Universal newborn screening for congenital cytomegalovirus infection: feasibility and relevance in a French type-III maternity cohort.

OBJECTIVE: Evaluation of relevance and feasibility of universal newborn congenital cytomegalovirus infection (cCMVI) screening in saliva. DESIGN: Retrospective, population-based cohort study. SETTING: Clamart, France, 2016-2020. POPULATION: All neonates born consecutively in our level III maternity unit. METHODS: CMV PCR in saliva for all neonates at birth, and, if positive, CMV PCR in urine to confirm or exclude cCMVI. Prospective and retrospective characterisation of maternal infections. ROC curve analysis to assess saliva PCR performances. Acceptability of screening among staff members evaluated by a survey. MAIN OUTCOME MEASURES: Number of cCMVI neonates; number of expected and unexpected cCMVI. RESULTS: Among 15 341 tested neonates, 63 had cCMVI (birth prevalence of 0.4%, 95% CI 0.3-0.5). In 50% of cases, maternal infection was a non-primary infection (NPI) during pregnancy. cCMVI was expected or suspected (maternal primary infection [PI], antenatal or neonatal signs) in 24/63 neonates (38%), and unexpected in 39/63 neonates (62%). The best CMV saliva threshold to predict cCMVI was 356 (2.55 log) copies/ml [95% CI 2.52 log-3.18 log], with an area under the ROC curve of 0.97. Over 90% of the 72 surveyed staff members reported that the screening was easy and quick. No parent refused the screening. CONCLUSIONS: Universal screening for cCMVI with CMV PCR on saliva samples is feasible and highly acceptable to parents and healthcare providers. Over half (62%) of the cases had no prenatal/neonatal signs of cCMVI or a maternal history of CMV infection during pregnancy and would probably not have been diagnosed without universal screening. TWEETABLE ABSTRACT: In 62% of congenital cytomegalovirus infection cases, only universal neonatal screening in saliva can detect infection.

Human Cytomegalovirus Infection in Women With Preexisting Immunity: Sources of Infection and Mechanisms of Infection in the Presence of Antiviral Immunity.

Human cytomegalovirus (HCMV) infection remains an important cause of neurodevelopmental sequelae in infants infected in utero. Unique to the natural history of perinatal HCMV infections is the occurrence of congenital HCMV infections (cCMV) in women with existing immunity to HCMV, infections that have been designated as nonprimary maternal infection. In maternal populations with a high HCMV seroprevalence, cCMV that follows nonprimary maternal infections accounts for 75%-90% of all cases of cCMV infections as well as a large proportion of infected infants with neurodevelopmental sequelae. Although considerable effort has been directed toward understanding immune correlates that can modify maternal infections and intrauterine transmission, the source of virus leading to nonprimary maternal infections and intrauterine transmission is not well defined. Previous paradigms that included reactivation of latent virus as the source of infection in immune women have been challenged by studies demonstrating acquisition and transmission of antigenically distinct viruses, a finding suggesting that reinfection through exposure to an exogenous virus is responsible for some cases of nonprimary maternal infection. Additional understanding of the source(s) of virus that leads to nonprimary maternal infection will be of considerable value in the development and testing of interventions such as vaccines designed to limit the incidence of cCMV in populations with high HCMV seroprevalence.

Clinical factor associated with congenital cytomegalovirus infection in pregnant women with non-primary infection.

The aim of this nested case-control study was to evaluate clinical factors associated with the occurrence of congenital cytomegalovirus (CMV) infection in pregnant women with non-primary CMV infection. In a cohort study of CMV screening for 2193 pregnant women and their newborns, seven newborns with congenital CMV infection were identified among 1287 pregnant women with non-primary CMV infection that was defined as negative IgM and positive IgG with IgG avidity index >45%. In the 1287 women with non-primary CMV infection, clinical findings and complications were compared between pregnancies with and without congenital CMV infection. Clinical factors associated with the occurrence of congenital CMV infection were evaluated. The birth weight of newborns with congenital CMV infection was less than that of newborns without congenital infection (p < 0.05). Univariate logistic regression analyses demonstrated that threatened premature delivery (OR 10.6, 95%CI 2.0-55.0; p < 0.01) and multiple pregnancy (OR 7.1, 95%CI 1.4-37.4; p < 0.05) were associated with congenital infection. Multivariable logistic regression analyses demonstrated that threatened premature delivery (OR 8.4, 95%CI 1.5-48.1; p < 0.05) was a single risk factor for congenital CMV infection in pregnant women with non-primary CMV infection. This study revealed for the first time that threatened premature delivery was associated with the occurrence of congenital CMV infection in pregnant women with non-primary CMV infection, the pathophysiology of which may be closely associated with CMV reactivation during pregnancy.

