Current prospects for immunization against cytomegaloviral disease

Cytomegaloviral (CMV) seronegative women who acquire a primary CMV infection during pregnancy are at the greatest risk for delivering infants who may be deaf or intellectually handicapped because of congenital CMV infection. Maternal immunization before pregnancy may protect newborns from congenital disease because mothers who are naturally seropositive are protected against secondary infection and because newborns who acquire CMV either via transfusion or transplacentally are protected if their mothers had antibodies to CMV prior to pregnancy. Further evidence for the feasibility of immunization for CMV comes from studies of patients immunocompromised following solid organ transplantation protection. These patients are protected against severe cytomegaloviral disease by immunity acquired either by wild-type infection prior to transplantation or by passive or active immunization. In three randomized placebo-controlled studies, live attenuated CMV Towne vaccine has successfully protected seronegative recipients of seropositive kidneys from severe CMV disease by inducing humoral and cellular immunity. Subunit vaccines comprised of glycoprotein gB, the viral component containing the majority of viral neutralizing epitopes, are in the early phases of study, as are studies with highly immunogenic preparations of Towne vaccine. Given all of these facts, safe and effective CMV immunoprophylaxis against CMV disease is possible.