Researchers at the University of Wisconsin School of Medicine and Public Health are exploring the ideal vaccine booster strategy for immunosuppressed patients to protect those at higher risk of severe illness and complications from COVID-19 infection.

The goal of the clinical trial titled Additional Recombinant COVID-19 Humoral and Cell-Mediated Immunogenicity in Immunosuppressed Populations, or ARMOR, is to determine whether a recombinant booster COVID-19 vaccine dose will improve sustained immunity against the virus that causes COVID-19 in people who live with inflammatory bowel disease, also called IBD, or solid organ transplant recipients and whose medical treatments involve staying on immunosuppressive drugs.

Participants who enroll in this trial will receive the Novavax COVID-19 vaccine, which is a recombinant vaccine and differs from the Pfizer or Moderna drugs in that it directs the immune system to recognize specific pieces of the virus.

Solid organ transplant recipients take medications to suppress the immune system in order to prevent acute organ rejection. Similarly, patients with IBD are often prescribed immunosuppressant drugs to treat and manage their conditions.

Studies have shown that those who receive immunosuppressive medications, like corticosteroids, are at a higher risk for severe COVID-19 if they are infected, according to Freddy Caldera, DO, MS, associate professor of medicine at the UW School of Medicine and Public Health and gastroenterologist, UW Health.

Freddy Caldera
Freddy Caldera

“The COVID-19 virus is here to stay,” he said. “As we learn more about COVID-19, our research must also evolve to protect patients who are more vulnerable to getting the disease and experiencing long-term complications.” 

A recent report from the Centers for Disease Control and Prevention indicates that one in five Americans infected with COVID-19 endure long-term complications including blood clots, neurological issues and kidney issues. The significant health risks faced by immunosuppressed patients demands further research to develop more effective vaccine strategies, according to Caldera.

“There is a breadth of research on what happens immediately after infection however, we are still learning about the repercussions of getting COVID-19 and post-COVID complications,” he said. “As immunosuppressed populations return to more daily living, we must examine the best vaccine strategy to protect them from COVID-19, so they won’t have to trade feeling well with protection from this virus.”

The Novavax COVID-19 vaccine is one of the three that are recommended for the general population. This vaccine was updated in fall 2023 to include the spike protein from the Omicron variant lineage XBB. Researchers hypothesize that this type of vaccine, a recombinant vaccine, may prompt a more robust immune response than messenger RNA (mRNA) vaccines, like the Pfizer vaccine, according to Caldera.

“With each new vaccine that is developed, we have the potential to deliver greater protection,” he said. “If we discover recombinant vaccines can induce a robust immune response protection for an entire respiratory virus season with a single dose, this would make them a better alternative to mRNA vaccines.”

The trial takes place at University Hospital in Madison. Participants will receive the Novavax vaccine and have their blood drawn three times, once prior to vaccination, once 30 days after vaccination and once six months after vaccination. Researchers will assess immune system response after vaccination by evaluating levels of antibodies and T-cells. The cost of the vaccination is covered by the trial.

The study is run by the UW Clinical Trials Institute and funded by Novavax.

If you are interested in participating in the study and have IBD, email or call (608) 262-5405. If you have had a solid organ transplant, please email or call (608) 263-3439.