Congenital cytomegalovirus: Public health action towards awareness, prevention, and treatment

Burden of Congenital CMV Infection: A Narrative Review and Implications for Public Health Interventions

Cytomegalovirus causes the most common congenital infection worldwide. With most infants asymptomatic at birth, the few affected may present with variable clinical scenarios, from isolated hearing loss to severe neurologic impairment. Public health interventions include all actions at the health system, community, and individual levels that aim at reducing the burden of congenital Cytomegalovirus. This review examines the literature on maternal and neonatal screening programs in light of current evidence for treatment and the development of vaccines against Cytomegalovirus. Potential biases and benefits of these interventions are outlined, with the objective of increasing awareness about the problem and providing readers with data and critical tools to participate in this ongoing debate.

Knowledge of cytomegalovirus and available prevention strategies in pregnancy: a cross-sectional study in Portugal

OBJECTIVE

Maternal and fetal congenital infection by cytomegalovirus (CMV) during pregnancy is the leading infectious cause of neurologic impairment and hearing loss. Efforts at limiting CMV exposure are based on hygienic measures. This study assessed the relationship between CMV knowledge and pregnant women's time perspective as per the Zimbardo Time Perspective Inventory (ZTPI) scale.

METHODS

We conducted a prospective descriptive study at a secondary-care Portuguese hospital between October to November 2021. All consecutive pregnant women in antenatal third-trimester appointments were included. The questionnaire included: sociodemographic data, knowledge about CMV, and the ZTPI scale, validated to our population. The number of correct answers in the knowledge section of the questionnaire was tallied to determine the individual knowledge score (KS). We investigated patients subjective perceptions of CMV infection during pregnancy, CMV knowledge, and CMV serologic status of pregnant women.

RESULTS

We enrolled 96 pregnant women. 81.0% had not previously heard about CMV and only 8.8% had heard about it through their obstetrician. No significant association between awareness of CMV and education level was detected. 16.0% of pregnant women declared that they were aware of the hygienic measures for CMV. The CMV serology was performed in 21.3% of those enrolled in the preconception assessment, and 13.8% proved to be immune. From the time perspective, half of the women displayed a future-oriented attitude. Future-oriented women had significantly higher KS. No significant association was found between KS and education level, age, or previous pregnancy. There was a significant association between KS and women that work in health care.

CONCLUSIONS

Most patients had no knowledge of CMV. Being a medical professional and having a future-oriented outlook increases knowledge about CMV. Primary health care and obstetrics doctors may play a crucial role in informing pregnant women of antenatal appointments. The CMV serology coverage is scarce in this sample. This study constitutes a first step toward raising the awareness of the general population about CMV.

Optimizing age specific strategies of vaccination for prevention of cytomegalovirus infection in the US using agent-based simulation

BACKGROUND

There is an urgent need to develop a cytomegalovirus (CMV) vaccine as it remains the leading cause of birth defects in the United States. While several CMV vaccine candidates are currently in late-stage clinical trials, the most effective vaccination program remains an open research question.

METHODS

To take into account the critical uncertainties when evaluating the vaccine impact on both vertical (congenital) and horizontal CMV transmissions, we developed a CMV agent-based model representative of the US population and contact network structures.

RESULTS

We evaluated 648 vaccination scenarios under various assumptions of vaccination age, vaccine efficacy, protection duration, and vaccination coverage. The optimal age of vaccination under all scenarios is shown to be during early childhood. However, a relatively modest benefit was also seen with vaccination of females of reproduction age (around age of 25) assuming near universal coverage and long vaccine-mediated protection.

CONCLUSIONS

This study highlights the important need for a pediatric vaccination program in mitigating CMV in the United States. Our model is poised to investigate further location-based vaccine effectiveness questions in future planning of both clinical trials as well as eventual program implementation.

Microelectromechanical system-based biosensor for label-free detection of human cytomegalovirus

The human cytomegalovirus (HCMV) is an asymptomatic common virus that is typically harmless, but in some cases, it can be life threatening. Thus, there is an urgent need to develop novel diagnostic methods and strengthen the efforts to combat this virus. A microcantilever-based biosensor functionalised with the UL83-antibody of HCMV (UL83-HCMV antibody) has been developed to detect the UL83-antigen of HCMV (UL83-HCMV antigen) at different concentrations ranging from 0.3 to 300 ng/ml. The response of the biosensor to the presence of UL83-HCMV antigen was measured through the shift in resonance frequency before and after antigen-antibody binding. The system shows a low detection limit of 84 pg/ml, which is comparable to traditional sensors, and a detection time of less than 15 min was achieved. The selectivity of the sensor was demonstrated using three different proteins with and without the UL83-HCMV antigen. The biosensor shows high selectivity for the UL83-HCMV antigen. Mass loading by the UL83-HCMV antigen was roughly estimated with a sensitivity of ∼30 fg/Hz. This technique is crucial for the fabrication of portable and low-cost biosensors that can be used in real-time monitoring and enables early medical diagnosis.

Seroprevalence of Epstein-Barr virus and cytomegalovirus infections in Presidente Figueiredo, Amazonas, Brazil

Epstein-Barr virus (EBV) and cytomegalovirus (CMV) infections affect around 95% of the world's population. In Brazil, there are few epidemiological reports related to EBV and CMV infection, especially in the western Amazon region. This study aimed to estimate the seroprevalence of EBV and CMV infection in individuals residents in Presidente Figueiredo, Amazonas, Brazil. Blood samples of 443 individuals were tested for the presence of anti-EBV and anti-CMV IgG antibodies through an enzyme-linked immunosorbent assay. EBV (95.9%; 95% CI: 0.94;0.98), CMV (96.8%; 95% CI: 0.95;0.98) and CMV/EBV (93%;95% CI: 0.91-0.95) coinfection were highly prevalent in the study population. Children (1 to 5 years) not attending school were less susceptible to EBV (OR 0.15; 95% CI: 0.05-0.52; p = 0.017) and CMV infections (OR 0.05; 95% CI: 0.02 - 0.17; p < 0.0001). Teenagers at high school showed increased susceptibility to CMV infection (OR 4.65; 95%CI: 1.43-15.08; p = .013) and EBV/CMV co-infection (OR 3.04; 95%CI: 1.44-6.45; p = 0.005). The seroprevalence of CMV and EBV infections were preeminent and tend to increase with age in the study population. Either attendance to a daycare facility or primary school before the age of 5 years may increase the susceptibility to EBV or CMV infection.

