COVID-19 Trials / Trials in California
35 Recruiting Trials

Clinical Trials
for COVID-19 in California

35 clinical trials for COVID-19 are currently recruiting participants at study sites in California. Study-related care is provided at no cost.

35
Recruiting trials
79
Study sites
38
Cities
17
Industry-sponsored
6
Phase 2
8
Phase 3

COVID-19 clinical trials in California: what to expect

COVID-19 research has shifted from the acute illness to its aftermath and its prevention. The most active area is long COVID: trials of antivirals, immune treatments and rehabilitation for fatigue, brain fog, breathlessness and rapid-heartbeat symptoms that persist months after infection. Vaccine trials test updated and next-generation vaccines, including nasal and combined flu-and-COVID shots. Treatment trials for people at high risk, and prevention studies for people with weakened immune systems, continue as well.

In California, recruiting covid-19 studies are concentrated in Los Angeles, San Francisco, San Diego and La Jolla, with sites in 34 other cities. 17 of the 35 are run by a drug or device company, which usually means a larger study with travel reimbursement; the rest are academic or hospital-led.

Who COVID-19 trials usually look for

Long COVID trials ask for symptoms that began after a confirmed or strongly suspected infection and have lasted at least three months, often with a particular symptom named. Acute treatment trials need a positive test within the past few days plus a risk factor such as age or a chronic condition. Vaccine trials specify an age group and your vaccination history, and most want people who are generally healthy. Many trials exclude pregnancy and a recent infection or vaccination.

What taking part involves

Long COVID trials run twelve to twenty-four weeks with questionnaires, sometimes exercise or breathing tests, and visits that can often be done by phone or video; many are placebo controlled. Vaccine trials involve one or two injections, a symptom diary for a week after each, a few blood draws and follow-up calls for a year or more. Acute treatment trials start the day you enroll, with swabs and check-ins for a few weeks. Study treatment and tests are free and visits are usually paid.

Questions worth asking the study team

How many visits must be in person; the chance of placebo; whether you can continue your current treatments; what counts as documentation of your original infection; and whether you will learn your own test results.