Perinatal Outcomes of Non-Primary Maternal Cytomegalovirus Infection: A 15-Year Experience.

OBJECTIVE: To evaluate perinatal outcomes in case of non-primary maternal cytomegalovirus (CMV) infection. METHODS: We performed a retrospective cohort study of pregnant women with active CMV infection referred to our unit over a 15-year period (January 2000 to December 2014). Non-primary infection was diagnosed on the basis of the results of confirmatory serological and virological tests (avidity test, immunoblotting, real-time PCR-DNA). The vertical transmission rate and the percentage of symptomatic congenital infection were determined in this group of patients. RESULTS: A total of 205 pregnant women were enrolled. Congenital infection occurred in 7 (3.4%) fetuses/neonates. Symptomatic disease was present at birth in 3 of the 7 congenitally infected neonates (1.5%). Two out of 3 symptomatic newborns presented a pathologic second-trimester ultrasound scan. CONCLUSION: Maternal immunity offers substantial protection against intrauterine transmission of CMV infection, but not against disease once the fetus is infected.

Congenital Cytomegalovirus Infection in the Absence of Maternal Cytomegalovirus-IgM Antibodies.

BACKGROUND: Congenital cytomegalovirus (cCMV) infections are the most prevalent intrauterine infections worldwide and are the result of maternal primary or non-primary infections. Early maternal primary infections are thought to carry the highest risk of fetal developmental abnormalities as seen by ultrasound; however, non-primary infections may prove equally detrimental. METHODS/RESULTS: This case series presents 5 cases with fetal abnormalities detected in the second and third trimester, in which cCMV infection was ruled out due to negative maternal CMV-IgM. DISCUSSION: This series highlights the possible pitfalls in serology interpretation and fetal diagnosis necessary for appropriate parental counseling. Once fetal abnormalities have been confirmed and cCMV is suspected, maternal CMV serostatus and fetal infection should be determined. Maternal CMV serology may be ambiguous; therefore, caution should be exercised when interpreting the results.

Cytomegalovirus (CMV) seroprevalence among women at childbearing age, maternal and congenital CMV infection: policy implications of a descriptive, retrospective, community-based study.