Profiling Human CMV-specific T cell responses reveals novel immunogenic ORFs

Despite the prevalence and medical significance of human cytomegalovirus (HCMV) infections, a systematic analysis of the targets of T cell recognition in humans that spans the entire genome and includes recently described potential novel ORFs is not available. Here, we screened a library of epitopes predicted to bind HLA class II that spans over 350 different HCMV ORFs and includes ∼150 previously described and ∼200 recently described potential novel ORFs using an ex vivo IFNγ fluorospot assay. We identified 235 unique HCMV specific epitopes derived from 100 ORFs, some previously described as immunodominant and others that were not previously described to be immunogenic. Of those, 41 belong to the set of recently reported novel ORFs, thus providing evidence that at least some of these are actually expressed in vivo in humans. These data reveal that the breadth of the human T cell response to HCMV is much greater than previously thought. The ORFs and epitopes identified will help elucidate how T cell immunity relates to HCMV pathogenesis and instruct ongoing HCMV vaccine research. Importance To understand the crucial role of adaptive immunity in controlling cytomegalovirus infection and disease, we systematically analyzed the CMV 'ORFeome' to identify new CMV epitopes targeted primarily by CD4 T cells in humans. Our study identified >200 new T cell epitopes derived from both canonical and novel ORFs, highlighting the substantial breadth of anti-CMV T cell response and providing new targets for vaccine design.

Perspectives of women on screening and prevention of CMV in pregnancy

OBJECTIVE

To assess the choice and attitude of pregnant women regarding CMV serological screening and CMV prevention behaviors in pregnancy.

STUDY DESIGN

In this cross-sectional study, pregnant women were recruited in a single center during routine prenatal screening tests at 11-16 weeks. Participants filled out a questionnaire assessing knowledge about congenital CMV (cCMV) infection, risk perception and willingness to have CMV serological screening as well as their attitude toward CMV prevention behaviors.

RESULTS

Among 234 pregnant women, 74.4 % (95 % confidence interval: 68.8-80.0 %) wanted CMV serological screening in pregnancy. The factors significantly associated with the desire for screening were perceived risk and perceived severity of cCMV. An informed choice regarding CMV screening (value-consistent, based on good knowledge and deliberated) was performed by 54 % of women who chose the screening and 30 % of women who declined the screening (p = 0.039). The median scores regarding attitudes toward CMV prevention behaviors were 3.7/5 for avoiding sharing behaviors and 4.0/5 for not kissing a child on the lips.

CONCLUSION

The majority of pregnant women want to have CMV serological screening once informed about congenital CMV infection. New tools need to be developed to allow for informed choice regarding CMV serological screening in pregnancy.

Maternal cytomegalovirus immune status and hearing loss outcomes in congenital cytomegalovirus-infected offspring

Objectives

The purpose of this study is to determine the relationship between maternal primary and recurrent CMV infection during pregnancy, symptoms at birth in the newborn, and long term hearing loss through18 years of age.

Patients and methods

237 mother-infant pairs in the Houston, Texas area identified through maternal CMV IgG and IgM antibody serologic screening and newborn screening using urine CMV culture to identify congenital CMV infection were enrolled in the Houston Congenital CMV Longitudinal Study. Mothers were categorized as having primary or recurrent or unknown maternal CMV infections, and newborns were categorized at birth as having symptomatic or asymptomatic congenital CMV infection, or as uninfected controls. All three newborn groups were followed longitudinally with serial hearing evaluations up to 18 years of age. The relationship between type of maternal CMV infection, newborn classification, and the occurrence of hearing loss over time was determined through Kaplan-Meier survival analysis, life table analysis, and a simulated ascertainment of maternal infection type for the unknown categories.

Results

Of 77 newborns with symptomatic congenital CMV infection, 12 (16%) of mothers had a primary CMV infection during pregnancy; 4 (5%) had a non-primary infection, and the type of infection in 48 (79%) could not be determined and were classified as unknown type of maternal infection. Fifty Seven (74%) of the 77 symptomatic children had hearing loss by 18 years of age, including 9 of the 12 (75%) who were born to mothers with primary infection and 48 (79%) of the 61 with unknown type of maternal infection. Of the 109 newborns with asymptomatic congenital CMV infection, 51 (47%) were born to mothers with a primary CMV infection during pregnancy, 18 (17%) to mothers with a recurrent infection; and 40 (37%) had unknown type of infection. Of these 109 asymptomatic cases, 22 (20%) developed hearing loss, including 14 out of 51 (28%) of those born to mothers with primary infection, two out of the 18 (11%) born to mothers with recurrent infection, and 6 out of the 40 (15%) to mothers of unknown infection type. Of the 51 uninfected newborn controls, 10 (20%) of mothers had a primary CMV infection during pregnancy, 5 (10%) had a non-primary infection, 10 (20%) were never infected, and 26 (51%) were assigned unknown type of infection. Three controls (6%) developed hearing loss, with 1 being born to a mother with primary infection and 1 to a mother never infected with CMV.

Conclusions

Both primary and non-primary maternal CMV infections during pregnancy resulted in symptomatic and asymptomatic congenital CMV infection. Symptomatic congenital CMV infection was more likely to occur after primary maternal CMV infection. Sensorineural hearing loss occurred in children born to mothers with both primary and non-primary CMV infections, and in both asymptomatic and symptomatic congenital CMV infection, but was more common after maternal primary infection. Most, but not all, hearing loss in children with cCMV associated hearing loss was first detected within the first year of life.

Immunization with Human Cytomegalovirus Core Fusion Machinery and Accessory Envelope Proteins Elicit Strong Synergistic Neutralizing Activities

Human cytomegalovirus (HCMV) core fusion machinery proteins gB and gH/gL, and accessory proteins UL128/UL130/UL131A, are the key envelope proteins that mediate HCMV entry into and infection of host cells. To determine whether these HCMV envelope proteins could elicit neutralizing activities synergistically, we immunized rabbits with individual or various combinations of these proteins adsorbed to aluminum hydroxide mixed with CpG-ODN. We then analyzed serum neutralizing activities with multiple HCMV laboratory strains and clinical isolates. HCMV trimeric gB and gH/gL elicited high and moderate titers of HCMV neutralizing activity, respectively. HCMV gB in combination with gH/gL elicited up to 17-fold higher HCMV neutralizing activities compared to the sum of neutralizing activity elicited by the individual proteins analyzed with both fibroblasts and epithelial cells. HCMV gB+gH/gL+UL128/UL130/UL131A in combination increased the neutralizing activity up to 32-fold compared to the sum of neutralizing activities elicited by the individual proteins analyzed with epithelial cells. Adding UL128/UL130/UL131A to gB and gH/gL combination did not increase further the HCMV neutralizing activity analyzed with fibroblasts. These data suggest that the combination of HCMV core fusion machinery envelope proteins gB+gH/gL or the combination of gB and pentameric complex could be ideal vaccine candidates that would induce optimal immune responses against HCMV infection.

