CMV Infection in HIV-Positive Women Increases Chance of Passing HIV to Infant

A new study out of the University of California in Los Angeles (UCLA) has provided evidence that shows that “HIV-positive women with cytomegalovirus (CMV) in their urine at the time of labor and delivery are more than 5 times likelier than HIV-positive women without CMV to transmit HIV to their infants.” In addition, the women are almost 30 times more likely to transmit CMV to their infants, according to the press release on the study.

A common virus, CMV infects individuals of all ages. According to the Centers for Disease Control and Prevention (CDC), approximately 1 in 3 children become infected with the virus before age 5 and over 50% of adults will have been infected with the virus by the time they reach 40. Once an individual becomes infected, the virus will remain in the body for life and much like chickenpox, can reactivate. In addition, “a person can also be reinfected with a different strain of the virus.”

Although most individuals will not show any symptoms from the infection, those with weakened immune systems and babies who become congenitally infected with the virus are at risk of serious health problems as a result of the infection. Babies who are born with congenital CMV “can have brain, liver, spleen, lung, and growth problems. Hearing loss is the most common health problems in babies born with congenital CMV infection, which may be detected soon after birth or may develop later in childhood.”

Experts are already aware of the risk of congenital CMV transmission; however, the UCLA study is the first to show a connection between the presence of virus in the pregnant woman’s urine, and transference of the virus to the infant. "The findings were surprising because prior studies in healthy pregnant women have not shown an association between CMV detection in urine, or even cervical secretions, and congenital CMV infection," stated senior study author Karen Nielsen, MD, a professor of clinical pediatrics in the division of infectious diseases at the David Geffen School of Medicine at UCLA in the press release.

For the study, “the researchers evaluated 260 pairs of [HIV-infected] mothers and their infants—222 from the Americas and 38 from South Africa—who were enrolled in the perinatal the National Institute of Child Health and Human Development HPTN 040 study (distinguished by no antiretroviral use before labor).” Urine specimens from the mothers and the infants, “were tested by qualitative real-time polymerase chain reaction (RT-PCR) for CMV DNA with quantitative RT-PCR performed on positive specimens.”

The results of the study showed that 9.2% of the women (24) “had detectable CMV viruria by qualitative PCR,” which was not associated with their mean CD4 counts or HIV viral load. Instead the researchers determined this was associated with a younger age of the mothers (P = .02).

A total of 3.8% of the infants had congenital CMV (10). Those women, “with detectable peripartum CMV viruria were more likely to have infants with congenital CMV than those without: 20.8% (5/24) versus 2.1% (5/236), (P = .0001). Women with CMV viruria had significantly higher rates of HIV perinatal transmission (29.2% vs. 8.1%, P = .002).”

The researchers found that other significant risk factors for congenital CMV included the mother having gonorrhea (aOR, 19.5; 95% CI, 2.5—151.3) and a higher HIV log10 viral load (OR, 2.8; 95% CI, 1.3–6.3).

The study was not without limitations. Firstly, “the sample size was determined by the availability of urine samples from the mothers.” Second, “women in the overall study from which data was drawn were diagnosed with HIV at the time of labor and delivery, [and] so results of the UCLA-led research are not applicable to pregnant women with HIV who are on antiretroviral treatment during pregnancy.”

Despite these limitations, Kristina Adachi, MD, postdoctoral researcher in pediatric infectious diseases in the UCLA department of pediatrics and the study's lead author argues that the results, “underscore the importance of controlling HIV-infection during pregnancy through use of antiretrovirals in the prevention of both CMV and HIV transmission from mothers to infants.”