At ESCMID Global 2025, one of the world’s leading forums for infectious disease and clinical microbiology, congenital cytomegalovirus (CMV) took center stage as experts explored new avenues in screening, prevention, and management. CMV remains the most common congenital infection worldwide, yet it is still underdiagnosed and under-addressed in many healthcare systems. With consequences that range from hearing loss to neurodevelopmental disorders, timely identification and effective prevention strategies are crucial.Dr. Marianne Leruez-Ville, a prominent clinical virologist, shared her insights into improving diagnostic tools, the promise of vaccines and antivirals, and how a multidisciplinary approach is key to optimizing outcomes for both mothers and infants.
Marianne Leruez-Ville, MD
Université Paris Cité, URP 7328 FETUS, Paris, France
Marianne Leruez-Ville is a MD specialized in Clinical Virology and holds a PHD in Virology. She is a consultant in clinical Virology and at the head of the Microbiology laboratory of Necker-Hospital for sick children in Paris, France. She is the director of the congenital CMV laboratory within the French National Reference Center for Herpes Viruses and she belongs to a research group focusing on fetal abnormalities and their treatment (EA 7328, Imagine Institute, University Paris Cité). Her main research interest is clinical virology in relation to congenital CMV infection and she has made significant contributions in the study on the pre and postnatal diagnosis, management and treatment of this infection. She is a founder member and actual treasurer of the “European Congenital CMV Initiative (ECCI)”, European association founded to promote excellence in the management of congenital CMV infection.
IDF: How can we optimize prenatal screening methods for congenital CMV, such as serological testing and PCR, to improve diagnostic accuracy and early identification rates, especially in reducing false-positive and false-negative results?
Dr. Marianne Leruez-Ville: That’s a very important and quite complex question. We already have serological tests with relatively high sensitivity for detecting primary CMV infection during pregnancy, particularly IgM tests. These help us identify women who may have acquired the infection in the first trimester. However, different assays vary in sensitivity, so it’s essential to select the most reliable ones in the lab.
Once both IgM and IgG are positive, the next step is the IgG avidity test, which helps determine whether the infection is recent. There are currently three high-throughput, fully automated tests widely used in Europe, and they’re fairly effective at identifying recent infections. However, the challenge lies in specificity: a low avidity result may persist well beyond the initial infection, potentially leading to overdiagnosis.
Regarding PCR, testing blood or urine samples is not particularly helpful for diagnosing primary infections during pregnancy. That’s why we continue to rely on classical serology—IgG, IgM, and avidity—as the diagnostic cornerstone. There is certainly room for improvement, especially in minimizing false positives and negatives, but for now, this combination remains the standard.
IDF: What are your thoughts on the application potential of new preventive strategies for congenital CMV, such as vaccines and antiviral drugs? How can we balance the benefits and risks of these measures, particularly in high-risk pregnant populations?
Dr. Marianne Leruez-Ville: That’s a great question, thank you. A vaccine would be the most effective long-term strategy. Ideally, it could be administered to seronegative women of childbearing age or even in childhood, similar to how rubella vaccination is handled. Vaccinating children could prevent transmission within families and reduce the overall burden of CMV in pregnancy. However, we still need a vaccine that is both long-lasting and highly effective—something we don’t yet have.
Until such a vaccine becomes available, our focus is on preventing vertical transmission. In Europe, we currently use high-dose valacyclovir (8 grams per day) in women with primary CMV infection during the first trimester. This therapy has been shown to reduce transmission by about 70%, which is significant but not complete.
Unfortunately, valacyclovir is not the most effective antiviral against CMV—it’s better suited for herpes simplex or varicella. Valganciclovir would be ideal, but it cannot be used during pregnancy due to its teratogenic potential. Newer antivirals like letermovir and maribavir, currently approved for immunocompromised patients, offer hope. However, we lack the safety data needed to consider their use in pregnant populations. Clinical trials in this area are urgently needed.
IDF: How can we better integrate multidisciplinary resources and expertise in the management of congenital CMV? What specific challenges do you think need to be addressed in the implementation of these consensus guidelines?
Dr. Marianne Leruez-Ville: Managing congenital CMV is undoubtedly a multidisciplinary effort. As a clinical virologist, I work closely with obstetricians, midwives, and pediatric infectious disease specialists. Each week, we hold dedicated meetings to review cases of women with confirmed primary CMV infection during pregnancy. Together, we discuss and define the most appropriate strategy tailored to each patient’s specific situation.
This collaboration allows for a coordinated approach to diagnosis, treatment, and counseling. However, one of the biggest challenges is ensuring consistent adherence to consensus guidelines, particularly as new research continues to evolve. It also requires strong communication channels and institutional support to maintain these collaborations across departments. But when it’s done well, the results can significantly improve outcomes for both mother and child.
As underscored by Dr. Marianne Leruez-Ville, tackling congenital CMV effectively requires a combination of accurate diagnostics, evidence-based preventive strategies, and close collaboration among clinical teams. While the current tools provide a solid foundation, there is a clear need for improved testing technologies, safer and more effective antiviral treatments, and—most critically—a viable vaccine.
Until such advancements become available, multidisciplinary teamwork and proactive screening remain our most powerful tools to reduce the burden of this often-overlooked infection. The insights shared at ESCMID Global 2025 represent a promising step toward a more integrated and preventive approach to congenital CMV care.
