Clinical Edge

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Valacyclovir safely cut vertical CMV transmission

Key clinical point: Daily treatment with 8 g of valacyclovir safely cut maternal-fetal transmission of cytomegaliovirus.

Major finding: CMV transmission occurred in 11% of pregnancies treated with valacyclovir and in 30% of those treated with placebo.

Study details: A single-center, Israeli study that randomized 92 women with a primary CMV infection just before conception or during the first trimester.

Disclosures: The study received no commercial funding. Dr. Shahar-Nissan had no relevant disclosures.


ID Week 2019


This small Israeli study is very important. The powerful finding of the study was buttressed by its placebo-controlled design and by its follow-up. The findings need replication in a larger study, but despite the small size of the current study the findings are noteworthy because of the desperate need for a safe and effective intervention to reduce the risk for maternal-fetal transmission of cytomegalovirus (CMV) when a woman has a first infection just before conception or early during pregnancy. Several years ago, the Institute of Medicine made prevention of prenatal CMV transmission (by vaccination) a major health priority based on the high estimated burden of congenital CMV infection, Addressing this still unmet need remains an important goal given the substantial disability that congenital CMV causes for thousands of infants born each year.

Janet A. Englund, MD, is a professor of pediatric infectious diseases at the University of Washington in Seattle and at Seattle Children’s Hospital. She had no relevant disclosures. She made these comments in an interview.