Headlines about a breast cancer vaccine appear every few months, and they leave many people asking the same questions: does it exist, can I get it, and is it for me? The short answers are that no breast cancer vaccine is approved yet, several are being tested in clinical trials right now, and the only way to receive one today is by taking part in a study. This guide explains what a cancer vaccine is and how it differs from the vaccines most people know, what the much reported Cleveland Clinic vaccine has and has not shown, which other approaches are being studied, and who these trials are looking for.
Interested in a breast cancer vaccine?
No breast cancer vaccine is approved yet, and clinical trials are currently the only way to receive one.
How a cancer vaccine works
Most vaccines, such as flu or measles vaccines, train the immune system to recognize a germ. Cancer vaccines instead train it to recognize proteins found on cancer cells, so that the body can attack those cells or stop them from growing back. They come in two broad kinds. Preventive vaccines aim to stop cancer from developing or returning in people at high risk, such as those who have finished treatment or who carry a high risk gene. Treatment vaccines are given to people who have cancer, usually alongside other treatments, to strengthen the immune response against it. There are already vaccines that prevent certain cancers, such as the HPV and hepatitis B vaccines, but they work by preventing a virus, and breast cancer is not caused by a virus, which is why a breast cancer vaccine has to work differently.
The Cleveland Clinic vaccine
The vaccine behind many headlines was developed at Cleveland Clinic and targets alpha-lactalbumin, a protein that breast tissue makes during breastfeeding but that disappears afterward, while remaining present in most triple negative breast cancers. The idea is to teach the immune system to attack any cell that makes this "retired" protein. A phase 1 trial tested it in three groups: people who had finished treatment for early triple negative breast cancer and were at high risk of recurrence, cancer free people with BRCA1 or similar gene mutations who chose preventive mastectomy, and people with residual cancer after treatment. Final results, presented in December 2025, showed the vaccine was safe and well tolerated at the dose selected and produced the intended immune response in 74 percent of participants. That is an encouraging first step, but phase 1 trials are designed to test safety and immune response, not whether a vaccine prevents cancer. A larger phase 2 study, planned to open in late 2026, will begin to answer that.
Other breast cancer vaccines in trials
The Cleveland Clinic vaccine is one of many. Current US studies are testing vaccines that target HER2 for HER2 positive breast cancer, vaccines given alongside chemotherapy or immunotherapy for triple negative breast cancer, personalized vaccines built from the mutations in a person's own tumor, newer RNA based vaccines, and vaccines designed to stop DCIS from progressing to invasive cancer. In total, around 19 breast cancer vaccine studies are recruiting in the US right now, at different phases and for different groups of people. More vaccine research is on our vaccine clinical trials page.
Why triple negative breast cancer is a focus
Triple negative breast cancer lacks the three receptors that many treatments target, so hormone therapy and HER2 drugs do not work against it. It is more common in younger women, in Black women, and in people with BRCA1 mutations, and it is more likely to recur in the first years after treatment. That combination, few targeted options and a high risk window after treatment, makes it a natural focus for vaccines that aim to prevent recurrence. Our triple negative breast cancer clinical trials page lists studies recruiting now.
Who breast cancer vaccine trials are looking for
Because vaccines are being tested in several settings, eligibility varies widely. Many studies enroll people who have finished treatment for early stage breast cancer and are at high risk of it coming back, especially triple negative or HER2 positive disease. Some enroll people currently being treated, combining the vaccine with chemotherapy or immunotherapy, and some are for metastatic disease. Prevention studies may enroll people with a high risk gene, and a few enroll women with DCIS. Most require good overall health and specific results from your pathology report. In early studies everyone usually receives the vaccine, while in randomized studies you might receive the vaccine or a comparison; either way, the trial measures safety and immune response closely.
Our guide explains how placebo controlled trials work.
How to find a breast cancer vaccine study
AllClinicalTrials.com lists breast cancer studies recruiting across the US and Canada, including vaccine trials, and you can filter by location and phase; see our breast cancer clinical trials page. The application takes about 5 minutes: you answer questions about your diagnosis, treatments, and test results, and if a study near you looks like a match, the research team contacts you. Nothing is decided until you have gone through informed consent, and participation is voluntary at every step.
Three things to have ready: your breast cancer type (for example triple negative, HER2 positive, or hormone receptor positive) and stage, the treatments you have finished and when, and any genetic test results such as BRCA1 or BRCA2.
Common questions
Is there a vaccine for breast cancer? Not an approved one. Several vaccines are in clinical trials, and taking part in a study is currently the only way to receive one.
What were the Cleveland Clinic vaccine results? In the phase 1 trial, presented in December 2025, the vaccine was safe and well tolerated and produced the intended immune response in 74 percent of participants. Whether it prevents cancer will be tested in a phase 2 study planned for late 2026.
Who could the Cleveland Clinic vaccine help? It targets triple negative breast cancer, so the first people likely to benefit, if it works, are those at high risk of this type, such as people who have finished treatment for it or who carry BRCA1 mutations.
Can a vaccine prevent breast cancer from coming back? That is exactly what several trials are testing. Results so far show safety and immune responses, but proof that a vaccine prevents recurrence will take larger trials.
Is the breast cancer vaccine like the HPV vaccine? No. The HPV vaccine prevents a virus that causes some cancers. Breast cancer is not caused by a virus, so breast cancer vaccines target proteins on the cancer cells instead.
Can I join a vaccine trial if I have metastatic breast cancer? Some vaccine trials enroll people with metastatic disease, usually alongside other treatment. Others are only for people who have finished treatment for early stage cancer.
Are breast cancer vaccine trials safe? Every trial is reviewed by regulators and an ethics board, and safety is monitored closely. The risks are explained in the consent form before you decide.
Do breast cancer trial participants get paid? Some studies offer compensation for time and travel, and study related care is typically provided at no cost to participants. Compensation varies by trial and is always described during the informed consent process before you agree to anything.
See breast cancer clinical trials recruiting now
Browse open studies, filter by location, and apply in about 5 minutes: Breast Cancer Clinical Trials.