbreaks by targeting an enzyme called hyaluronidase, which is secreted by acne-causing bacteria and helps acne form by breaking down hyaluronic acid, a skin substance that helps keep skin moisturized. In this approach, the enzyme is attached to an adjuvant to stimulate an immune response, and the resulting antibodies would attack hyaluronidase to disrupt the inflammatory process. A team at the University of California, San Diego, reported in Nature Communications in 2023 that a hyaluronidase-targeting vaccine reduced acne severity in mice by about half compared with controls. Researchers now plan early-stage human testing, with a realistically five-year horizon before such a jab might be available.

Experts say these therapies are in early-phase studies, but they could be offered in the future to people with a family history of acne and possibly help reduce long-term antibiotic use, a key driver of antibiotic resistance. Professor Alison Layton, a dermatologist and spokesperson for the British Association of Dermatologists, notes that while these novel approaches are still early, they raise the possibility of preventive vaccination for at-risk individuals. Dr Justine Hextall, a consultant dermatologist, cautions that it is not yet clear which C. acnes strains the vaccines would target, or how many strains contribute to acne risk, a detail that could influence microbiome balance. Dr Anshoo Sahota, another dermatologist, adds that experience with mRNA vaccines suggests such vaccines may wear off over time and could require regular boosters to maintain protection.

If these vaccines prove safe and effective, they could shift acne treatment away from long-term antibiotic use and toward prevention, potentially reducing the burden of acne for millions of people while addressing broader public health concerns about antibiotic resistance. Still, experts emphasize that widespread adoption would depend on demonstrating durable protection, understanding microbiome impacts, and establishing cost-effective delivery in healthcare systems. The timeline remains uncertain, with researchers stressing that even optimistic forecasts place a substantial wait before such vaccines reach routine clinical use.