Infants with congenital HHV-6 infection have lower Bayley scores at 12 months
Investigators at the University of Rochester have reported that 57 children born with HHV-6 congenital infection had slightly lower scores on the Bayley Scale of Infant Development at 12 months than matched control children who did not have congenital infection. In the US, approximately 1% of infants have congenital HHV-6. Of those, 86% of them have inherited ciHHV-6 passed through the germ line, and 14% are infected transplacentally from their ciHHV-6 mothers (Gravel 2013).
Drs. Mary T. Caserta (L) & Caroline B. Hall (R)
Pediatric infectious disease specialist Mary T. Caserta (left) completed this study that was begun by her associate, the late Caroline B. Hall (right) to determine the impact of HHV-6 congenital infection. Infants exposed to the closely related cytomegalovirus (HHV-5) have an increased risk of neurodevelopment complications and sensory deficits, and they are routinely treated with ganciclovir when symptomatic at birth. Unfortunately, CMV congenital infections are not always symptomatic at birth and can reactivate in brain and nervous tissues after lying dormant for years. Some researchers have similar concerns regarding HHV-6.
Caserta and Hall identified 34 infants with inherited ciHHV-6 and 5 non-ciHHV-6 infants infected as fetuses by active virus from their mothers with ciHHV-6. While the ciHHV-6 infants scored more than 4 points lower than controls on the Bayley Mental Development Index, no difference was found on either the Fagan test of novelty preference or the Visual Expectation test that measures reaction time and anticipatory behavior. There was no difference in Bayley scores between controls and the 5 infants with transplacentally acquired HHV-6, but the authors caution that the number of infants studied was too small for any conclusions to be drawn at this time.
Because it has now been demonstrated that inherited HHV-6 can activate and produce infectious virions (Endo 2014), new concerns have been raised about active HHV-6 virus in individuals with immune deficiencies and for ciHHV-6 individuals exposed to specific drugs such as HDAC inhibitors and high dose steroids, which have been shown to activate integrated virus in vitro (Arbuckle 2010).
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