It also will assess pausing immunosuppressive drugs for autoimmune disease to improve the antibody response to an additional Covid-19 shot.
Funded by the NIH unit National Institute of Allergy and Infectious Diseases (NIAID), the trial is being performed by the NIAID-funded Autoimmunity Centers of Excellence.
Initially, individuals with multiple sclerosis, pemphigus, rheumatoid arthritis, systemic lupus erythematosus or systemic sclerosis will be enrolled.
The immunosuppressive medication usually taken by these patient populations has been related to poor immune responses to vaccines, NIH noted.
A total of nearly 600 subjects aged 18 years or above will be enrolled at 15 to 20 sites across the US.
Before enrollment, subjects must have experienced a negative or suboptimal antibody response to two doses of the Covid-19 vaccine of Moderna or Pfizer-BioNTech, or one dose of the Johnson & Johnson Covid-19 vaccine.