BACKGROUND: Maternal CMV infection during pregnancy, either primary or non-primary, may be associated with fetal infection and long-term sequelae. While guidelines recommend against it, screening for CMV in pregnant women is a prevalent clinical practice in Israel. Our aim is to provide updated, local, clinically relevant, epidemiological information about CMV seroprevalence among women at childbearing age, the incidence of maternal CMV infection during pregnancy and the prevalence of congenital CMV (cCMV), as well as to provide information about the yield of CMV serology testing. METHODS: We performed a descriptive, retrospective study of women at childbearing age who were members of Clalit Health Services in the district of Jerusalem and had at least one gestation during the study period (2013-2019). We utilized serial serology tests to determine CMV serostatus at baseline and at pre/periconception and identified temporal changes in CMV serostatus. We then conducted a sub-sample analysis integrating inpatient data on newborns of women who gave birth in a single large medical center. cCMV was defined as either positive urine CMV-PCR test in a sample collected during the first 3 weeks of life, neonatal diagnosis of cCMV in the medical records, or prescription of valganciclovir during the neonatal period. RESULTS: The study population Included 45,634 women with 84,110 associated gestational events. Initial CMV serostatus was positive in 89% women, with variation across different ethno-socioeconomic subgroups. Based on consecutive serology tests, the detected incidence rate of CMV infection was 2/1000 women follow-up years, among initially seropositive women, and 80/1000 women follow-up years, among initially seronegative women. CMV infection in pregnancy was identified among 0.2% of women who were seropositive at pre/periconception and among 10% of women who were seronegative. In a subsample, which included 31,191 associated gestational events, we identified 54 newborns with cCMV (1.9/1000 live births). The prevalence of cCMV among newborns of women who were seropositive at pre/periconception was lower than among newborns of women who were seronegative (2.1 vs. 7.1/1000). Frequent serology tests among women who were seronegative at pre/periconception detected most primary CMV infections in pregnancy that resulted in cCMV (21/24). However, among women who were seropositive, serology tests prior to birth detected none of the non-primary infections that resulted in cCMV (0/30). CONCLUSIONS: In this retrospective community-based study among women of childbearing age characterized by multiparity and high seroprevalence of CMV, we find that consecutive CMV serology testing enabled to detect most primary CMV infections in pregnancy that led to cCMV in newborns but failed to detect non-primary CMV infections in pregnancy. Conducting CMV serology tests among seropositive women, despite guidelines' recommendations, has no clinical value, while it is costly and introduces further uncertainties and distress. We thus recommend against routine CMV serology testing among women who were seropositive in a prior serology test. We recommend CMV serology testing prior to pregnancy only among women known to be seronegative or women whose serology status is unknown.

Human cytomegalovirus non-primary infection during pregnancy: antibody response, risk factors and newborn outcome.

OBJECTIVES: Human cytomegalovirus (HCMV) non-primary infections can occur in pregnant women and may result in congenital infection. Comprehensive studies investigating the frequency, characteristics, risk factors and immune response of non-primary infection in pregnancy are missing, while the rate of vertical transmission is not known. METHODS: HCMV non-primary infection was investigated prospectively in 250 pregnant women. Blood and urine samples as well as saliva and vaginal swabs were collected at 13, 21 and 31 weeks of gestation and at delivery. HCMV-DNA and specific IgG and IgM levels were determined. RESULTS: Overall, 105/250 pregnant women (42.0%) developed non-primary infection. HCMV-DNA was detected more frequently in vaginal secretions (84/250 of the women, 33.6%) than in urine (35/250, 14.0%), saliva (26/250, 10.4%) and blood (7/250, 3.0%). The rate of HCMV non-primary infection increased significantly with the progression of pregnancy (from 12.9% in the first trimesters of gestation to 21.9% at delivery, p < 0.01). IgM was detected in 25/250 of the women (10.0%), with no association with non-primary infection, while anti-gB IgG was significantly higher (p < 0.01) in women with non-primary infection. Age and close contact with children were not associated with non-primary infection. No woman with non-primary infection transmitted the infection to the fetus (95% confidence interval of transmission rate: 0-3.5%). DISCUSSION: Although HCMV non-primary infection is frequent during pregnancy, the rate of congenital infection as a consequence of non-primary infection is likely to be ≤ 3.5%.

Cytomegalovirus Specific Serological and Molecular Markers in a Series of Pregnant Women With Cytomegalovirus Non Primary Infection.

(1) Background: In a period where systematic screening of CMV during pregnancy is still debated, diagnosis of non primary infection (NPI) remains challenging and an obstacle to systematic screening. Our aim is to report kinetics of serological and molecular CMV markers of NPI. (2) Methods: We identified immunocompetent pregnant women with CMV NPI as women known to be seropositive for CMV before pregnancy who gave birth to cCMV infected infants. We performed CMV-IgG, CMV-IgM, CMV-IgG avidity and CMV PCR retrospectively on sequential serum samples collected during pregnancy. (3) Results: We collected 195 serum samples from 53 pregnant women with NPI during pregnancy. For 29/53 (55%) patients, no markers of active infection were observed (stable IgG titers, negative IgM and negative PCR). CMV PCR was positive in at least one serum for 18/53 (34%) patients and median viral load was 46 copies/mL, IQR (21-65). (4) Conclusions: For more than half of patients with confirmed CMV NPI during pregnancy, available diagnostic tools are liable to fail in detecting an active infection. These should therefore not be used and universal neonatal screening for CMV remains the only way to detect all cCMV infections.