Salivary cytomegalovirus excretion in children in daycare centers and home care facilities in Japan

Cytomegalovirus (CMV) is the most common cause of congenital viral infection in developed countries. The incidence of in utero infection is high in pregnant women who are CMV antibody negative. An important infection route is in contact with children who attend daycare centers (DCCs). However, there are few reports on CMV excretion in children at DCCs in Japan. Saliva samples were collected twice during a 6-month interval from children attending one of two DCCs (DCC1 and DCC2 groups) and from those receiving home care (HC group). The samples were used to quantitatively evaluate CMV using real-time polymerase chain reaction and to determine glycoprotein B (gB) genotypes. The percentage of subjects who demonstrated CMV excretion in either the first or second sample collection was higher in the DCC groups than in the HC group, with incidences in the DCC1, DCC2, and HC groups of 53.4% (n = 47 of 88), 23.9% (n = 16 of 67), and 12.7% (n = 7 of 55), respectively. Compared with the DCC2 group, the DDC1 group had a higher incidence of CMV excretion and included more subjects with a high number of viral copies. In both DCC groups, the incidence of CMV excretion was highest in children younger than 3 years of age. In all three groups, the predominant genotypes were gB1 and gB3. Based on the higher incidence of CMV excretion in the DCC groups compared with the HC group, it is considered that CMV infection is acquired mainly in DCCs in children under the age of 3.

Immunization of Rabbits with Recombinant Human Cytomegalovirus Trimeric versus Monomeric gH/gL Protein Elicits Markedly Higher Titers of Antibody and Neutralization Activity

Congenital human cytomegalovirus (HCMV) infection and HCMV infection of immunosuppressed patients cause significant morbidity and mortality, and vaccine development against HCMV is a major public health priority. HCMV envelope glycoproteins gB, gH, and gL, which constitute the core fusion machinery, play critical roles in HCMV fusion and entry into host cells. HCMV gB and gH/gL have been reported to elicit potent neutralizing antibodies. Recently, the gB/gH/gL complex was identified in the envelope of HCMV virions, and 16–50% of the total gH/gL bound to gB, forming the gB/gH/gL complex. These findings make the gB/gH/gL a unique HCMV vaccine candidate. We previously reported the production of HCMV trimeric gB and gH/gL heterodimers, and immunization with a combination of trimeric gB and gH/gL heterodimers elicited strong synergistic HCMV-neutralizing activity. To further improve the immunogenicity of gH/gL, we produced trimeric gH/gL. Rabbits immunized with HCMV trimeric gH/gL induced up to 38-fold higher serum titers of gH/gL-specific IgG relative to HCMV monomeric gH/gL, and elicited ~10-fold higher titers of complement-dependent and complement-independent HCMV-neutralizing activity for both epithelial cells and fibroblasts. HCMV trimeric gH/gL in combination with HCMV trimeric gB would be a novel promising HCMV vaccine candidate that could induce highly potent neutralizing activities.

Development of novel vaccines against human cytomegalovirus

Congenital human cytomegalovirus (HCMV) infection and HCMV infection of the immunosuppressed patients cause significant morbidity and mortality, and vaccine development against HCMV is a major public health priority. Efforts to develop HCMV vaccines have been ongoing for 50 y, though no HCMV vaccine has been licensed; encouraging and promising results have obtained from both preclinical and clinical trials. HCMV infection induces a wide range of humoral and T cell-mediated immune responses, and both branches of immunity are correlated with protection. In recent years, there have been novel approaches toward the development of HCMV vaccines and demonstrated that vaccine candidates could potentially provide superior protection over natural immunity acquired following HCMV infection. Further, rationally designed HCMV protein antigens that express native conformational epitopes could elicit optimal immune response. HCMV vaccine candidates, using a multi-antigen approach, to maximize the elicited protective immunity will most likely be successful in development of HCMV vaccine.

Genotyping of Cytomegalovirus from Symptomatic Infected Neonates in Iraq

Among all other viruses, human cytomegalovirus (HCMV) is the most frequent cause of congenital infection worldwide. Strain variation in HCMV may predict severity or outcome of congenital HCMV disease. Previous studies have associated a particular genotype with specific sequelae or more severe illness, but the results were contradictory. There are no previous studies addressing the genotype of HCMV in Iraq. Therefore, the present study is aimed at molecular detection and genotyping of HCMV isolated from symptomatic congenitally/perinatally infected neonates. This prospective study comprised 24 serum samples from symptomatic neonates with congenital/perinatal infection. Viral DNA was extracted from these serum samples; nested polymerase chain reaction was used to amplify the HCMV gB (UL55) gene. Polymerase chain reaction products of the second round of amplification were subjected to direct Sanger sequencing. Bioedit and MEGA5 software (EMBL-EBI, Hinxton, Cambridgeshire, UK) were used for alignment and construction of a phylogenetic tree. Human cytomegalovirus DNA was detected in 23 of 24 samples (95.8%). According to the phylogenetic analysis, three genotypes of the virus were identified; gB1, gB2, and gB3 genotypes. However, the gB4 genotype was not detected. Human cytomegalovirus gB3 was the most frequent genotype: 14 of 24 (58.33%) among symptomatic infected infants, followed by gB1 (6/24; 25%) and gB2 (4/24; 16.67%). A mixed HCMV infection with gB3/gB1 was detected in only one case. Human cytomegalovirus gB3 was the most predominant genotype among symptomatic congenitally/perinatally HCMV-infected neonates. No association was found between B3 genotype and specific clinical presentation. Jaundice was the most common clinical feature among symptomatically infected neonates, followed by hepatosplenomegaly.

