A Surveillance Study of Susceptibility to Baloxavir Marboxil in Pediatric Participants With Influenza and Transmission of Influenza to Household Contacts
RO7771950 Versus Tucatinib in Combination With Trastuzumab and Capecitabine in People With Locally Advanced or Metastatic Breast Cancer That is Human Epidermal Growth Factor Receptor 2 (HER2)-Positive
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TMV Vaccine Therapy Alone and With Pembrolizumab for the Treatment of Recurrent and/or Metastatic Head and Neck Squamous Cell Cancer
BiCaZO: A Study Combining Two Immunotherapies (Cabozantinib and Nivolumab) to Treat Patients With Advanced Melanoma or Squamous Cell Head and Neck Cancer, an immunoMATCH Pilot Study
Testing the Addition of Anti-Cancer Drug, Cetuximab, to Standard of Care Treatment (Pembrolizumab) for Returning or Spreading Head and Neck Cancer After Previous Treatment
The Natural History of Severe Viral Infections and Characterization of Immune Defects in Patients Without Known Immunocompromise
Studying the PAGODA Algorithm for Chemotherapy Dose Changes to Prevent Unplanned Treatment Delays
First-in-Human Study of Mutant-selective PI3Kα Inhibitor, RLY-2608, as a Single Agent in Patients With Advanced Solid Tumors and in Combination With Endocrine Therapy +/- a CDK4/6 or CDK4 Inhibitor in Patients With Advanced Solid Tumors or Advanced Breast Cancer
A Study to Evaluate Efficacy, Safety, and Tolerability of Remibrutinib in Adult Participants With Severe Chronic Pruritus of Unknown Origin (CPUO)
A Study of a Selective ERBB2 Inhibitor (CGT4255), in Patients With Advanced Solid Tumors
What vaccine clinical trials are studying now
New flu vaccines. Moderna's mFlusiva, approved August 5, 2026 for adults 50 and older, is the first mRNA flu vaccine. In its Phase 3 trial it prevented about 27 percent more flu cases than a standard dose vaccine, with more short term side effects. Flu vaccine studies, including human challenge trials, are listed on our influenza clinical trials page.
Vaccines in pregnancy. Vaccinating a mother so antibodies pass to the baby is one of the most active areas of research. A Phase 3 trial of a group B streptococcus vaccine, a leading cause of serious infection in newborns, is recruiting pregnant participants at 120 US sites.
Pneumococcal and other bacterial vaccines. Next generation vaccines that cover more strains of the bacteria behind pneumonia and meningitis, tested against the vaccines in use today.
RSV vaccines. Combination and revaccination studies, covered on our RSV vaccine clinical trials page.
Cancer vaccines. These do not prevent cancer; they teach the immune system to attack a cancer that is already there. Intismeran, made for each patient from up to 34 mutations in their own tumor, met its main goal in a Phase 3 melanoma trial in August 2026 but is not yet approved. Smaller studies test vaccines for HER2 positive breast cancer, liver cancer, and HPV related cancers; see our melanoma and breast cancer pages.
COVID-19. Updated formulas are approved each season; the 2026 to 2027 mRNA formula is approved for adults 65 and older and for people 5 to 64 with a condition that raises their risk. Studies of COVID-19 and long COVID are on our COVID-19 page.
Human challenge studies. Healthy adults receive a vaccine or placebo, then a controlled dose of a virus such as influenza, in a monitored setting. They answer in weeks what field trials take seasons to show.
How vaccine trials differ from drug trials
Most vaccine trials enroll healthy people, not patients, so the safety bar is especially high and the studies are large: proving a vaccine prevents illness means waiting for enough people in the placebo group to get sick. That is why late stage vaccine trials often enroll tens of thousands of people, why they are usually placebo controlled or compared with an existing vaccine, and why they track side effects closely for days after each dose and safety for months. Our guide explains how long vaccine trials take, and our placebo controlled trials guide covers what the comparison group receives.
What is a human challenge trial?
A study in which healthy adults receive a vaccine or placebo and are then deliberately exposed to a controlled dose of a virus, such as influenza, while staying at a research unit under medical care. These studies are small, tightly regulated, and can show whether a vaccine works in weeks rather than seasons.
Who can participate in vaccine clinical trials?
Most preventive vaccine studies enroll healthy adults in a set age range, often 18 to 49 or 50 and older, without the infection in question and often without recent vaccination against it. Pregnancy vaccine studies enroll people in a specific window of pregnancy. Human challenge studies have the strictest rules, usually healthy adults 18 to 49 with no chronic conditions, and involve a stay at a research unit. Cancer vaccine studies, by contrast, enroll people with a specific cancer, often after surgery. Nearly all vaccine trials are randomized, so no one is promised the vaccine rather than the placebo or comparison vaccine. Eligibility always varies by study.
Considering volunteering in a clinical trial? Explore our comprehensive guide to learn more about why people choose to volunteer and the impact you can make in advancing medical research. Discover the process of volunteering, what to consider before applying and the potential benefits and risks involved.
Do vaccine trial participants get paid?
Some studies offer compensation for time and travel, and study related visits and tests are typically provided at no cost to participants. Human challenge studies, which involve a stay at a research unit, are described in more detail on our healthy volunteers page. Compensation varies by trial and is always described during the informed consent process before you agree to anything.
Curious whether clinical trials pay participants? Here's how compensation actually works.
How to enroll in a vaccine clinical trial
Enrolling in a clinical trial for vaccines through our platform is a straightforward and user-friendly process. Here's how to get started:
- Identify Your Trial: Use our search bar or filters to find clinical trials for vaccines that match your interests and needs. This first step simplifies the process of finding relevant research studies tailored to your needs.
- Select Your Preferred Location:To find trials conveniently located near you, simply input your preferred location into the dedicated filter bar on the left-hand side of the page.
- Explore Study Details: For in-depth information about each study, simply click the “Learn More” button. This will provide you with comprehensive details about the trial, including objectives, procedures, and eligibility criteria.
- Complete the Health Profile: After clicking on the “Get started” button you will be taken to our efficient 5-step application process to provide important health information. This helps us match you with the clinical trial that best fits your needs.
- Submit the Application: After completing the application, send it in. A clinical trial coordinator will review it and contact you regarding the possibility of participation.