Progress in Cytomegalovirus Vaccine Development

Cytomegalovirus (CMV) causes considerable morbidity and disability in infants who acquire the infection in utero. Despite potent antiviral therapies, CMV also continues to be a major cause of disease in immunocompromised patients. Vaccines for CMV, therefore, could provide protection against CMV disease in an array of high-risk patient populations. Although the correlates of vaccine-engendered immunity that limit CMV disease are not fully understood, there has been significant progress in elucidating some of the key immunological correlates of protection. The optimal CMV vaccine strategy may depend on the patient population being targeted for protection. This review provides an update on CMV vaccines that are currently in preclinical and clinical development, and outlines important, as yet unanswered, questions about the nature of protective immune responses that will be required of potential CMV immunization strategies. Such questions must be answered before an optimal vaccine, and vaccine use strategy, can be implemented in clinical practice.