Novel trimeric human cytomegalovirus glycoprotein B elicits a high-titer neutralizing antibody response

Human cytomegalovirus (HCMV) is a major cause of disability in congenitally infected infants and in the immunosuppressed. There is currently no licensed prophylactic HCMV vaccine. The HCMV envelope glycoprotein B (gB) is considered a major vaccine target antigen based on its critical role in mediating viral-host cell fusion and thus viral entry. The natural conformation of HCMV gB within the viral envelope is a trimer, but there has been no reported success in producing a recombinant trimeric gB suitable for vaccine use. Phase II clinical trials of a monomeric recombinant gB protein demonstrated 50% efficacy in preventing HCMV infection in seronegative women of reproductive age, and in reducing viremia in solid organ transplantation recipients. We now report the production of a uniformly trimeric recombinant HCMV gB protein in Chinese ovary cells, as demonstrated by Western blot analysis under modified non-reducing conditions and size exclusion chromatography with multi-angle scattering. Immunization of mice with trimeric HCMV gB induced up to 11-fold higher serum titers of total gB-specific IgG relative to monomeric HCMV gB using Alum + CpG as adjuvants. Further, trimeric HCMV gB elicited 50-fold higher complement-independent and 20-fold higher complement-dependent HCMV neutralizing titers compared to monomeric HCMV gB using the fibroblast cell line, MRC-5, and up to 6-fold higher complement-independent and -dependent HCMV neutralizing titers using the epithelial cell line, ARPE-19. The markedly enhanced HCMV neutralizing activity in response to trimeric HCMV gB was also observed using an additional four distinct clinical HCMV isolates. These data support a role for trimeric HCMV gB as an important component for clinical testing of a prophylactic HCMV vaccine.

Update on treatment of cytomegalovirus infection in pregnancy and of the newborn with congenital cytomegalovirus

PURPOSE OF REVIEW

The purpose of this review is to assess the recent studies of therapy of pregnant women and neonates, aimed at preventing the consequences of congenital cytomegalovirus (CMV) infection.

RECENT FINDINGS

A recent randomized controlled trial of treatment of CMV during pregnancy with hyperimmune globulin did not show significant efficacy in prevention of foetal infection and morbidity, although there was a trend towards improvement with treatment. Trials of antiviral therapy of the mother during pregnancy have involved small numbers only, confounded by ethical and practical difficulties, and further studies are needed to demonstrate whether or not antivirals are useful and well tolerated in this setting.Antiviral treatment of neonatal CMV acquired congenitally has been studied in well controlled trials and the antiviral valganciclovir has shown efficacy in reducing the more severe outcomes. Trials are ongoing of the use of antivirals in less severe disease, although results are likely to take several years.

SUMMARY

Congenital CMV infection is the most frequent cause of congenital malformation in developed countries, with a symptomatic prevalence of 0.64% of all live births. Infection may result in neurodevelopmental delay, foetal or neonatal death, and most frequently, sensorineural hearing loss. Successful control of viral infections during pregnancy and in the newborn period is essential in reducing early and late morbidity and mortality. Control of congenital CMV infection may be via primary prevention methods such as reducing contact with the pathogen, improved hygiene - both for the pregnant mother and for the neonate, or secondary prevention via reduction of vertical transmission from mother to foetus and reduction in consequences of infection by treatment of infected pregnant women and infected neonates.

The Serological Evidence of Cytomegalovirus Infection as a Potent Aetiological Factor for Cleft Lip/Palate, Mental Retardation and Deafness

INTRODUCTION

Congenital Cytomegalovirus (CCMV) infection is estimated to occur in 0.5% to 2% of all deliveries across the world. According to the available literature about Human Cytomegalovirus (HCMV) infected children, 0.5% to 1% acquire Cytomegalovirus (CMV) in utero, 40% acquire the infection within the first decade of life, between 15% to 70% acquire CMV infection in group day care settings and continue to shed the virus for 6 to 48 months after primary infection. Although, 90% of the infected infants are clinically asymptomatic at birth, shreds of evidence show that these infants are at risk for audiological, neurological, and developmental sequelae. Despite this, HCMV still remains undetected due to silent or asymptomatic nature of the virus.

AIM

The present study was aimed to test the hypothesis that HCMV can be a potential aetiologic factor in the development of cleft lip/palate, mental retardation and deafness.

MATERIALS AND METHODS

The study was carried out in a controlled setting under strict aseptic conditions. Blood samples were collected from 80 children, who were selected strictly adhering to the inclusion criteria and were divided into four groups containing 20 children each. Group 1: 20 children with cleft lip/palate, Group 2: 20 mentally retarded children, Group 3: 20 completely deaf children and Group 4: 20 normal Children (control). The samples were tested for HCMV-specific Immunoglobulin G (IgG) and Immunoglobulin M (IgM) antibodies by using solid phase enzyme-linked immunosorbent assay and the obtained data were analysed statistically using ANOVA and Post-Hoc Tukey's tests.

RESULTS

In the study group (Group1, 2 and 3) children, the overall positivity for HCMV- specific IgG was 100% and 5% borderline to IgM antibodies whereas in the control group (Group 4) it was 80% negative to HCMV- specific IgG and 100% negative to IgM antibodies.

CONCLUSION

From the observations noted in the present study, HCMV could be suggested as the potent aetiologic factor in the development of cleft lip/palate, mental retardation and deafness.

Congenital cytomegalovirus infection in pregnancy and the neonate: consensus recommendations for prevention, diagnosis, and therapy

Congenital cytomegalovirus is the most frequent, yet under-recognised, infectious cause of newborn malformation in developed countries. Despite its clinical and public health importance, questions remain regarding the best diagnostic methods for identifying maternal and neonatal infection, and regarding optimal prevention and therapeutic strategies for infected mothers and neonates. The absence of guidelines impairs global efforts to decrease the effect of congenital cytomegalovirus. Data in the literature suggest that congenital cytomegalovirus infection remains a research priority, but data are yet to be translated into clinical practice. An informal International Congenital Cytomegalovirus Recommendations Group was convened in 2015 to address these questions and to provide recommendations for prevention, diagnosis, and treatment. On the basis of consensus discussions and a review of the literature, we do not support universal screening of mothers and the routine use of cytomegalovirus immunoglobulin for prophylaxis or treatment of infected mothers. However, treatment guidelines for infected neonates were recommended. Consideration must be given to universal neonatal screening for cytomegalovirus to facilitate early detection and intervention for sensorineural hearing loss and developmental delay, where appropriate. The group agreed that education and prevention strategies for mothers were beneficial, and that recommendations will need continual updating as further data become available.