Detection of Genotype-Specific Antibody Responses to Glycoproteins B and H in Primary and Non-Primary Human Cytomegalovirus Infections by Peptide-Based ELISA.

BACKGROUND: Strain-specific antibodies to human cytomegalovirus (HCMV) glycoproteins B and H (gB and gH) have been proposed as a potential diagnostic tool for identifying reinfection. We investigated genotype-specific IgG antibody responses in parallel with defining the gB and gH genotypes of the infecting viral strains. METHODS: Subjects with primary (n = 20) or non-primary (n = 25) HCMV infection were studied. The seven gB (gB1-7) and two gH (gH1-2) genotypes were determined by real-time PCR and whole viral genome sequencing, and genotype-specific IgG antibodies were measured by a peptide-based enzyme-linked immunosorbent assay (ELISA). RESULTS: Among subjects with primary infection, 73% (n = 8) infected by gB1-HCMV and 63% (n = 5) infected by gB2/3-HCMV had genotype-specific IgG antibodies to gB (gB2 and gB3 are similar in the region tested). Peptides from the rarer gB4-gB7 genotypes had nonspecific antibody responses. All subjects infected by gH1-HCMV and 86% (n = 6) infected by gH2-HCMV developed genotype-specific responses. Among women with non-primary infection, gB and gH genotype-specific IgG antibodies were detected in 40% (n = 10) and 80% (n = 20) of subjects, respectively. CONCLUSIONS: Peptide-based ELISA is capable of detecting primary genotype-specific IgG responses to HCMV gB and gH, and could be adopted for identifying reinfections. However, about half of the subjects did not have genotype-specific IgG antibodies to gB.

Human Cytomegalovirus Congenital (cCMV) Infection Following Primary and Nonprimary Maternal Infection: Perspectives of Prevention through Vaccine Development.

Congenital cytomegalovirus (cCMV) might occur as a result of the human cytomegalovirus (HCMV) primary (PI) or nonprimary infection (NPI) in pregnant women. Immune correlates of protection against cCMV have been partly identified only for PI. Following either PI or NPI, HCMV strains undergo latency. From a diagnostic standpoint, while the serological criteria for the diagnosis of PI are well-established, those for the diagnosis of NPI are still incomplete. Thus far, a recombinant gB subunit vaccine has provided the best results in terms of partial protection. This partial efficacy was hypothetically attributed to the post-fusion instead of the pre-fusion conformation of the gB present in the vaccine. Future efforts should be addressed to verify whether a new recombinant gB pre-fusion vaccine would provide better results in terms of prevention of both PI and NPI. It is still a matter of debate whether human hyperimmune globulin are able to protect from HCMV vertical transmission. In conclusion, the development of an HCMV vaccine that would prevent a significant portion of PI would be a major step forward in the development of a vaccine for both PI and NPI.

False human cytomegalovirus IgG-positivity at prenatal screening.

BACKGROUND: An incorrect definition of immune status to human cytomegalovirus (HCMV) can lead to incorrect management of pregnant women. OBJECTIVES: Aims of the study were: i) to describe 10 cases of unconfirmed HCMV IgG-seroconversion in pregnancy; ii) to develop a panel of confirmatory tests to define HCMV serostatus; iii) to investigate the frequency of false IgG-positive results in pregnant women screened with the LIAISON®CMVIgGII automated assay. STUDY DESIGN: Blood samples from 10 pregnant women referred for HCMV IgG-seroconversion were examined to confirm/exclude a primary infection. In addition, samples were tested for HCMV IgG by immunoblotting, neutralization assay, and ELISA against gB, gH/gL/pUL128L and gH/gL/gO recombinant glycoproteins. LIAISON®CMVIgGII results obtained on 1158 pregnant women were reviewed and samples with low IgG titers were further investigated. RESULTS: A primary infection was excluded in the 10 women referred for HCMV IgG seroconversion. None of them was confirmed to be IgG-seropositive. Of the 1158 women prenatally screened by LIAISON®CMVIgGII, 678 (59%) were IgG-positive and, of these, 40 (5.9%) showed low levels of IgG (14-50 U/mL). Thirty-three women with low IgG-positivity were further tested by confirmatory tests and 11 (33.3%) were found to be non reactive to HCMV. CONCLUSIONS: At least 1.6% (11/678) women who tested positive with LIAISON®CMVIgGII were found to be seronegative when tested with confirmatory tests. These women should be informed to reduce the risk of a primary HCMV infection. Furthermore, should a congenital infection occur in any of these women, a maternal non-primary infection could be erroneously diagnosed.

