Stanford Medicine begins enrolling for COVID-19 vaccine trial

Stanford plans to enroll about 1,000 people as part of a large Phase 3 trial to determine whether a vaccine can protect against infection with the coronavirus.

- By Krista Conger

Clinical trial participant Walter Sobba and nursing manager Rich Brotherton.
Steve Fisch

Stanford Medicine has joined a large, Phase 3 clinical trial of an experimental vaccine against COVID-19.

The trial will test whether the vaccine, which is produced by the Janssen Pharmaceutical Companies of Johnson & Johnson, protects people from the disease. It will enroll some 60,000 people at about 180 sites around the world. The Stanford site is expected to enroll about 1,000 participants.  

Participants will receive either the vaccine or a placebo, and their health and immune responses will be monitored for about one year after their initial visits. If any participants become ill with symptoms of COVID-19, a health care provider will go to their homes to assess their health and collect a nasal sample to test for the presence of the novel coronavirus. If they are infected, Stanford physicians will monitor their disease progression. 

“We’re enrolling a wide variety of participants, but we are particularly interested in those who feel like their home or workplace exposure puts them at risk,” said Philip Grant, MD, assistant professor of medicine and the trial’s principal investigator at Stanford. “Teachers, grocery store workers, people who live in multigenerational households, health care workers and students on campus would all be good candidates for participation.”

Participants will be followed for two years and one month. They are expected to visit the trial site eight times: six in the first year and two in the second year. The initial visit will last about two hours; subsequent visits will consist of a short blood draw and symptom screening. If a participant develops COVID-19 during the study period, additional visits may be required.

Philip Grant

The Janssen vaccine uses the shell of a virus called an adenovirus, but the adenovirus genes have been replaced with genetic material that serves as a blueprint for the spike protein of the SARS-CoV2 coronavirus. After injection, the modified adenovirus delivers the blueprint for the spike protein into the cells of trial participants. The cells generate the protein, which alerts the immune system to prepare to fight off infection by the coronavirus. A similar technique has been used for vaccines against other diseases, including Ebola.

“This modified virus can’t replicate inside the body after injection, but it produces a strong immune response to the spike protein, similar to that seen in people who have recovered from an infection with SARS-CoV-2,” Grant said. “Our hope is that the immune response will provide durable protection against subsequent infection with COVID-19.”

Initial Phase 1 and 2 trials of the Janssen vaccine uncovered no major side effects or safety concerns when used in humans, and animal studies suggested that, unlike other vaccine candidates, one dose of the Janssen vaccine was sufficient to trigger a potentially protective immune response.

For information about enrolling,

About Stanford Medicine

Stanford Medicine is an integrated academic health system comprising the Stanford School of Medicine and adult and pediatric health care delivery systems. Together, they harness the full potential of biomedicine through collaborative research, education and clinical care for patients. For more information, please visit

2023 ISSUE 3

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