Currently, no vaccine is licensed to prevent infection with cytomegalovirus (CMV). Given the devastation caused by this virus, a safe and effective vaccine would be of tremendous value.
CMV is a ubiquitous infection that is usually asymptomatic in otherwise healthy people; about 10 percent, however, will develop a mononucleosis-like syndrome.
CMV infections of the unborn child, on the other hand, are not benign. A recent meta-analysis of published studies showed that 0.64 percent of pregnancies are complicated by CMV infection. This corresponds to about 60,000 affected infants in the United States and Europe. Congenital CMV infections can cause deafness, microcephaly, severe developmental disabilities, seizure disorders and cerebral palsy. Hope for a vaccine resides in the finding that unborn babies are protected against the disease if their mothers are naturally immune prior to delivery.
CMV is also an important problem for children and adults who are immune compromised, such as those receiving chemotherapy for cancer. In this group, CMV causes hepatitis, pneumonitis, retinitis and enteritis.
Recently, Dai Wang and coworkers took a strain of CMV (AD169) and modified it so that it was replication defective yet highly immunogenic (Wang D, Freed DC, He X, et al. A replication-defective human cytomegalovirus vaccine for prevention of congenital infection, Sci Transl Med. 2016 Oct 26;8:(362):326ra145). They found that the vaccine was immunogenic in a variety of animal species, including nonhuman primates, and induced excellent antibody as well as T-cell responses. These findings provide a great deal of hope for a future vaccine.