Cytomegalovirus non-primary infection during pregnancy. Can serology help with diagnosis?

Diagnosis of cytomegalovirus (CMV) primary infection is reliable, but diagnosis of CMV non-primary infection (NPI) is questionable. Our aim is to highlight the difficulties met in diagnosis of CMV NPI. We illustrate that in proven cases of CMV NPI, very different serologic and molecular patterns may be observed and that routine serologic testing may fail to help with diagnosis. These results point out that many data available in literature concerning the prevalence of NPI, materno-fetal transmission rates and consequences of NPI may be wrong. We need to know how frequently they occur, are transmitted and cause fetal damages. Diagnosis of NPI must be improved, along with our understanding of the mechanisms leading to intrauterine CMV transmission and congenital infection in babies born to women with preexisting immunity.

Primary versus non-primary maternal cytomegalovirus infection as a cause of symptomatic congenital infection - register-based study from Finland.

BACKGROUND: Both primary and non-primary maternal cytomegalovirus (CMV) infection during pregnancy can lead to vertical transmission. We evaluated the proportion of maternal primary/non-primary infections among 26 babies with symptomatic congenital CMV infection born in Finland from 2000 to 2012. METHODS: We executed a database search on hospital records from all five university hospitals in Finland to identify infants with congenital CMV infection. The preserved maternal serum samples drawn at the end of the first trimester were analysed for CMV antibodies. Maternal infection was classified to be non-primary, if there was high avidity CMV immunoglobulin G (IgG) in the early pregnancy samples. Infection was considered primary in the case of either low avidity IgG (primary infection in the first trimester or near conception) or absent CMV IgG at the end of the first trimester (primary infection in the second or third trimester). RESULTS: The majority of the symptomatic congenital CMV infections (54%) were due to maternal non-primary infection, 27% due to maternal primary infection in the first trimester or near conception, and 19% during the second or third trimester. Long-term sequelae occurred in 59% of patients: in 6/7 after primary infection in the first trimester, in 0/5 after primary infection in the second or third trimester, and in 9/14 after non-primary infection. CONCLUSIONS: In this register-based cohort, non-primary infections caused the majority of symptomatic congenital CMV infections, and resulted in significant morbidity.

Cytomegalovirus DNAemia in pregnant women.

BACKGROUND: Cytomegalovirus (CMV) transmission from mother to fetus occurs at a much greater rate following primary rather than reactivated infections and CMV dissemination in the mother is considered a key step in the pathogenesis of fetal infection. However, knowledge of CMV DNAemia in CMV-seropositive pregnant women is very limited. OBJECTIVE: Major objective of this study was to assess the prevalence and diagnostic value of CMV DNAemia in a large population of seropositive pregnant women. STUDY DESIGN: Serologic and DNAemia results obtained from 2211 blood samples of 1371 consecutive pregnant women referred to our Institution for suspected CMV infection in the period 2001-2010 were reviewed. RESULTS: DNAemia was detected in 452/597 (75.7%) women with serologic evidence of primary CMV infection and in 4/774 (0.5%) women without evidence of primary infection. CONCLUSION: In pregnant women, CMV DNAemia is detected primarily during primary infection. CMV DNAemia determination may be helpful in the diagnosis of primary infection.