Seroprevalence of cytomegalovirus infection in France in 2010

Cytomegalovirus (CMV) infection remains the leading cause of congenital virus infection in developed countries. Measuring the national prevalence of this infection, especially among women of childbearing age, is of great value to estimate the risk of congenital CMV infection, as well as to identify risk groups that should be targeted for behavioural interventions and/or vaccination once a CMV vaccine finally becomes available. In order to fulfil these objectives, a seroprevalence survey was conducted in 2010, using a nationally representative, population-based sample of 2536 people aged between 15 and 49 years, living in metropolitan France and attending private microbiological laboratories for blood testing. All blood samples were analysed in the same laboratory and screened for CMV-specific IgG using an enzyme-linked immunoassay technique (Elisa PKS Medac Enzyme immunoassay). The overall point estimate of CMV infection seroprevalence for individuals aged 15-49 years was 41.9%. The estimates were higher in women than in men (respectively 45.6% and 39.3%), and people born in a non-Western country were more likely to be CMV seropositive than those born in France or in another Western country (93.7% vs. 37.7%). Our results showed that a substantial percentage of women of childbearing age in France are CMV seronegative and therefore at risk of primary CMV infection during pregnancy. Educational measures and future vaccine are key issues to prevent infection in pregnant women and congenital CMV disease.

Congenital Cytomegalovirus Infection: Prognostic Value of Maternal DNAemia at Amniocentesis

BACKGROUND

Human Cytomegalovirus (HCMV) is the most common cause of childhood hearing loss and can lead to neurodevelopmental delay. To date, few studies have examined the correlation between maternal viremia and congenital HCMV infection. The aim of our study was to ascertain if HCMV DNA in the peripheral blood of pregnant women with primary HCMV infection at the time of amniocentesis may have a prognostic value in terms of congenital infection and neonatal symptomatic disease.

METHODS

We performed a prospective observational study of pregnant women referred to our maternal-fetal medicine division with suspected HCMV infection. Primary infection was diagnosed based on seroconversion for HCMV and/or HCMV immunoglobulin M-positive and low or moderate HCMV immunoglobulin G avidity. At the time of amniocentesis, maternal blood samples were collected and analyzed by means of real-time polymerase chain reaction to determine the presence of viral DNAemia. Fetuses and newborns were evaluated for the presence of congenital infection and symptomatic disease.

RESULTS

A total of 239 pregnant women were enrolled; 32 blood samples (13.4%) were positive, and 207 (86.6%) were negative for HCMV DNA. The overall rate of transmission was 23.4%. Fifteen infected patients (26.8%) were symptomatic. Vertical transmission occurred in 14 women (43.8%) with positive and 42 (20.3%) with negative results for HCMV DNAemia (P = .006; odds ratio, 3.06; 95% confidence interval, 1.41-6.64). Symptomatic infection occurred in 6 (42.9%) infected fetuses or newborns from women with and in 9 (21.4%) from women without viral DNAemia (P = .16).

CONCLUSION

Maternal viremia at amniocentesis is associated with a 3-fold greater chance of congenital infection, but it is not correlated with symptomatic disease.

Impact of a cytomegalovirus kinase inhibitor on infection and neuronal progenitor cell differentiation

Human cytomegalovirus (HCMV) is the leading cause of congenital infections. Symptomatic newborns present with a range of sequelae including disorders of the CNS such as visual impairment, microcephaly, mental retardation and hearing loss. HCMV congenital infection causes gross changes in brain morphology and disturbances in glial and neuronal distribution, number and migration. In these studies, we have evaluated the effectiveness of the antiviral maribavir in inhibiting HCMV infections of ES cell-derived neuronal progenitor cells (NPC). We used EZ-spheres generated from H9 ES cells which are pre-rosette NPCs that retain long-term potential to differentiate into diverse central and peripheral neural lineages following directed differentiation. Our results demonstrate that the maribavir disrupts HCMV replication and viral yield in undifferentiated EZ-sphere-derived NPCs. In addition, we observed that maribavir limits HCMV replication and reduces the percentage of infected cells during differentiation of NPCs. Finally, early steps in differentiation are maintained during infection by treating with maribavir, likely an indirect effect resulting from decreased viral spread. Future studies of NPC proliferation and differentiation during infection treated with maribavir could provide the impetus for studying maribavir as an antiviral agent for congenital HCMV disease.

Congenital cytomegalovirus infection in pregnancy: a review of prevalence, clinical features, diagnosis and prevention

Human cytomegalovirus (CMV) is under-recognised, despite being the leading infectious cause of congenital malformation, affecting ~0.3% of Australian live births. Approximately 11% of infants born with congenital CMV infection are symptomatic, resulting in clinical manifestations, including jaundice, hepatosplenomegaly, petechiae, microcephaly, intrauterine growth restriction and death. Congenital CMV infection may cause severe long-term sequelae, including progressive sensorineural hearing loss and developmental delay in 40-58% of symptomatic neonates, and ~14% of initially asymptomatic infected neonates. Up to 50% of maternal CMV infections have nonspecific clinical manifestations, and most remain undetected unless specific serological testing is undertaken. The combination of serology tests for CMV-specific IgM, IgG and IgG avidity provide improved distinction between primary and secondary maternal infections. In pregnancies with confirmed primary maternal CMV infection, amniocentesis with CMV-PCR performed on amniotic fluid, undertaken after 21-22 weeks gestation, may determine whether maternofetal virus transmission has occurred. Ultrasound and, to a lesser extent, magnetic resonance imaging are valuable tools to assess fetal structural and growth abnormalities, although the absence of fetal abnormalities does not exclude fetal damage. Diagnosis of congenital CMV infection at birth or in the first 3 weeks of an infant's life is crucial, as this should prompt interventions for prevention of delayed-onset hearing loss and neurodevelopmental delay in affected infants. Prevention strategies should also target mothers because increased awareness and hygiene measures may reduce maternal infection. Recognition of the importance of CMV in pregnancy and in neonates is increasingly needed, particularly as therapeutic and preventive interventions expand for this serious problem.