Showing 20 of 35 recruiting COVID-19 trials in California

A Clinical Study of Molnupiravir to Prevent Severe Illness From Coronavirus Disease 2019 (COVID-19) in People Who Are High Risk (MK-4482-023)
PHASE3 Castroville, California +4 sites NCT06667700
This trial is looking for adults at high risk for severe illness from COVID-19. Participants will take the study drug molnupiravir or a placebo and monitor their health over time.
Recruiting
A Study to Learn About a Study Medicine Called Ibuzatrelvir in Adult and Adolescent Patients With COVID-19 Who Are Not Hospitalized But Are at Risk For Severe Disease
PHASE3 Bakersfield, California +4 sites NCT06679140
This trial is looking for teens aged 12 to 17 who weigh at least 40 kg and adults aged 18 and older, especially those at risk of getting seriously ill from COVID-19. Participants should have recently tested positive for COVID-19 and show some symptoms, but they shouldn’t be in need of hospitalization. People with certain serious health issues or those who are very sick right now won't be able to join.
Recruiting
A Study to Learn About the Study Medicine Ibuzatrelvir in Adults With COVID-19 Who Are Severely Immunocompromised
PHASE3 Canoga Park, California +4 sites NCT07013474
This trial is looking for adults who are severely immunocompromised and have COVID-19. Participants will receive either ibuzatrelvir alone or with another medication to see how well it works against the virus.
Recruiting
EPIC-Peds: A Study to Learn About the Study Medicine Called PF-07321332 (Nirmatrelvir)/Ritonavir in Patients Under 18 Years of Age With COVID-19 That Are Not Hospitalized But Are at Risk for Severe Disease
PHASE3 Los Angeles, California +4 sites NCT05261139
This trial is looking for young patients under 18 years old who have COVID-19 but are not hospitalized, and may be at risk for more severe illness. Participants will be given a medicine called nirmatrelvir/ritonavir to help treat their condition.
Recruiting
Study of a Recombinant Spike COVID-19 Vaccine With Matrix-M in Older Adults and People at Increased Risk of Severe COVID-19
PHASE4 Fair Oaks, California +4 sites NCT07861542
This trial is looking for older adults and younger individuals with health conditions that increase their risk of severe COVID-19. Participants will receive a single injection and have follow-up calls over three months.
Recruiting
A Study on the Safety and Immune Response of Investigational mRNA Seasonal Flu/COVID-19 Combination Vaccine in Adults
PHASE1 Fair Oaks, California +4 sites NCT07464314
This trial is looking for healthy adults aged 65 to 85 years who want to help test a new vaccine that combines protection against the flu and COVID-19. Participants will receive different doses of the vaccine or standard vaccines and will be monitored for side effects and immune response.
Recruiting
A Study to Learn About a COVID-19 Vaccine in Healthy Adults 18 Through 64 Years of Age
PHASE4 Walnut Creek, California +4 sites NCT07730450
This trial is looking for healthy adults aged 18 to 64 years to study the safety and effects of an updated COVID-19 vaccine. Participants will receive one injection and be in the study for about 12 months.
Recruiting
Multiparametric [18F]F-AraG Imaging in Post-Acute Sequelae of COVID-19 (PASC)
EARLY_PHASE1 Sacramento, California +1 sites NCT07076862
This trial is looking for adults who have experienced symptoms after recovering from COVID-19. Participants will undergo special imaging and provide information about their health to help researchers understand Long COVID better.
Recruiting
A Phase 1/2A, Randomized Study of a T Follicular Helper (TFH)-Targeting Genetic Vaccine Strategy Designed to Induce Broad, Durable Immune Responses
PHASE1 Los Angeles, California +1 sites NCT06810934
This trial is looking for healthy adults aged 40 to 64 to test two new COVID-19 booster vaccines. Participants will receive one dose of either vaccine or a placebo and will be monitored for side effects, with samples taken to measure immune response.
Recruiting
Pharmacokinetics, Pharmacodynamics, and Safety Profile of Understudied Drugs Administered to Children Per Standard of Care (POPS)
N/A Los Angeles, California +4 sites NCT04278404
This trial is looking for children and young adults who are 21 years old or younger and are currently taking certain medications, or who have had a recent COVID-19 infection. They cannot be pregnant or have had certain recent medical procedures like dialysis, organ transplants, or other serious treatments. If you think your child might fit this description, it could be worth considering.
Recruiting
Effect of Messaging on Pragmatic Outcomes Within an Integrated Healthcare System
NA Pasadena, California NCT07838038
This trial is looking for adults who are at high risk for severe COVID-19 illness. Participants will receive messages and reminders about COVID-19 vaccine options to see if it helps them get vaccinated.
Recruiting
Phase III DAS181 Lower Tract PIV Infection in Immunocompromised Subjects (Substudy: DAS181 for COVID-19): RCT Study
PHASE3 Duarte, California +4 sites NCT03808922
This trial is looking for immunocompromised patients who have a lower respiratory tract infection due to parainfluenza. Participants will receive treatment with DAS181 and need to meet specific health criteria.
Recruiting
Imaging Immune Activation in COVID-19
PHASE2 San Francisco, California NCT04815096
This trial is looking for people who have recently recovered from COVID-19 to participate in an imaging study. Participants will receive a small dose of a tracer followed by a full-body scan to study immune activity.
Recruiting
Long-term Impact of Infection With Novel Coronavirus (COVID-19)
N/A San Francisco, California NCT04362150
This trial is looking for volunteers who have recovered from COVID-19. Participants will provide samples to help researchers learn about the immune response after infection.
Recruiting
Impact of the Coronavirus (COVID-19) on Patients With Cancer
N/A Stanford, California NCT04330521
This trial is looking for adult patients with cancer to complete a survey about how COVID-19 affects them. Participants will be sharing their experiences and perspectives.
Recruiting
COVID-19 International Drug Pregnancy Registry
N/A Los Angeles, California NCT05013632
This trial is looking for pregnant women or those who were recently pregnant and have had COVID-19. Participants will help researchers understand how COVID-19 treatments affect pregnancy and newborns.
Recruiting
A Study to Explore the Role of Gut Flora in COVID-19 Infection
N/A Ventura, California NCT04359836
This trial is looking for adults who have COVID-19 and want to help understand if the virus can be found in their stool. Participants will need to agree to the study and meet certain health guidelines.
Recruiting
A Study to Examine Anktiva for the Treatment of COVID-19.
PHASE2 El Segundo, California NCT07123727
This trial is looking for adults who have been experiencing ongoing symptoms after recovering from COVID-19. Participants will take the medication Anktiva to see if it helps treat those lingering symptoms.
Recruiting
Phase 2a Multiple Ascending Dose Study in Hospitalized Patients With Pneumonia.
PHASE2 Newport Beach, California +4 sites NCT05123755
This trial is looking for patients in the hospital with pneumonia who need extra oxygen. If you join, you will receive either the AV-001 Injection or a placebo each day until you leave the hospital or for up to 28 days.
Recruiting
A Study to Assess Anktiva in Patients With Long Covid-19.
PHASE2 San Francisco, California NCT07108036
Recruiting
See all 35 COVID-19 trials in California

