NEW YORK (Reuters Health) - An important cause of neurological impairment
in infants -- infection with cytomegalovirus while they are in the womb -- may
be curbed with the use of a new vaccine.
Most adults have been infected with cytomegalovirus or CMV, usually with
negligible consequences. However, when women become infected with CMV for the
first time while they are pregnant, there is a danger that their baby will also
be infected. In some cases, this "congenital" CMV infection can lead to
permanent defects such as hearing loss, vision loss, mental disability, lack of
coordination, or seizures.
Now, a study in this week's New England Journal of Medicine reports that a newly
developed CMV vaccine reduces cases of CMV infection in women and has the
potential to decrease congenital CMV infection.
"The development of a vaccine for the prevention of congenital CMV infection was
listed as a top priority for the US by a committee of the Institute of Medicine
in 2001," Dr. Robert F. Pass, from the University of Alabama, Birmingham, and
colleagues point out in the report.
Finding an effective CMV vaccine, however, has been a challenge. The first
trials of a CMV vaccine began over three decades ago. In the present trial, the
researchers tested a vaccine containing a protein found on the envelope of
cytomegalovirus and an adjuvant to increase the immune response.
A total of 464 non-pregnant, CMV-negative women, between 14 and 40 years of age,
were given three doses of the vaccine or an inactive "placebo" over a six-month
period.
During follow-up, 18 CMV infections were seen in the vaccine group compared with
31 in the placebo group. Further analysis confirmed that women given the vaccine
were significantly more likely to remain uninfected over a period of 42 months.
Ninety-seven women in the vaccine group and 118 in the placebo group became
pregnant after vaccination. One congenital CMV infection occurred among 81 live
births in the vaccine group, compared with 3 cases among 97 live births in the
placebo group.
Two editorialists comment that although side effects were more common with the
active vaccine, they were generally mild in nature, and further studies of the
vaccine are therefore acceptable.
SOURCE: New England Journal of Medicine, March 19, 2009.