Current controversies in diagnosis, management, and prevention of congenital cytomegalovirus: updates for the pediatric practitioner

Congenital cytomegalovirus (CMV) infection has been called "the elephant in our living room" because it is a major public health problem that for decades has been unrecognized and unaddressed. Congenital CMV infection is a common cause of sensorineural hearing loss, vision loss, neurodevelopment disabilities, liver disease, and growth failure. Diagnostic tests are now widely available to identify newborns with congenital CMV infection, congenitally infected newborns now can be easily assessed for evidence of organ involvement, and there are now antiviral treatments and other interventions available to improve the outcome in children with congenital CMV disease. A licensed vaccine to prevent CMV infection is not yet available; however, a "CMV knowledge vaccine," composed of "an ounce of CMV awareness and three simple precautions" and that is endorsed by the Centers for Disease Control and Prevention is available for pregnant women who wish to reduce their contact with potentially CMV-infected secretions and therefore reduce their risk of acquiring CMV during pregnancy. Medical experts in the field of congenital CMV have been called upon for a consensus statement for diagnosis and treatment, and nonprofit organizations of families affected by congenital CMV from around the world have formed a collaborative coalition to facilitate the spread of CMV knowledge and awareness.

The Milieu Intérieur study - an integrative approach for study of human immunological variance

The Milieu Intérieur Consortium has established a 1000-person healthy population-based study (stratified according to sex and age), creating an unparalleled opportunity for assessing the determinants of human immunologic variance. Herein, we define the criteria utilized for participant enrollment, and highlight the key data that were collected for correlative studies. In this report, we analyzed biological correlates of sex, age, smoking-habits, metabolic score and CMV infection. We characterized and identified unique risk factors among healthy donors, as compared to studies that have focused on the general population or disease cohorts. Finally, we highlight sex-bias in the thresholds used for metabolic score determination and recommend a deeper examination of current guidelines. In sum, our clinical design, standardized sample collection strategies, and epidemiological data analyses have established the foundation for defining variability within human immune responses.

Cross-sectional study of cytomegalovirus shedding and immunological markers among seropositive children and their mothers

Background

Congenital cytomegalovirus (CMV) is the leading infectious cause of birth defects in the United States. To better understand factors that may influence CMV transmission risk, we compared viral and immunological factors in healthy children and their mothers.

Methods

We screened for CMV IgG antibodies in a convenience sample of 161 children aged 0-47 months from the Atlanta, Georgia metropolitan area, along with 32 mothers of children who screened CMV-seropositive. We assessed CMV shedding via PCR using saliva collected with oral swabs (children and mothers) and urine collected from diapers using filter paper inserts (children only).

Results

CMV IgG was present in 31% (50/161) of the children. Half (25/50) of seropositive children were shedding in at least one fluid. The proportion of seropositive children who shed in saliva was 100% (8/8) among the 4-12 month-olds, 64% (9/14) among 13-24 month-olds, and 40% (6/15) among 25-47 month-olds (P for trend = 0.003). Seropositive mothers had a lower proportion of saliva shedding (21% [6/29]) than children (P < 0.001). Among children who were shedding CMV, viral loads in saliva were significantly higher in younger children (P <0.001); on average, the saliva viral load of infants (i.e., <12 months) was approximately 300 times that of two year-olds (i.e., 24-35 months). Median CMV viral loads were similar in children's saliva and urine but were 10-50 times higher (P < 0.001) than the median viral load of the mothers' saliva. However, very high viral loads (> one million copies/mL) were only found in children's saliva (31% of those shedding); children's urine and mothers' saliva specimens all had fewer than 100,000 copies/mL. Low IgG avidity, a marker of primary infection, was associated with younger age (p = 0.03), higher viral loads in saliva (p = 0.02), and lower antibody titers (p = 0.005).

Conclusions

Young CMV seropositive children, especially those less than one year-old may present high-risk CMV exposures to pregnant women, especially via saliva, though further research is needed to see if this finding can be generalized across racial or other demographic strata.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-014-0568-2) contains supplementary material, which is available to authorized users.

Universal newborn screening for congenital CMV infection: what is the evidence of potential benefit?

Congenital CMV infection is a leading cause of childhood disability. Many children born with congenital CMV infection are asymptomatic or have nonspecific symptoms and therefore are typically not diagnosed. A strategy of newborn CMV screening could allow for early detection and intervention to improve clinical outcomes. Interventions might include antiviral drugs or nonpharmaceutical therapies such as speech-language therapy or cochlear implants. Using published data from developed countries, we analyzed existing evidence of potential benefit that could result from newborn CMV screening. We first estimated the numbers of children with the most important CMV-related disabilities (i.e. hearing loss, cognitive deficit, and vision impairment), including the age at which the disabilities occur. Then, for each of the disabilities, we examined the existing evidence for the effectiveness of various interventions. We concluded that there is good evidence of potential benefit from nonpharmaceutical interventions for children with delayed hearing loss that occurs by 9 months of age. Similarly, we concluded that there is fair evidence of potential benefit from antiviral therapy for children with hearing loss at birth and from nonpharmaceutical interventions for children with delayed hearing loss occurring between 9 and 24 months of age and for children with CMV-related cognitive deficits. We found poor evidence of potential benefit for children with delayed hearing loss occurring after 24 months of age and for children with vision impairment. Overall, we estimated that in the United States, several thousand children with congenital CMV could benefit each year from newborn CMV screening, early detection, and interventions.

In vitro combination of anti-cytomegalovirus compounds acting through different targets: role of the slope parameter and insights into mechanisms of Action

Conventional therapy for human cytomegalovirus (CMV) relies on inhibition of the viral DNA polymerase. Ganciclovir (GCV) is the first-line therapy, but when GCV-resistant strains emerge, alternative therapies are extremely limited and are associated with significant toxicities. Combination of anti-CMV agents that act on different targets or stages of virus replication has not been well studied, mostly because of the limited number of anti-CMV agents. We report our investigation of combinations of agents that inhibit CMV by targeting the viral DNA polymerase, cellular kinases, or other cell/virus mechanisms yet to be discovered. The selected compounds differed by the slopes of their dose-response curve: compounds with a slope of 1 (GCV) representing one target or noncooperativity and compounds with high slopes indicating positive cooperativity. Analysis of anti-CMV drug combinations using the Bliss model (which accounts for the slope parameter) distinguished between combinations with synergistic, antagonistic, and additive activities. The combination of GCV and foscarnet was slightly synergistic; strong synergism was found when GCV was used with artemisinin-derived monomers or dimers or the MEK inhibitor U0126. The combination of GCV and cardiac glycosides (digoxin, digitoxin, and ouabain) was additive. The monomeric artemisinin artesunate was synergistic when combined with U0126 or the multikinase inhibitor sunitinib. However, the combination of artemisinin-derived dimers (molecular weights, 606 and 838) and U0126 or sunitinib was antagonistic. These results demonstrate that members of a specific drug class show similar patterns of combination with GCV and that the slope parameter plays an important role in the evaluation of drug combinations. Lastly, antagonism between different classes of CMV inhibitors may assist in target identification and improve the understanding of CMV inhibition by novel compounds.

