Definition

A messenger RNA (mRNA) vaccine consisting of six mRNAs five of which encode the human cytomegalovirus (CMV) subunits that form the membrane-bound pentamer protein complex and one that encodes the full-length membrane-bound glycoprotein B (gB), with potential immunostimulatory activity against CMV. Upon intramuscular (IM) administration of the CMV pentamer complex proteins/gB-encoding mRNA vaccine mRNA-1647, the mRNAs are translated by the cellular protein translation machinery to produce the proteins. This exposes the immune system to the six peptides, activates both humoral and cellular immune responses, and may provide active immunization against both the pentamer proteins and gB and therefore against CMV infection. Both the pentamer, consisting of gH, gL, UL128, UL130 and UL131 proteins, and gB are essential for CMV to infect barrier epithelial surfaces. CMV can cause significant disease in immunocompromised patients.