Self-Amplifying mRNA COVID-19 Vaccine (LUNAR-COV19) Versus Comirnaty Vaccine in Adult Hematopoietic Cell Transplant Patients

This phase IIb trial compares the effect of LUNAR-COV19 vaccine to Comirnaty vaccine in treating adult patients who have received a hematopoietic cell transplant (HCT). Guidelines recommend repeating severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) vaccination of 3 messenger ribonucleic acid (mRNA) vaccines followed by a fourth booster 3-6 months after treatment. However, vaccination is less effective in HCT patients compared to healthy people due to impaired immune responses. LUNAR-COV19, a self-amplifying mRNA vaccine, may help the body's own immune system recognize the SARS-CoV-2 spike protein and fight the virus by using a special mRNA that copies itself for a stronger response. Vaccines made from mRNA with SARS-CoV-2, such as Comirnaty, may help the body build an effective immune response. This may provide active protection against SARS-CoV-2 infection. LUNAR-COV19 may be safe and tolerable and may generate a better and more durable immune response than the Comirnaty vaccine in adult patients who have received a HCT.