Where the COVID-19 studies are in California

Research sites running the most studies
  • University of California San Francisco, San Francisco2 trials
  • 310 Clinical Research, Inglewood1 trial
  • Acclaim Clinical Research, San Diego1 trial
  • Altasciences, Cypress1 trial
  • Amicis Research Center - Granada Hills, Granada Hills1 trial
  • Ascada Health PC dba Ascada Research ( Site 3750), Fullerton1 trial
By city

Counts are recruiting studies listing at least one site in California, from ClinicalTrials.gov, refreshed every two days.

COVID-19 clinical trials in California: common questions

How many COVID-19 clinical trials are recruiting in California?
TrialFinder currently lists 35 recruiting COVID-19 clinical trials with study sites in California. Results are updated regularly from ClinicalTrials.gov, the official U.S. registry of clinical studies.
Where are COVID-19 clinical trials located in California?
Study sites for the COVID-19 trials listed on this page include Castroville, Bakersfield, Canoga Park, Los Angeles, Fair Oaks, Walnut Creek. Each trial page lists every participating site with contact details, so you can find the location closest to you.
Do I need insurance to join a COVID-19 clinical trial in California?
No. Study-related care is covered by the trial sponsor at no cost to participants, including the study treatment, required lab tests and study visits. Many COVID-19 trials in California also compensate participants for time and travel. Health insurance is not required to search or enroll.
How do I qualify for a COVID-19 clinical trial in California?
Each study sets its own criteria based on age, COVID-19 diagnosis details, prior treatments, current medications and general health. The fastest way to find out is to contact a research site directly — most will pre-screen you by phone in 10 to 15 minutes at no charge. You can also create a free TrialFinder profile to be matched automatically.
Are there clinical trials for long COVID?
Yes, and they are among the most active COVID trials. Most require symptoms that have lasted three months or more after an infection and name the symptom they study, such as fatigue, brain fog or breathlessness.
Can I join a COVID vaccine trial if I am already vaccinated?
Usually yes. Most current vaccine trials test updated or next-generation vaccines in people who have been vaccinated before, and ask about the date of your last dose.
Do I need a positive test to join a COVID treatment trial?
For acute treatment, yes, within the last few days. Long COVID trials accept a past positive test or a documented clinical diagnosis, and some accept a strongly suspected infection.
COVID-19 Trials in Other States
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Helpful Reading
Are Clinical Trials Safe? What Patients Should Know
How clinical trial safety works — phases, IRB oversight, informed consent, and your right to withdraw — plus the real risks and questions to ask.
How to Know If You Qualify for a Clinical Trial
Every trial has eligibility criteria based on diagnosis, age, and medical history. Here's how to tell if you qualify — and what to do if you're not sure.
Clinical Trials Without Insurance: What You Need to Know
Clinical trials cover the cost of study-related care, making them one of the few ways to access treatment without health insurance. Here's what's covered.
All guides →

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About COVID-19 Trials

COVID-19 trials study antiviral agents, monoclonal antibodies, long-COVID interventions, and vaccine platforms for prevention and treatment of SARS-CoV-2 infection.

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