[Usefulness of a real-time quantitative polymerase-chain reaction (PCR) assay for the diagnosis of congenital and postnatal cytomegalovirus infection]

INTRODUCTION

Cytomegalovirus (CMV) is the main virus causing congenital and postnatal infections in the pediatric population. The aim of this study is to evaluate the usefulness of a quantitative real-time PCR in the diagnosis of these infections using urine as a single sample.

PATIENTS AND METHODS

We studied all the urine samples of newborns (< 7 days) with suspected congenital infection, and urine of patients with suspected postnatal infection (urine negative at birth). Urines were simultaneously studied by cell culture, qualitative PCR (PCRc), and quantitative real-time PCR (PCRq).

RESULTS

We analyzed 332 urine samples (270 to rule out congenital infection and 62 postnatal infections). Of the first, 22 were positive in the PCRq, 19 in the PCRc, and 17 in the culture. PCRq had a sensitivity of 100%, on comparing the culture with the rest of the techniques. Using the PCRq as a reference method, culture had a sensitivity of 77.2%, and PCRc 86.3%. In cases of postnatal infection, PCRq detected 16 positive urines, the PCRq 12, and the cell culture 10. The urines showed viral loads ranging from 2,178 to 116,641 copies/ml.

CONCLUSIONS

The genomic amplification technique PCRq in real time was more sensitive than the other techniques evaluated. This technique should be considered as a reference (gold standard), leaving the cell culture as a second diagnostic level. The low cost and the automation of PCRq would enable the screening for CMV infection in large neonatal and postnatal populations.

The "silent" global burden of congenital cytomegalovirus

Human cytomegalovirus (CMV) is a leading cause of congenital infections worldwide. In the developed world, following the virtual elimination of circulating rubella, it is the commonest nongenetic cause of childhood hearing loss and an important cause of neurodevelopmental delay. The seroprevalence of CMV in adults and the incidence of congenital CMV infection are highest in developing countries (1 to 5% of births) and are most likely driven by nonprimary maternal infections. However, reliable estimates of prevalence and outcome from developing countries are not available. This is largely due to the dogma that maternal preexisting seroimmunity virtually eliminates the risk for sequelae. However, recent data demonstrating similar rates of sequelae, especially hearing loss, following primary and nonprimary maternal infection have underscored the importance of congenital CMV infection in resource-poor settings. Although a significant proportion of congenital CMV infections are attributable to maternal primary infection in well-resourced settings, the absence of specific interventions for seronegative mothers and uncertainty about fetal prognosis have discouraged routine maternal antibody screening. Despite these challenges, encouraging results from prototype vaccines have been reported, and the first randomized phase III trials of prenatal interventions and prolonged postnatal antiviral therapy are under way. Successful implementation of strategies to prevent or reduce the burden of congenital CMV infection will require heightened global awareness among clinicians and the general population. In this review, we highlight the global epidemiology of congenital CMV and the implications of growing knowledge in areas of prevention, diagnosis, prognosis, and management for both low (50 to 70%)- and high (>70%)-seroprevalence settings.

Awareness of and behaviors related to child-to-mother transmission of cytomegalovirus

OBJECTIVE

Congenital cytomegalovirus (CMV) infection is a common cause of hearing loss and intellectual disability. We assessed CMV knowledge and the frequency of women's behaviors that may enable CMV transmission to inform strategies for communicating prevention messages to women.

METHODS

We analyzed survey responses from 4184 participants (2181 women, 2003 men) in the 2010 HealthStyles survey, a national mail survey designed to be similar to the United States population.

RESULTS

Only 7% of men and 13% of women had heard of congenital CMV. Women with children under age 19 (n=918) practiced the following risk behaviors at least once per week while their youngest child was still in diapers: kissing on the lips (69%), sharing utensils (42%), sharing cups (37%), and sharing food (62%). Women practiced protective, hand cleansing behaviors most of the time or always after: changing a dirty diaper (95%), changing a wet diaper (85%), or wiping the child's nose (65%), but less commonly after handling the child's toys (26%).

CONCLUSIONS

Few women are aware of CMV and most regularly practice behaviors that may place them at risk when interacting with young children. Women should be informed of practices that can reduce their risk of CMV infection during pregnancy.

Awareness of and attitudes toward congenital cytomegalovirus infection among pregnant women in Singapore

OBJECTIVE

To assess the level of awareness of congenital cytomegalovirus (CMV) infection and attitudes toward prenatal CMV serologic testing among pregnant women.

METHODS

A questionnaire was distributed to pregnant women who attended a specialist outpatient clinic at Singapore General Hospital, Singapore, between September and December 2010.

RESULTS

Among 200 respondents, 40 (20.0%) were aware of CMV. Healthcare workers were more likely to be aware of CMV (odds ratio 6.91, confidence interval 2.14-22.30; P=0.001). Most respondents found it "very" or "somewhat" easy to adhere to standard guidelines for primary prevention of CMV. Among the respondents, 62.0% (124/200) would like to be given the option of prenatal CMV screening and 72.0% (144/200) were keen to be screened. On multivariate analysis, respondents who were keen to undergo serologic screening for CMV were not more likely to consider invasive testing or termination of pregnancy should the test results demonstrate primary maternal CMV infection.

CONCLUSION

Pregnant women who were keen to undergo CMV testing demonstrated attitudes toward invasive testing and termination of pregnancy that were not significantly different from those of women who would refuse testing. Patient choice and expectations should be considered in the implementation of preventive measures against congenital CMV.

Extraction of DNA from dried blood in the diagnosis of congenital CMV infection

Viral DNA detection in dried blood spotted on filter paper, dried blood spots (DBS), is valuable in the diagnosis of viral infections, with at the moment congenital cytomegalovirus (CMV) being the most common application. CMV detection in clinical samples taken within the first 2-3 weeks after birth differentiates congenital CMV infection from the in general harmless postnatal acquired cytomegalovirus infection. DBS render the possibility to diagnose congenital CMV infection retrospectively, e.g., when late-onset hearing loss, the most frequently encountered symptom of congenital CMV infection, becomes manifest. Additionally, CMV DNA detection in DBS can be of usage in recently advocated newborn screening on congenital CMV infection. The procedure of CMV DNA detection in DBS consists of two separate steps: (1) DNA extraction from the DBS, followed by (2) CMV DNA amplification. Here, we describe two efficient methods for the extraction of DNA from DBS. Sensitivity, specificity, and applicability of the methods for high-throughput usage are discussed.

Cytomegalovirus survival on common environmental surfaces: opportunities for viral transmission

Congenital cytomegalovirus (CMV) affects ~1 of 150 births and is a leading cause of hearing loss and intellectual disability. It has been suggested that transmission may occur via contaminated surfaces. CMV AD169 in filtered human saliva, applied to environmental surfaces, was recovered at various time points. Samples were evaluated by culture and real-time polymerase chain reaction. CMV was found viable on metal and wood to 1 hour, glass and plastic to 3 hours, and rubber, cloth, and cracker to 6 hours. CMV was cultured from 83 of 90 wet and 5 of 40 dry surfaces. CMV was more likely to be isolated from wet, highly absorbent surfaces at earlier time points.

Review of cytomegalovirus shedding in bodily fluids and relevance to congenital cytomegalovirus infection

Congenital cytomegalovirus (CMV) infections are a leading cause of sensorineural hearing loss (SNHL) and neurological impairment. Congenital transmission of CMV can occur with maternal primary infection, reactivation, or reinfection during pregnancy. We reviewed studies of CMV shedding in bodily fluids (defined as CMV detected by culture or CMV DNA detected by polymerase chain reaction). Following diagnosis at birth, children with congenital CMV infection exhibited the highest prevalences of CMV shedding (median = 80%, number of sample population prevalences [N] = 6) and duration of shedding, with a steep decline by age five. Healthy children attending day care shed more frequently (median = 23%, N = 24) than healthy children not attending day care (median = 12%, N = 11). Peak shedding prevalences in children occurred at 1-2 years of age, confirming that young children are the key transmission risk for pregnant women. CMV shedding among children was more prevalent in urine specimens than in oral secretions (median prevalence difference = 11.5%, N = 12). Adults with risk factors such as STD clinic attendance had higher shedding prevalences (median = 22%, N = 20) than adults without risk factors (median = 7%, N = 44). In adults with risk factors, CMV was shed more frequently in urine; in adults without risk factors genital shedding was most common. The prevalence of CMV shedding in nine sample populations of pregnant women increased with advancing gestation. In seven sample populations of children with congenital CMV infection, higher viral load at birth was consistently associated with an elevated risk of SNHL. Higher CMV viral load at birth also consistently correlated with the presence of symptoms of congenital CMV at birth. Published 2011. This article is a US Government work and is in the public domain in the USA.

Human cytomegalovirus infection and clinical status of infants born to human immunodeficiency virus type 1 infected mothers

OBJECTIVE

Human cytomegalovirus (HCMV) is one of the most common congenital infections worldwide and a frequent opportunistic infection that aggravates the condition of human immunodeficiency virus (HIV)-infected patients. The aim of the study was to evaluate the frequency and factors influencing HCMV infection among infants of HIV-positive women.

METHODS

The study included 35 infants born to HIV-1-infected mothers examined for congenital infections. Children were evaluated for human immunodeficiency virus type 1 (HIV-1), HCMV, and HCV infection by serological and molecular methods.

RESULTS

HIV-1 infection was found in one child whose mother did not receive antiretroviral treatment during pregnancy, and HCV infection in another infant. HCMV-DNA in the urine was present in 13/35 infants (37.14%) on the 10th day and 24/35 infants (68.57%) in the 4th week of life. The majority of HCMV-infected infants were asymptomatic, although they manifested microcephaly and low birth weight significantly more frequently (p = 0.006 and p = 0.02, respectively). Type HIV prophylaxis did not influence HCMV transmission.

CONCLUSIONS

Although often asymptomatic, HCMV infection in infants born to HIV-infected mothers is frequent and may be associated with prematurity, low birth weight, and microcephaly. Diagnostic procedures in children of HIV-infected mothers should involve HCMV.

Dengue virus infection of SK Hep1 cells: inhibition of in vitro angiogenesis and altered cytomorphology by expressed viral envelope glycoprotein

Dengue virus (DENV) infection of human endothelial cells has been implicated in the pathobiology of dengue hemorrhagic fever and dengue shock syndrome. However, the mechanisms by which DENV infections alter the functional physiology of endothelial cells remain incompletely understood. In the present study, we examined the susceptibility of a human liver sinusoidal endothelial cell line SK Hep1 to all four serotypes of DENV and studied the effect of the virus on in vitro angiogenesis. All four serotypes of DENV could infect the SK Hep1 cells, but showed variable cytopathic effects, the most pronounced being that of DENV-2. Electron microscopy of the infected cells showed significant ultrastructural changes. In vitro angiogenesis assays on DENV-2 exposed SK Hep1 cells in the matrigel system showed inhibition compared with the controls. Importantly, transfection and transient expression of the DENV-2 envelope glycoprotein (E) in these cells showed drastic alterations in cell shapes and the E protein could be localized by fluorescence microscopy in terminal knob-like structures. Therefore, SK Hep1, a human hepatic sinusoid-derived endothelial cell line, may constitute a potential model to study DENV-endothelial cell interactions in vitro, especially towards understanding the possible virus-induced changes in hepatic endothelium and its role in disease pathogenesis.

Implementing neonatal screening for congenital cytomegalovirus: addressing the deafness of policy makers

Congenital cytomegalovirus (CMV) infection is an important public health problem with approximately 7 in 1,000 newborns infected and consequently at risk for hearing impairment. Newborn hearing screening will fail to detect this hearing impairment in approximately half of the cases because late onset hearing loss is frequent. Hearing impairment has profound impact on cognitive and social development of children and their families, determining most of the disease burden of congenital CMV infection. The potential value of newborn screening for congenital CMV is increasingly discussed. To date, many experts acknowledge the benefit of antiviral treatment in the prevention of hearing deterioration in newborns with neurological symptoms, and the benefit of early identification of late-onset hearing impairment by means of extensive audiological follow up of infected infants. These opinions imply that the potential of newborn screening for CMV would lie in the identification of the large proportion of asymptomatic congenitally infected newborns at risk for developing late-onset hearing loss. Experience with postnatal antiviral treatment of symptomatic newborns is encouraging, but has not been studied in asymptomatic congenitally infected newborns. A large-scale study on the safety and effectiveness of combined screening and antiviral therapy for congenital CMV infection is the necessary next step to take and should not be delayed.